N8974A Service Guide

N8974A Service Guide
Service Guide
Agilent Technologies
NFA Series Noise Figure Analyzers
This manual provides documentation for the following instruments:
Agilent Technologies NFA Series
N8972A (10 MHz - 1.5 GHz)
N8973A (10 MHz - 3.0 GHz)
N8974A (10 MHz - 6.7 GHz)
N8975A (10 MHz - 26.5 GHz)
Manufacturing Part Number: N8972-90004
Printed in UK
December 2001
© Copyright 2000, 2001 Agilent Technologies, Inc.
The information contained in this document is subject to change without notice.
Agilent Technologies makes no warranty of any kind with regard to this material,
including but not limited to, the implied warranties of merchantability and fitness
for a particular purpose. Agilent Technologies shall not be liable for errors
contained herein or for incidental or consequential damages in connection with the
furnishing, performance, or use of this material.
Safety Notes
This instrument has been designed and tested in accordance with publication
EN61010-1(1993) / IEC 61010-1(1990) +A1(1992) +A2(1995) / CSA C22.2 No.
1010.1(1993) Safety Requirements for Electrical Equipment for Measurement,
Control and Laboratory Use, and has been supplied in a safe condition. The
instruction documentation contains information and warnings which must be
followed by the user to ensure safe operation and to maintain the instrument in a
safe condition.
The following examples illustrate warning and caution statements that are used
throughout this manual.
WARNING
These servicing instructions are for use by qualified personnel only. To avoid
electrical shock, do not perform any servicing unless you are qualified to do
so.
WARNING
Warning denotes a hazard. It calls attention to a procedure which, if not
correctly performed or adhered to, could result in injury or loss of life. Do not
proceed beyond a warning note until the indicated conditions are fully
understood and met.
CAUTION
Caution denotes a hazard. It calls attention to a procedure that, if not correctly
performed or adhered to, could result in damage to or destruction of the
instrument. Do not proceed beyond a caution sign until the indicated conditions are
fully understood and met.
The following safety notes are used throughout this manual. Familiarize yourself
with each of the notes and its meaning before operating this instrument.
WARNING
This is a Safety Class 1 Product (provided with a protective earthing ground
incorporated in the power cord). The mains plug shall only be inserted in a
socket outlet provided with a protected earth contact. Any interruption of the
protective conductor inside or outside of the product is likely to make the
product dangerous. Intentional interruption is prohibited.
ii
WARNING
The opening of covers or removal of parts is likely to expose dangerous
voltages. Disconnect the product from all voltage sources while it is being
opened.
WARNING
The noise figure analyzer contains potentially hazardous voltages. Refer to
the safety symbols on the noise figure analyzer and the general safety notes in
this service guide before operating the unit with the cover removed. Failure to
heed the safety precautions can result in severe or fatal injury.
WARNING
If this product is not used as specified, the protection provided by the
equipment could be impaired. This product must be used in a normal
condition (in which all means for protection are intact) only.
WARNING
The power cord is connected to internal capacitors that may remain live for
five seconds after disconnecting the plug from the power supply.
CAUTION
This instrument is designed for use in Installation Category II and Pollution
Degree 2 per IEC61010 and 60664 respectively.
Warranty
This Agilent Technologies instrument product is warranted against defects in
material and workmanship for a period of three year from date of shipment. During
the warranty period, Agilent Technologies will, at its option, either repair or
replace products which prove to be defective.
For warranty service or repair, this product must be returned to a service facility
designated by Agilent Technologies. Buyer shall prepay shipping charges to
Agilent Technologies and Agilent Technologies shall pay shipping charges to
return the product to Buyer. However, Buyer shall pay all shipping charges, duties,
and taxes for products returned to Agilent Technologies from another country.
Agilent Technologies warrants that its software and firmware designated by
Agilent Technologies for use with an instrument will execute its programming
instructions when properly installed on that instrument. Agilent Technologies does
not warrant that the operation of the instrument, or software, or firmware will be
uninterrupted or error-free.
iii
LIMITATION OF WARRANTY
The foregoing warranty shall not apply to defects resulting from improper or
inadequate maintenance by Buyer, Buyer-supplied software or interfacing,
unauthorized modification or misuse, operation outside of the environmental
specifications for the product, or improper site preparation or maintenance.
NO OTHER WARRANTY IS EXPRESSED OR IMPLIED. AGILENT
TECHNOLOGIES SPECIFICALLY DISCLAIMS THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE.
EXCLUSIVE REMEDIES
THE REMEDIES PROVIDED HEREIN ARE BUYER’S SOLE AND
EXCLUSIVE REMEDIES. AGILENT TECHNOLOGIES SHALL NOT BE
LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR
CONSEQUENTIAL DAMAGES, WHETHER BASED ON CONTRACT, TORT,
OR ANY OTHER LEGAL THEORY.
Lithium Battery Disposal
When the battery on the A4 processor assembly (3 volt lithium battery, part
number 1420-0338) is exhausted and/or ready for disposal, dispose of it according
to your country’s requirements. You can return the battery to your nearest Agilent
Technologies Sales and Service office for disposal, if required. Refer to
“Contacting Agilent Technologies, Inc.” in Chapter 5 in for a list of Agilent
Technologies Sales and Service offices.
DO NOT THROW BATTERIES AWAY BUT
COLLECT AS SMALL CHEMICAL WASTE.
sk780a
iv
Contents
1. Troubleshooting the Noise Figure Analyzer (NFA)
What You Will Find in This Chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Before You Start. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Replacement Assemblies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
After an NFA Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
ESD Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Protection from Electrostatic Discharge . . . . . . . . . . . . . . . . . . . . . . .5
Handling of Electronic Components and ESD. . . . . . . . . . . . . . . . . . .7
Test Equipment Usage and ESD . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
For Additional Information about ESD . . . . . . . . . . . . . . . . . . . . . . . .7
Service Equipment You Will Need . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Check the Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Firmware Upgrades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Firmware Installation Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Problems at Instrument Power-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Potentially Serious Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Clicking Noises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
The NFA Always Powered On . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Troubleshooting an Inoperative NFA . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Check the NFA Setup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Initial Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
If the Line Fuse Has Blown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
If the Fan is Not Running . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Checking the Power Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
If All Low Voltage Supplies Are Faulty . . . . . . . . . . . . . . . . . . . . . . .16
If Some Low Voltage Supplies Are Faulty . . . . . . . . . . . . . . . . . . . . .16
Checking the Power Supplies Without a Test Board . . . . . . . . . . . . . .17
Troubleshooting the LCD Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Using the Internal Service-Diagnostic Routines . . . . . . . . . . . . . . . . . . .20
v
Contents
Timebase (in Service Menu) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Noise Source On or Off (in Service Menu) . . . . . . . . . . . . . . . . . . . . . .
Align YTF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IF Test (in Service Menu) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Write to SNS (in Service Menu) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Restore System Defaults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Panel Test (in Diagnostic Menu) . . . . . . . . . . . . . . . . . . . . . . . .
20
20
21
21
21
21
22
Troubleshooting the A4 Processor Assembly . . . . . . . . . . . . . . . . . . . . .
Initial Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bootrom Self-Test Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clearing Dynamic RAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23
23
24
25
Troubleshooting the A6 Floppy Drive Assembly . . . . . . . . . . . . . . . . . . 26
Troubleshooting the A7A1 GPIB Assembly . . . . . . . . . . . . . . . . . . . . . .
Printer Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GPIB Faults and Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Communicating with the NFA using N2716A Software . . . . . . . . .
27
27
28
28
Troubleshooting the A7A2 SIB Assembly . . . . . . . . . . . . . . . . . . . . . . . .
RS 232 Faults and Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LO GPIB Faults and Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting the +28V Noise Source supply . . . . . . . . . . . . . . . . .
Smart Noise Source (SNS) Faults and Errors . . . . . . . . . . . . . . . . . .
29
29
29
29
31
Troubleshooting the A7A4 DSP Assembly . . . . . . . . . . . . . . . . . . . . . . . 32
Troubleshooting the A7A5 IF Assembly . . . . . . . . . . . . . . . . . . . . . . . . .
The Clock Signal Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IF Gain Control Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bandwidth Shape Check. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Noisy Assembly Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
When replacing the IF Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Setting up and Using the VEE Program . . . . . . . . . . . . . . . . . . . . . . .
vi
34
34
35
35
36
37
37
Contents
Installing the VEE Runtme Environment . . . . . . . . . . . . . . . . . . . . .37
Running the VEE program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
2. Troubleshooting the Front End and RF Sections
What You Will Find in This Chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
Recommended Test Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
Recommended Connector Torque Settings . . . . . . . . . . . . . . . . . . . . . .40
Checking the Measurement Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
Troubleshooting the A2 Front End and Input Stage . . . . . . . . . . . . . . . .42
RF Front End and Input Stage Verification Procedure . . . . . . . . . . . .42
Test Point A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
Test Point B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
Test Point C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
Test Point D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
Troubleshooting the A3 Microwave Front End, A2 Front End, and Input
Stage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
RF Front End and Input Stage “Quick Check” Verification Procedure in
Low Band . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
Test Point A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
Test Point B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
Test Point C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
Test Point D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49
Quick Check RF Procedure for High Bands . . . . . . . . . . . . . . . . . . . . .50
Test Point E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50
Test Point F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
Verifying the A8 RF Section Performance . . . . . . . . . . . . . . . . . . . . . . . .52
Quick A8 Troubleshooting Procedure . . . . . . . . . . . . . . . . . . . . . . . . . .52
Another Quick Check using the 10.0 MHz Out Frequency Reference
Accuracy Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
Detailed A8 RF Troubleshooting Procedure . . . . . . . . . . . . . . . . . . . . .54
vii
Contents
Verifying the A8 RF Section Performance . . . . . . . . . . . . . . . . . . . . . . .
Quick Troubleshooting Procedure in Low Band . . . . . . . . . . . . . . . . .
Additional Quick Troubleshooting Information . . . . . . . . . . . . . . . .
Detailed Troubleshooting Procedure in Low Band . . . . . . . . . . . . . . .
Quick Troubleshooting Procedure in High Bands. . . . . . . . . . . . . . . .
Additional Quick Troubleshooting Information . . . . . . . . . . . . . . . .
Detailed RF Troubleshooting for High Bands . . . . . . . . . . . . . . . . . . .
59
59
60
61
68
69
70
Verifying the RF Input Attenuator and the Second Converter Switch
Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Verifying the RF Input Attenuator Driver Functionality . . . . . . . . . . 77
Verifying the second Converter Switch Logic . . . . . . . . . . . . . . . . . . . 78
3. Error Messages
What You Will Find in This Chapter. . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Error Messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Informational Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Error Queues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Error Message Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Error Message Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
0: No Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
-499 to -400: Query Errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
-199 to -100: Command Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
-399 to -300 and 201 to 799: Device-Specific Errors. . . . . . . . . . . . . . 94
-299 to -200: Execution Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
4. Assembly Descriptions and Block Diagrams
What You Will Find in This Chapter. . . . . . . . . . . . . . . . . . . . . . . . . . . 112
A8 RF Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
Input Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
A8A1 RF Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
viii
Contents
A8A1A1 Reference/Third Converter . . . . . . . . . . . . . . . . . . . . . . . . . .115
A8A1A2 Front End/LO. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115
A8A2 Second Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116
A8A4 LO Amplifier/IF Switch (LOIS) . . . . . . . . . . . . . . . . . . . . . . . . .116
A8A5 Input Attenuator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116
A8A6 YIG-Tuned Filter/Mixer (RYTHM) . . . . . . . . . . . . . . . . . . . . . .116
A8FL1 3.1 GHz Low-Pass Filter (LPF) . . . . . . . . . . . . . . . . . . . . . . . .116
A2 RF Front End . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .117
A3 Microwave Front End . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .117
A7A3 Frequency Extension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .117
A7A5 IF Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .118
IF Gain Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .118
4.0 MHz Bandwidth Measurements . . . . . . . . . . . . . . . . . . . . . . . . . .118
Narrow Bandwidth Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . .118
IF Detector Linearity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .118
A4 Processor Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .119
NFA Battery Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .119
Interconnections to Other Assemblies . . . . . . . . . . . . . . . . . . . . . . . .120
A4A1 Flash SIMM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120
A4A2 DRAM SIMM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120
A5 Power Supply Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121
Interconnections to Other Assemblies . . . . . . . . . . . . . . . . . . . . . . . .121
A7 Motherboard and Card Cage Assemblies . . . . . . . . . . . . . . . . . . . . .122
A7A1 GPIB Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .122
A7A2 SIB Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .122
A7A4 DSP Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .122
Miscellaneous. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .123
A1 Display/Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .123
Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .123
A1A1 Front Panel Interface Board. . . . . . . . . . . . . . . . . . . . . . . . . .123
ix
Contents
A1A4 Backlight Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
A6 Floppy Drive Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Block Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
5. Parts List
What You Will Find in This Chapter. . . . . . . . . . . . . . . . . . . . . . . . . . . 132
How to Order Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Direct Mail-Order System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Direct Phone-Order System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Regular and Hotline Orders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
133
133
134
134
Replaceable Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
Contacting Agilent Technologies, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Instrument Serial Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
How to Return Your Analyzer for Service . . . . . . . . . . . . . . . . . . . . . .
Service Tag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Original Packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other Packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
142
142
142
144
6. Replacing Assemblies
What You Will Find in This Chapter. . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Before You Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
Service tools you will need . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
After a noise figure analyzer repair . . . . . . . . . . . . . . . . . . . . . . . . . 147
Removal and Replacement Procedures in This Chapter . . . . . . . . . . . 148
Instrument Outer Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Chassis Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
x
Contents
A1 Front Frame Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .155
Extension of the Front Frame Assembly. . . . . . . . . . . . . . . . . . . . . . .155
Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .156
Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .158
A1MP16 Nameplate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .159
Removal and Replacement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .159
Connector Label . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .160
Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .160
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .162
Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .163
Front Frame Subassemblies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .164
A1A2 Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .164
A1A1 Front Panel Interface Board . . . . . . . . . . . . . . . . . . . . . . . . . . .167
Front Panel RPG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .169
Removal/Replacement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .169
Keypad/Flex Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .170
A1A3MP9 Lens/Keypad Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . .171
A1A2DS1/A1A2DS2 Display Backlight. . . . . . . . . . . . . . . . . . . . . . . .172
A1MP11 Media Door/Bezel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .173
MP7 Vibration Support Bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .174
A3 Microwave Front End Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . .177
A2 RF Front End . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .179
A4 Processor Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .181
A4A1 and A4A2 Flash and DRAM SIMM . . . . . . . . . . . . . . . . . . . . . . .183
A4BT1 Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .184
A5 Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .185
A5B1 Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .187
xi
Contents
A6 Floppy Disc Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
A7 Motherboard Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
Card Cage Assemblies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
GPIB, RS-232, Frequency Extension, DSP, IF . . . . . . . . . . . . . . . . . 194
A8 RF Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
A8 Sub-assemblies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A8A4 LO Amp/IF Switch Assembly . . . . . . . . . . . . . . . . . . . . . . . . . .
A8A6 YIG-Tuned Filter/Mixer . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A8A5 Input Attenuator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A8A2 Second Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
203
203
204
207
209
213
7. Post-Repair Procedures
What You Will Find in This Chapter. . . . . . . . . . . . . . . . . . . . . . . . . . . 216
Before You Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
Post-Repair Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
Performance Verification and Adjustment Procedures . . . . . . . . . . . . 219
Performance Verification Procedures. . . . . . . . . . . . . . . . . . . . . . . . . 219
Adjustment Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
Agilent N2716A Performance Verification Software . . . . . . . . . . . . . . 220
Test Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
Performance Verification Tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
xii
1
Troubleshooting the Noise Figure
Analyzer (NFA)
Chapter 1
1
Troubleshooting the Noise Figure Analyzer (NFA)
What You Will Find in This Chapter
What You Will Find in This Chapter
This chapter provides information that is useful when starting to troubleshoot an
NFA failure. It provides procedures for troubleshooting common failures and
isolating problems in the NFA. Assembly descriptions are located in Chapter 4,
“Assembly Descriptions and Block Diagrams.”
Chapter 2, “Troubleshooting the Front End and RF Sections,” describes how to
troubleshoot a failure in the measurement path, where the noise energy is down
converted to the Intermediate Frequency (IF).
2
Chapter 1
Troubleshooting the Noise Figure Analyzer (NFA)
Before You Start
Before You Start
There are four things you should do before starting to troubleshoot a failure:
•
Check that you are familiar with the safety symbols marked on the instrument
and read the general safety considerations and the safety note definitions given
in the front of this guide.
•
The NFA contains static sensitive components. Read the section entitled “ESD
Information” on page 5 in this chapter.
•
Become familiar with the organization of the troubleshooting information in
this chapter.
•
Read the rest of this section.
WARNING
These servicing instructions are for use by qualified personnel only. To avoid
electrical shock, do not perform any servicing unless you are qualified to do
so.
WARNING
The opening of covers or removal of parts is likely to expose dangerous
voltages. Disconnect the product from all voltage sources while it is being
opened.
WARNING
The detachable power cord is the instrument disconnecting device. It
disconnects the mains circuits from the mains supply before other parts of the
instrument. The front panel switch is only a standby switch and is not a LINE
switch (disconnecting device).
CAUTION
Always position the instrument for easy access to the disconnecting device
(detachable power cord).
WARNING
To prevent electrical shock, disconnect the Noise Figure Analyzer from mains
before cleaning. Use a dry cloth or one slightly dampened with water to clean
the external case parts. Do not attempt to clean internally.
WARNING
For continued protection against fire hazard, replace the line fuse only with
same type and ratings (type 5A/250V). The use of other fuses or materials is
prohibited.
Chapter 1
3
Troubleshooting the Noise Figure Analyzer (NFA)
Before You Start
WARNING
This is a Safety Class 1 Product (provided with a protective earthing ground
incorporated in the power cord). The mains plug shall only be inserted in a
socket outlet provided with a protective earth contact. Any interruption of the
protective conductor inside or outside of the product is likely to make the
product dangerous. Intentional interruption is prohibited.
CAUTION
Always use the three-prong ac power cord supplied with this product. Failure to
ensure adequate earth grounding by not using this cord may cause product damage.
CAUTION
Before switching on this instrument, make sure that:
•
•
The correct fuse is installed.
The supply voltage is in the specified range.
As the instrument has an autoranging line voltage input, the supply voltage
range is 90 Vac to 130 Vac or 200 Vac to 260Vac.
Replacement Assemblies
The NFA assemblies are not repairable to component level. Therefore the
following assemblies must be replaced as a full assembly.
•
Display interface board (A1A1).
•
Display (A1A2).
•
Front end (A2).
•
Microwave front end assembly (A3) used on N8974A and N8975A.
•
Processor assembly (A4).
•
Power supply assembly (A5).
•
Floppy drive assembly (A6).
•
Motherboard (A7).
•
GPIB board (A7A1).
•
RS-232 board (A7A2).
•
Frequency extension assembly (A7A3) used on N8974A and N8975A.
•
DSP assembly (A7A4) not used on N8972A.
•
IF assembly (A7A5).
•
RF assembly (A8).
•
RF and microwave front end input microcircuits (A8Ax).
4
Chapter 1
Troubleshooting the Noise Figure Analyzer (NFA)
Before You Start
After an NFA Repair
If one or more NFA assemblies have been repaired or replaced, perform the
performance verification tests and any adjustments needed. Refer to Chapter 7,
“Post-Repair Procedures,” for further information on the adjustments and
performance verification tests.
The adjustments and performance verification tests can be done using the Agilent
N2716A Performance Verification and Adjustment Software. The software can be
purchased through your local Agilent Technologies sales and service office. (See
“Contacting Agilent Technologies, Inc.” on page 140.)
NOTE
Option 0BW does not include performance verification software. Performance
verification can be done manually using the procedures in the calibration guide.
ESD Information
Protection from Electrostatic Discharge
Electrostatic discharge (ESD) can damage or destroy electronic components. All
work on electronic assemblies should be performed at a static-safe workstation.
Figure 1-1 shows an example of a static-safe workstation using two types of ESD
protection:
•
Conductive table-mat and wrist-strap combination.
•
Conductive floor-mat and heel-strap combination.
Both types, when used together, provide a significant level of ESD protection. Of
the two, only the table-mat and wrist-strap combination provides adequate ESD
protection when used alone. To ensure user safety, the static-safe accessories must
provide at least 1 megohm of isolation from ground. Refer to Table 1-1 for
information on ordering static-safe accessories.
WARNING
These techniques for a static-safe workstation should not be used when
working on circuitry with a voltage potential greater than 500 volts.
Chapter 1
5
Troubleshooting the Noise Figure Analyzer (NFA)
Before You Start
Figure 1-1
Example of a Static-Safe Workstation
Table 1-1
Static Safe Accessories
Part Number
Description
85043-80013
Set includes: 3M static control mat 0.4 m × 0.6 m (16 inches × 23
inches) and 4.6 cm (15 ft) ground wire, wrist strap, and wrist-strap cord.
9300-0980
Wrist-strap cord 1.5 m (5 ft).
9300-1367
Wrist-strap, color black, stainless steel, without cord, has four adjustable
links and a 7 mm post-type connection.
9300-1308
ESD heel-strap (reusable 6 to 12 months).
6
Chapter 1
Troubleshooting the Noise Figure Analyzer (NFA)
Before You Start
Handling of Electronic Components and ESD
The possibility of unseen damage caused by ESD is present whenever components
are transported, stored, or used. The risk of ESD damage can be greatly reduced by
close attention to how all components are handled.
CAUTION
•
Perform work on all components at a static-safe workstation.
•
Keep static-generating materials at least one meter away from all components.
•
Store or transport components in static-shielding containers.
Always handle printed circuit board assemblies by the edges. This will reduce the
possibility of ESD damage to components and prevent contamination of exposed
plating.
Test Equipment Usage and ESD
•
Before connecting any coaxial cable to an NFA connector, momentarily short
the center and outer conductors of the cable together.
•
Personnel should be grounded with a 1 megohm resistor-isolated wrist-strap
before touching the center pin of any connector and before removing any
assembly from the NFA.
•
Be sure that all NFAs are properly earth-grounded to prevent build-up of static
charge.
For Additional Information about ESD
For more information about preventing ESD damage, contact the Electrical Over
Stress/Electrostatic Discharge (EOS/ESD) Association, Inc. The ESD standards
developed by this agency are sanctioned by the American National Standards
Institute (ANSI).
Chapter 1
7
Troubleshooting the Noise Figure Analyzer (NFA)
Service Equipment You Will Need
Service Equipment You Will Need
In addition to the troubleshooting aids listed in Table 1-2, refer to Table 2-1 and the
N2716A Getting Started Guide or the NFA Noise Figure Analyzers Calibration And
Performance Verification Guide for a list of the recommended equipment needed
to troubleshoot and repair the NFA. Although Agilent Technologies equipment is
recommended, any manually operated equipment that meets the critical
specifications can be substituted for the recommended model.
Table 1-2
Troubleshooting Aids
8
Part number
Description
E4401-60235
Power supply service test board.
E4401-60240
Attenuator and second converter board assembly and
cable consisting of the following:
•
E4401-60236
•
Second converter driver test board
•
E4401-60239
•
24-Pin ribbon cable assembly.
E4401-60237
40-Pin extender board.
E4401-60238
100-Pin extender board.
Chapter 1
Troubleshooting the Noise Figure Analyzer (NFA)
Check the Basics
Check the Basics
A problem can often be resolved by repeating the procedure you were following
when the problem occurred. Before calling Agilent Technologies or returning the
NFA for service, please make the following checks:
•
Check the line fuse. See the section “If the Line Fuse Has Blown” on page 13.
•
Is there power at the receptacle?
•
Is the NFA turned on? Make sure the fan is running, which indicates that the
power supply is on. See the section “If the Fan is Not Running” on page 13.
•
If the display is dark or dim, press the upper Viewing Angle key in the
upper-left corner of the front panel. If the display is too bright, adjust the lower
Viewing Angle key in the upper-left corner of the front panel. See the section
“Troubleshooting the LCD Display” on page 18.
•
If other equipment, cables, and connectors are being used with your NFA, make
sure they are connected correctly and operating correctly.
•
Review the procedure for the measurement being performed when the problem
appeared. Are all the settings correct?
•
If the NFA is not functioning as expected, return the NFA to a known state by
pressing the Preset key.
Some NFA settings are not affected by a Preset. Refer to the “Front Panel
Key Reference” chapter of the User’s Guide for information on settings
affected by a Preset.
•
Is a measurement being performed? And are the expected results within the
specifications and capabilities of the NFA? Refer to the appropriate “Technical
Specifications” chapter in the Agilent NFA Series Calibration and Performance
and Verification Guide for more details.
•
In order to meet specifications, the NFA must be aligned. To verify that
Alignment is selected, press the System key, Alignment menu key and
enable Alignment (On). Refer to the “Front Panel Key Reference” chapter in
the User’s Guide for more details.
•
Is the NFA displaying an error message? If so, refer to
Chapter 3, “Error Messages.”
•
If the necessary test equipment is available, perform the performance
verification tests in the Agilent NFA Series Calibration and Performance and
Verification Guide. Record all results on the appropriate model’s Test Record
form. The form is contained in the Agilent NFA Series Calibration and
Performance and Verification Guide.
Chapter 1
9
Troubleshooting the Noise Figure Analyzer (NFA)
Check the Basics
Firmware Upgrades
It may be necessary to upgrade the firmware. The standard procedure for
upgrading the NFA’s firmware is using the A6 Floppy disk drive. The disks can be
ordered directly from Agilent or the data downloaded from the Agilent web site at
http://www.agilent.com/cm/wireless/nfa.html.
If you use the web site to obtain the latest Firmware Revisions click on NFA
Series Firmware Upgrade.
The firmware is supported using 6 disks. Disk 1 contains the loader information.
Disks 2 to 6 contain the firmware.
Firmware Installation Procedure
Step 1. Ensure the NFA is powered off.
Step 2. Insert the Loader disk into the NFA’s floppy drive.
Step 3. Power on the NFA. (This may take several seconds to boot)
NOTE
The Loader revision shown on the NFA screen may have a different version
number from the firmware being loaded.
CAUTION
Do not to recycle the power until prompted. This prompt occurs when the
installation is complete.
Step 4. Follow the on-screen instructions, inserting each disk when prompted.
Step 5. When re-booting the splash screen displays the new revision of firmware.
10
Chapter 1
Troubleshooting the Noise Figure Analyzer (NFA)
Problems at Instrument Power-Up
Problems at Instrument Power-Up
This section describes symptoms that can occur when the NFA is first powered on.
Potentially Serious Faults
CAUTION
Immediately unplug the NFA from the ac power line if the unit shows any of the
following symptoms:
•
Smoke, arcing, or unusual noise from inside the unit, except the “Clicking
Noises” discussed below.
•
No response of any kind when unit is plugged into ac power mains and turned
on.
•
The NFA ac power fuse blows.
•
A circuit breaker or fuse on the main ac power line opens.
These potentially serious faults must be corrected before proceeding. Refer to
“Troubleshooting an Inoperative NFA” on page 12.
Clicking Noises
The microwave NFA models (N8974A and N8975A) occasionally emit “clicking”
noises. This is caused by the NFA’s 3.0 GHz mechanical switch and is normal if
the measurement frequency range crosses over that point.
The NFA Always Powered On
If the NFA always turns on when power is applied, check the rear of the NFA.
There is an “always on” power mode switch that can be changed. Refer to the
Overview of the Rear Panel section of the User’s Guide for information on this
switch.
Chapter 1
11
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting an Inoperative NFA
Troubleshooting an Inoperative NFA
When an NFA appears to be faulty, for example, no display or inoperative fan,
there is often little evidence that points directly to the cause. This section provides
steps and solutions to typical failure modes.
Check the NFA Setup
Perform the steps in the section titled “Check the Basics” on page 9.
Initial Checks
Perform the following initial checks when first troubleshooting an inoperative
NFA.
Step 1. Check the fan is running.
1. If the fan is not running, refer to the section “If the Fan is Not Running” on
page 13.
2. If the fan is running, proceed to Step 2 if no other cause can be found.
Step 2. Check the power supplies.
1. To check the power supply voltages, refer to the section “Checking the Power
Supplies” on page 14.
2. If the power supply voltages all measure correctly, suspect a defective
processor, a defective LCD, or interface board.
Step 3. Check the display is on.
1. If the display is blank, refer to the section “Troubleshooting the LCD Display”
on page 18. Also verify that there is not a firmware error by performing the
“Bootrom Self-Test Check” on page 24.
Step 4. Checks the processor assembly can perform the following.
1. The LEDs along the top edge (shown in Figure 1-9) of the A4 Processor
Assembly must all be off. To check their functionality, power cycle the NFA.
The processor LEDs should all go on for a few seconds, then go off. If one or
more LEDs remains on, suspect the A4 Processor Assembly is defective. Refer
to the section “Troubleshooting the A4 Processor Assembly” on page 23.
12
Chapter 1
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting an Inoperative NFA
If the Line Fuse Has Blown
If the line fuse has blown, perhaps a nonstandard fuse with too low a current rating
was installed. If the line fuse still blows, suspect that the power supply assembly is
defective.
WARNING
For continued protection against fire hazard, replace fuse only with same type
and ratings, (5 A/250 V). The use of other fuses or materials is prohibited.
If the Fan is Not Running
CAUTION
The power supply may be hot if the instrument has been operating without the fan
running. Allow the instrument to cool down before troubleshooting.
1. If there is no display:
a. Unplug the line-power cord.
b. Change the switch at the rear of the NFA so the power is always on. Refer to
the Overview of the Rear Panel section of the User’s Guide for information
on this switch. This will bypass the front panel power switch.
c. If the fan still does not start, suspect a defective power supply assembly.
Refer to the section “Checking the Power Supplies” on page 14, to check
individual supply voltages.
d. If the fan starts, this indicates a problem with the front panel switch or the
circuitry to the front panel switch.
2. If there is a display:
a. Remove the NFA outer case. Refer to Chapter 6 for removal details.
b. Measure the fan voltage.
c. The fan voltage can be checked directly at the center of the fan where the
wires connect. The fan normally operates on a voltage ranging from −5 to
−16 Vdc depending on the fan speed needed, based on the temperature of
the NFA. As NFA temperature increases, fan voltage should become more
negative, increasing the speed of the fan.
If the correct voltage is present, suspect a defective fan.
If the voltage is not present, check the plug where the fan wires attach to the
power supply board. If this looks good, suspect a defective power supply.
Refer to Chapter 6 for information on how to remove the power supply.
Chapter 1
13
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting an Inoperative NFA
Checking the Power Supplies
To verify the power supply voltages using a power supply test board do the
following:
Step 1. Remove the NFA’s outer case and inner shield. See Chapter 6.
Step 2. Plug the test board (E4401-60235) into any available slot, except the slot for the
processor board.
Step 3. Observe the LEDs on the test board. See Figure 1-2.
Depending on the options installed in your NFA, you may need to remove one or
more option cards to allow access to the test points. Refer to Chapter 6 for removal
instructions.
The power supply test board LEDs will be On if the voltages are within 10% of
their specified voltages. Use a digital voltmeter to verify that the supplies are
within specifications. The voltages measured should be within the values listed in
Table 1-3.
NOTE
For accurate analog and digital measurements, use the analog common (ACOM)
and digital common (DCOM) test points respectively as listed in Table 1-3. These
points are clearly marked on the test board. See Figure 1-2.
WARNING
The NFA contains potentially hazardous voltages. Refer to the safety symbols
provided on the NFA, and in the general safety instructions in this guide,
before operating the unit with the cover removed. Ensure that safety
instructions are strictly followed. Failure to do so can result in severe or fatal
injury.
14
Chapter 1
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting an Inoperative NFA
Figure 1-2
Power Supply Test Board Voltage Locations
Table 1-3
Power Supply Tolerances
Test Point
Common
Power Supply
Specification
TP4 or TP10
TP13, ACOM
−15 V
−15.22 to −14.78 Vdc
TP5 or TP11
TP13, ACOM
−5 V
−5.07 to −4.93 Vdc
TP3 or TP9
TP13, ACOM
+5 V
+4.93 to +5.07 Vdc
TP2 or TP8
TP12, DCOM
+5.2 VD
+5.1 to +5.3 Vdc
TP1 or TP7
TP13, ACOM
+15 V
+14.78 to +15.22 Vdc
TP6
TP13, ACOM
+28 V
+26.04 to +29.96 Vdc
Chapter 1
15
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting an Inoperative NFA
The +15 V and –12.6 V supplies can be measured directly on the probe power
connector located on the front of the instrument. See Figure 1-3 for these test
points. If –12.6 V is within limits, it is a reasonably good indicator that –15 V is
within specifications.
Figure 1-3
Probe Power Connector Voltages
FRONT VIEW
+15V
-12.6V
If All Low Voltage Supplies Are Faulty
If all the power supplies are faulty, suspect a defective A5 power supply assembly.
Refer to Chapter 6 for removal instructions.
If Some Low Voltage Supplies Are Faulty
If some supplies are functioning while others are faulty, it is possible that one of
the assemblies in the NFA is loading the power supply low.
In this case it is necessary to sequentially remove the assemblies, taking care to
disconnect the line-power cord before removing any assembly. A logical first step
would be to unplug the RF assembly ribbon cable from the motherboard at the rear
of the instrument, see Figure 1-4. This disconnects the complete RF section
without having to remove it from the chassis. Refer to Chapter 6 for any other
assembly removal procedures.
After an assembly is disconnected or removed, plug the line-power cord back into
the NFA and remeasure the supply that was down. If it is still low, continue with
the assembly removal. If the supply is now up, suspect the last assembly removed
as being defective.
16
Chapter 1
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting an Inoperative NFA
Checking the Power Supplies Without a Test Board
If you do not have a power supply test board available, monitor the voltages at
A7J4 after you have removed the W4 ribbon cable. See Figure 1-4 and Figure 1-5.
The voltages measured should be within the values listed in Table 1-4.
Figure 1-4
Location of J4 Connector on Motherboard
J4
W4
Figure 1-5
Location of Test Points on J4 Connector
Table 1-4
Power Supply Voltage Levels at Test Points
Test Point
J4 Location
Power Supply (Vdc)
1
Pin 1
+28
2
Pin 2
+15
3
Pin 3
+5
4
Pin 4
+5 (Const.)
5
Pin 5
-5
6
Pin 6
-15
Chapter 1
17
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting the LCD Display
Troubleshooting the LCD Display
The only adjustment that can be made to the LCD display is the viewing angle.
This is found on the front panel of the NFA in the upper left corner. The following
procedure is a guide to troubleshoot the display.
Step 1. Ensure the NFA has gone through a full power-on sequence.
Step 2. Increase the display intensity by adjusting the viewing angle.
Step 3. If the display is not visible, connect an external VGA monitor to the rear panel
VGA output connector on the NFA. If the video information is not present on the
external VGA monitor, the most probable cause is the A4 processor assembly.
NOTE
It is possible that some multi-sync monitors may not be able to lock to the 60 Hz
sync pulse from the NFA.
Step 4. If the external VGA monitor is functioning, verify that the ribbon cables going to
and from the A1A1 front panel interface assembly are aligned properly and
securely plugged into the connectors.
Step 5. To determine whether the A1A2 LCD display or the A1A1 front panel interface
assembly is defective, remove the front frame assembly. See Chapter 6, “Replacing
Assemblies.”
Step 6. Troubleshoot the display by checking the inverter boards.The inverter board is
shown in Figure 1-6.
Refer to Table 1-5 and carefully measure the voltage coming into the inverter
board at CN1 pins 1-6 with a digital voltmeter.
WARNING
The inverter board contains high voltage for the backlights. Carefully remove
the inverter board by taking out the two screws securing it to the front frame,
then turn it over to access the CN1 connector.
Table 1-5
Measurement Locations and Expected Voltages
18
Measurement Location
Expected Voltage from A1A1 Front
Panel Interface
CN1 Pin 1
0 Vdc
CN1 Pin 2
0 Vdc
CN1 Pin 3
5 Vdc
CN1 Pin 4
5 Vdc
CN1 Pin 5
30 mV
CN1 Pin 6
2.5 Vdc
Chapter 1
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting the LCD Display
The display is not field-repairable, and must be replaced as an assembly. Refer to
Chapter 6 for part-number information.
Figure 1-6
LCD Troubleshooting Measurement Locations
If the voltages are correct, the most probable cause of failure is the A1A2 LCD
assembly.
NOTE
The display has two backlights to illuminate the LCD. If both backlights are faulty,
the screen will be dark. The backlights can be replaced individually. However, it is
unlikely that both backlights are faulty simultaneously. If one backlight is faulty,
the LCD illuminates but the darkness is noticeable, and you need to replace
A1A2DS1 or A1A2DS2. It is recommended that both backlights be replaced at the
same time.
Chapter 1
19
Troubleshooting the Noise Figure Analyzer (NFA)
Using the Internal Service-Diagnostic Routines
Using the Internal Service-Diagnostic Routines
The NFA has several routines which are helpful in diagnostics:
NOTE
•
Timebase (in Service Menu, password-protected).
•
Noise Source On or Off (in Service Menu, password-protected).
•
Align YTF (N8974A and N8975A models).
•
IF Test (in Service Menu, password-protected).
•
Write to SNS (in Service Menu, password-protected).
•
Restore System Defaults.
•
Front Panel Test (in Diagnostic menu).
The Service Menu is password protected. To access it, press the System key,
Service menu key. At the password prompt, enter −2010 and press Enter.
Timebase (in Service Menu)
This function allows adjustment of the coarse and fine digital to analog converters
(DACs) controlling the voltage-controlled crystal oscillator (VCXO) timebase
(OCXO, if Option 1D5 is installed). For more information on this refer to the
10 MHz Out Frequency Reference Adjustment test in the Calibration and
Performance Verification Guide.
The coarse DAC has a resolution of approximately 9 Hz per DAC count (for the
VCXO). The fine DAC has a resolution of approximately 1.2 Hz per DAC count
(for the VCXO). Any changes made to these DACs remain in effect until the NFA
power is Preset. To save the timebase DAC values stored in EEROM press the
Save menu key.
Noise Source On or Off (in Service Menu)
This function allows you to switch the +28V noise source drive on or off and
measure the voltage with a DVM.
•
To switch the +28V drive on, press the Noise Source On menu key. Measure
the voltage. The result should be within +28V ± 0.1V.
•
To switch the +28V drive off, press the Noise Source Off menu key. Measure
the voltage. The result should be within 0.0V ± 1.0V.
For more information on this refer to the Noise Source Supply Accuracy test in the
Calibration and Performance Verification Guide.
20
Chapter 1
Troubleshooting the Noise Figure Analyzer (NFA)
Using the Internal Service-Diagnostic Routines
Align YTF
NOTE
On models N8974A and N8975A where a problem occurs in the frequency range
greater than 3.0 GHz attempt to align the YTF before any disassembly.
This function allows you to align the tuning current of the YIG Tuned Filter (YTF)
against frequency. This is enabled by pressing Align YTF. To avoid an accidental
key press you must press Align YTF menu key twice.
When the YTF alignment routine is finished you must press
Save YTF Alignment to store the data to persistent memory. To avoid an
accidental key press you must press Save YTF Alignment menu key twice.
IF Test (in Service Menu)
This function is used by the factory and is not needed by any person repairing the
NFA.
Write to SNS (in Service Menu)
This function is used by the factory and is not needed by any person repairing the
NFA.
Restore System Defaults
Restore Sys Defaults resets the NFA to the original factory system default
configuration. It also performs an instrument preset. To access this function, press
the System key, the Restore Sys Defaults menu key. refer to the User’s Guide
for more information.
Use Restore Sys Defaults to return the NFA to a known “safe” state.
Chapter 1
21
Troubleshooting the Noise Figure Analyzer (NFA)
Using the Internal Service-Diagnostic Routines
Front Panel Test (in Diagnostic Menu)
This function allows you to verify the functionality of each front panel key (except
Preset). The number next to each key name increments once each time the key is
pressed. Rotating the RPG causes the number of pulses to be counted. Press Esc to
exit. See Figure 1-7 as an example of a typical display.
Figure 1-7
Example of Front Panel Test Display
22
Chapter 1
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting the A4 Processor Assembly
Troubleshooting the A4 Processor Assembly
If you suspect you have a problem caused by the A4 processor assembly, use the
following procedures to determine if A4 processor assembly must be replaced or if
it can be restored to normal operation.
NOTE
A4 processor assembly replacement can only be performed at an Agilent Service
Centre.
Initial Checks
Some steps reference other troubleshooting procedures which appear later in this
section.
Step 1. Verify the NFA product number, serial number, and firmware revision. Press
System, More 1 of 2, Show System. The display should be similar to Figure 1-8.
Figure 1-8
Example Show System Display
Step 2. Turn the NFA power off and reseat A4.
1. Referring to Figure 6-21 on page 174, remove the vibration support.
2. Referring to Figure 6-26 on page 181, remove the single screw (4) which
secures the processor assembly (8) to the chassis.
3. Carefully lift the A4 processor assembly until the assembly disengages from
the two motherboard connectors.
4. Carefully plug the processor assembly into the motherboard.
Chapter 1
23
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting the A4 Processor Assembly
5. Replace the single screw (4) to secure the A4 processor assembly to the
chassis. Turn the NFA power on.
6. If normal operation is not restored, continue with step 3.
Step 3. Perform the test described in “Bootrom Self-Test Check” on page 24.
Step 4. If proper operation has not been restored by following the preceding steps, replace
A4 processor assembly.
Bootrom Self-Test Check
When the NFA is powered-on, the bootrom performs several self-tests. Before
each self-test, the LEDs along the top edge of the A4 processor assembly light in a
pattern which shows the test to be performed. As tests succeed, the LED pattern
changes. If a test fails, the LED pattern remains in a state which corresponds to the
test that failed. If the display is not functioning, observing the LED pattern
provides information on the status of the self tests performed. Table 1-6 lists the
LED patterns and their associated tests:
1. Power up the NFA. Verify that LED DS1 is flashing, approximately, once every
second. If DS1 in continuously on or off, replace the A4 processor assembly.
Table 1-6
Self-Tests versus LED Pattern
LED Pattern
Self-Test Performed
D
S
1
D
S
7
D
S
13
D
S
11
D
S
9
D
S
12
D
S
10
D
S
8
Start of Test
1
1
1
1
1
1
1
1
Bootrom Flash EPROM Checksum
1
1
1
1
1
1
1
0
RAM used by Bootrom (destructive)
1
1
1
1
1
1
0
0
Remainder of RAM (non-destructive)
1
1
1
1
1
0
0
0
Main Firmware Checksum
1
1
1
0
0
0
0
0
All Tests Completed Successfully
0
0
0
0
0
0
0
0
2. Power cycle the NFA and observe the LEDs shown in Figure 1-9. If all the
LEDs do not light at the start of the test, the bootrom self-tests did not run. Turn
the NFA power off and reseat the bootrom, A4U77, shown in Figure 1-9 (The
A4U77 bootrom component is contained in a socket and should be inserted
fully). After this is checked, power on the NFA. If the LEDs still do not light,
replace the A4 processor assembly, as described in Figure 6-26 on page 181.
24
Chapter 1
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting the A4 Processor Assembly
Figure 1-9
Location of A4U77 Bootrom and LEDs
LEDs
U77
3. If the self-test indicates a RAM failure, perform the “Clearing Dynamic RAM”
procedure below.
Clearing Dynamic RAM
The RAM in the NFA can be cleared by setting switch 2 on A4S1 to the on
position. The RAM can also be cleared by the following procedure:
1. Turn the NFA power Off.
2. Press and hold the Esc and <-Prev keys simultaneously.
3. Turn the NFA power On and wait 5 seconds while continuing to hold the Esc
and <-Prev keys.
4. Release the Esc and <-Prev keys.
5. Cycle the NFA power. The entire RAM has been set to 0.
Chapter 1
25
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting the A6 Floppy Drive Assembly
Troubleshooting the A6 Floppy Drive Assembly
The A6 Floppy (A:) drive allows you to copy data to and from the NFA’s internal
(C:) drive.
If it fails to read or write data, perform one of the following procedures.
Step 1. Insert a noise source ENR data disk into the A: drive
Step 2. Upload the data from the A: drive to the C: drive.
For an explanation of the various file operations see the User’s Guide.
or
Step 1. Insert the firmware upgrade kit loader disk 1 into the floppy drive
See “Firmware Installation Procedure” on page 10. for guidance on this procedure.
Step 2. Power cycle the NFA.
If either of these operations fail, replace the A6 Floppy Drive Assembly and repeat
the procedure.
If the fault remains after the A6 Floppy Drive Assembly has been replaced, suspect
the A4 Processor assembly.
26
Chapter 1
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting the A7A1 GPIB Assembly
Troubleshooting the A7A1 GPIB Assembly
This assembly allows you to control the NFA from a computer that has a General
Purpose Interface Bus (GPIB). The GPIB assembly contains an IEEE-488 bus
connector. It also includes a 25-pin parallel interface connector for connection with
an IEEE 1284 cable to PCL3 or PCL5 compatible printers. The connectors are
shown in Figure 1-10.
The parallel interface connector allows the NFA to print either its display or a
system report.
Figure 1-10
Location of GPIB and Printer Connectors
Parallel
Printer Port
Main GPIB
Connector
Printer Faults
If you have a printer fault and you have confirmed the connections and cabling to
the printer are in good order. Suspect the A7A2 GPIB Assembly or the A4
Processor Assembly.
Perform the procedures in the section “Troubleshooting the A4 Processor
Assembly” on page 23 to confirm the A4 Processor Assembly is functioning. If
this is functioning, replace the suspected A7A2 GPIB Assemblies.
Chapter 1
27
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting the A7A1 GPIB Assembly
GPIB Faults and Errors
If you have a communication error when working remotely and you have
confirmed the connections and cabling have been checked. Suspect the A7A2
GPIB Assembly or the A4 Processor Assembly.
Perform the procedures in the section “Troubleshooting the A4 Processor
Assembly” on page 23 to confirm the A4 Processor Assembly is functioning.
If this is functioning, and you have the N2716A Software, confirm the suspected
A7A2 GPIB Assembly is at fault by performing the “Communicating with the
NFA using N2716A Software” on page 28.
If you do not have the N2716A Software and the A4 Processor Assembly is
functioning, replace the suspected A7A2 GPIB Assembly.
Communicating with the NFA using N2716A Software
If you are using the N2716A Performance Verification and Adjustment Software,
to attempt communication with the NFA. Ensure the correct model number is
entered and the address is set to 8. Using the Auto Detect command in the Run
window, press the Configure UUT key, followed by the Detect>> key, as
shown Figure 1-11.
Figure 1-11
This command ensures the NFA’s listen and talk commands are functioning
correctly and the A7A2 GPIB Assembly is working. The model number and serial
number are displayed.
If the A7A2 GPIB Assembly is faulty then an error message appears, similar to the
example shown in Figure 1-12. Replace the suspected A7A2 GPIB Assembly.
Figure 1-12
N2716A Displaying a GPIB Communication Error
28
Chapter 1
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting the A7A2 SIB Assembly
Troubleshooting the A7A2 SIB Assembly
The A7A2 SIB Assembly controls the following four functions:
1. The RS-232 interface.
This allows you to control your NFA from a computer using that type of
interface. It has an RS-232 9-pin connector (Agilent 5182-4794).
2. The LO GPIB interface.
This allows the dedicated control of an external LO by the NFA.
3. The +28V Noise Source Supply (pulsed).
This is supplied from this board to the BNC connector on the front panel. On
older models, the cable supplying the +28V to the noise source is two sections,
hence there is a connecting section in the card cage frame.
4. The SNS Connector interface.
This supplies the interface and associated hardware to control the SNS.
RS 232 Faults and Errors
Suspect the A7A2 SIB Assembly or the A4 Processor Assembly.
Perform the procedures in the section “Troubleshooting the A4 Processor
Assembly” on page 23 to confirm the A4 Processor Assembly is functioning. If
this is functioning, replace the suspected A7A3 SIB Assembly.
LO GPIB Faults and Errors
Suspect the A7A2 SIB Assembly or the A4 Processor Assembly.
Perform the procedures in the section “Troubleshooting the A4 Processor
Assembly” on page 23 to confirm the A4 Processor Assembly is functioning. If
this is functioning, replace the suspected A7A3 SIB Assembly.
Troubleshooting the +28V Noise Source supply
There are a number of checks that can be performed if there is a fault with the
+28V supply.
•
Visual Inspection of the LED A7A2DS2 on SIB Board, as shown in Figure
1-13. This LED should be flashing continuously, on or off. If this LED is not
flashing replace the A7A2 SIB Assembly.
Chapter 1
29
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting the A7A2 SIB Assembly
Figure 1-13
Location of A7A2DS2 LED
DS2 LED
•
Check the On and Off voltages. See the “Noise Source On or Off (in Service
Menu)” on page 20 for an explanation of this procedure. Check the voltage at
the A7A2J102 connector. If this does not work, suspect the A7A2 SIB
Assembly or A5 PSU.
On older models, the cable from the A7A2J102 connector to the +28V drive is
in two sections. Both sections need checked, as shown in Figure 1-14. If both
results are approximately 0V, suspect the cables or BNC connector on the front
panel.
30
Chapter 1
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting the A7A2 SIB Assembly
Figure 1-14
Location of +28V and SNS Cables1
+28V Noise
Source Cable
(Part 2)
SNS Cable
+28V Cable
Connector
•
If you have the N2716A Performance Verification and Adjustment Software, run
the +28V Noise Source Supply Accuracy Test. If you do not have the software,
run the +28V Noise Source Supply Accuracy Test in the Calibration and
Performance Verification Guide. If this test fails and the visual inspection of the
LED passed, check the calibration report values. If the results moderately out of
specification, suspect the A7A2 SIB Assembly.
Smart Noise Source (SNS) Faults and Errors
Suspect the A7A2 SIB Assembly or the A4 Processor Assembly.
Confirm the SNS cable and the SNS front panel connector are functioning.
NOTE
If you suspect the SNS or the interconnecting cable is faulty, refer to the SNS
Operating and Service Guide for further information.
If you are satisfied the fault is not caused by the SNS cable and the SNS front panel
connector. Perform the procedures in the section “Troubleshooting the A4
Processor Assembly” on page 23 to confirm the A4 Processor Assembly is
functioning. If this is functioning, replace the suspected A7A2 SIB Assembly.
1. Figure 1-14 shows the older cabling arrangement of using two parts for the +28V supply. If one of these sections
are faulty you can order the W28 cable and replace both sections.
Chapter 1
31
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting the A7A4 DSP Assembly
Troubleshooting the A7A4 DSP Assembly
This section applies to models, N8973A, N8974A, and N8975A only.
The Digital Sample Processing (DSP) Assembly is used when making the narrow
bandwidth measurements of: 2.0 MHz, 1.0 MHz, 400.0 KHz, 200.0 KHz, and
100.0 KHz.
NOTE
The 4.0 MHz bandwidth is measured with the A7A5 IF Assembly.
The A4 DSP Assembly is connected to the IF Board by the control ribbon cable
and the clock cable.
•
Power on the NFA and ensure that the DSP LEDs, shown in Figure 1-15,
initially flash ON then remain OFF. If this fails suspect the A4 DSP Assembly.
Replace the suspect A4 DSP Assembly.
•
If you have the N2716A Performance Verification and Adjustment Software, use
the Frequency Accuracy Test to determine whether the narrow bandwidth
measurements are functioning. If you do not have the software, run the
Frequency Accuracy Test in the Calibration and Performance Verification
Guide.
•
If the Frequency Accuracy test fails at the narrow bandwidths and passes at
4.0 MHz, suspect the A4 DSP Assembly or its interconnecting cables shown in
Figure 1-16.
Figure 1-15
32
Chapter 1
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting the A7A4 DSP Assembly
Figure 1-16
•
NOTE
Figure 1-17
Measure the clock signal on the cable input to A7A4P4. An example clock
signal is shown in Figure 1-17. The frequency is 12.5 MHz.
The clock signal may have some ringing effects. This is normal.
Typical Clock Signal
Chapter 1
33
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting the A7A5 IF Assembly
Troubleshooting the A7A5 IF Assembly
The A7A5 IF assembly is a selective 4.0 MHz wide Power Meter centered around
a 21.4 MHz input signal. On the Documentation and Software CD there are VEE
programs provided to help you troubleshoot the assembly.
You can check the following features on the IF Assembly:
•
The Clock signal at A7A5J102.
•
The IF Gain Control.
•
The bandwidth shape.
•
A noisy assembly.
The Clock Signal Check
Measure the clock signal on the cable A7A5J102. An example clock signal is
shown in Figure 1-18. If the clock signal is functioning, it suggests the PLD and
the firmware are functioning.
NOTE
The clock signal may have some ringing effects. This is normal.
Figure 1-18
Typical Clock Signal
34
Chapter 1
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting the A7A5 IF Assembly
IF Gain Control Check
Use the VEE program to check the attenuator steps.
Step 1. Remove the W31 cable from the A7A5J100 connector.
Step 2. Inject a 21.4 MHz signal from a Signal Generator into the J100 connector of the IF
Assembly.
Step 3. Set the amplitude value of the signal generator to display 0 dB on the VEE power
meter.
Step 4. Select a bank of attenuators and ensure the VEE power meter changes by the
correct amount.
NOTE
The change displayed on the VEE power meter is only indicative and does not
always display the exact value.
Step 5. Return the attenuator selection to 0 dB.
Step 6. Select the next bank of attenuators and repeat step 4 and step 5 until all five
attenuator banks have been checked.
If this test fails replace the A7A5 IF Assembly.
Bandwidth Shape Check
Use the VEE program to check the bandwidth selectivity of the IF Assembly by
sweeping the IF input frequency.
Step 1. Remove the W31 cable from the A7A5J100 connector.
Step 2. Inject a 21.4 MHz signal from a Signal Generator into the J100 connector of the IF
Assembly.
Step 3. Set the amplitude value of the signal generator to display 0 dB on the VEE power
meter. As shown in Figure 1-19.
Chapter 1
35
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting the A7A5 IF Assembly
Figure 1-19
Typical VEE display with IF Input Level Set to 0dB
Step 4. Set the Signal Generator to increment by 100 kHz.
Step 5. Sweep the Signal Generator’s frequency and monitor where the -3 dB point is
using the VEE power meter
Its level should be flat between 19.4 MHz and 23.4 MHz and start to cut off at
21.4 ± 2.0 MHz.
If this test fails change the A7A5 IF Assembly.
Noisy Assembly Check
Use the VEE program to check if the IF Assembly is noisy by monitoring its noise
figure at maximum gain and minimum gain.
Step 1. Remove the W31 cable from the A7A5J100 connector.
Step 2. Set all the attenuator banks to 0 dB and ensure the VEE power meter value is about
-21 ± 3.0 dB.
Step 3. Set all the attenuator banks to their maximum value and ensure the VEE power
meter value is about -55 ± 3.0 dB.
If this check fails to vary in value by the correct amount change the A7A5 IF
Assembly.
36
Chapter 1
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting the A7A5 IF Assembly
When replacing the IF Assembly
The IF Board contains an EEprom which holds unique detector linearity
calibration data. Each IF board is characterized during the manufacturing process.
The relevant calibration data is then stored.
NOTE
As the calibration data is unique to each IF Assembly, any characterized IF
Assembly can be fitted to any NFA. The IF Assembly is a modular replacement
therefore there is no re-programming required.
Setting up and Using the VEE Program
To run the VEE program you must first install the Agilent VEE run time
environment on a PC.
NOTE
You need an HP/Agilent GPIB card installed in your PC with the correct IO
libraries installed.
In the IO library, set the address to Logical Unit 7. If you do not have Agilent IO
libraries installed, install them using the iolibs.exe file provided on the CD in
directory IO Libraries.
Installing the VEE Runtme Environment
Use the following procedure to set up the VEE run time environment on your PC.
This enable you to run the if_diag.vxe program.
Step 1. Insert the CD in your PC’s disc drive.
Step 2. Go to the directory VEE Runtime Files.
Step 3. Double click the Setup.exe file.
Step 4. Follow the on-screen instructions.
Step 5. Ensure the NFA is powered on and a GPIB cable is connected from the PC.
Step 6. Ensure the NFA address is set to 8.
Step 7. Go to the directory IF Diag.
Step 8. To run the program double click the if_diag.vxe file
Your PC display is similar to Figure 1-20.
Chapter 1
37
Troubleshooting the Noise Figure Analyzer (NFA)
Troubleshooting the A7A5 IF Assembly
Figure 1-20
Typical VEE display at Initial Set Up.
Step 9. Follow the troubleshooting procedure IF Gain Control Check, Bandwidth Shape
Check, and/or Noisy Assembly Check.
Step 10. To exit the program click Quit
Running the VEE program
To run the program on subsequent occasions double
Step 1. Insert the CD in your PC’s disc drive.
Step 2. Ensure the NFA is powered on and a GPIB cable is connected from the PC.
Step 3. Ensure the NFA address is set to 8.
Step 4. Go to the directory IF Diag.
Step 5. To run the program double click the if_diag.vxe file
Your PC display is similar to Figure 1-20.
Step 6. Follow the troubleshooting procedure IF Gain Control Check, Bandwidth Shape
Check, and/or Noisy Assembly Check.
Step 7. To exit the program click Quit
38
Chapter 1
2
Troubleshooting the Front End and RF
Sections
Chapter 2
39
Troubleshooting the Front End and RF Sections
What You Will Find in This Chapter
What You Will Find in This Chapter
This chapter provides information on troubleshooting the RF and the front end
sections of the analyzer. It explains how to isolate problems and provides
procedures for troubleshooting common failures.
Recommended Test Equipment
To run the tests in this chapter you need the following test equipment.
Table 2-1
Recommended Test Equipment
Equipment Description
Critical specification for equipment
substitution
Model
Spectrum Analyzer
Frequency Range: 10 MHz to 26.5 GHz
E4407A
Frequency Accuracy (CW): 0.02%
Power Level Range: -55 dBm
Synthesized Sweeper
Frequency Range: 10 MHz to 26.5 GHz
83620/30/40/50B
Frequency Accuracy (CW): 0.02%
Power Level Range: -55 dBm
Recommended Connector Torque Settings
Table 2-2
Recommended Torque Settings
Type
Description
Precision
7mm
12 lb-in (136 N-cm.)
Precision
3.5mm
8 lb-in (90 N-cm)
SMA
5 lb-in (56 N-cm) Use the SMA wrench to connect male
SMA connectors to female precision 3.5min connectors.
Connections of male precision 3.5mm. connectors to female
SMA connectors can be made with the precision 3.5mm
torque wrench (8 lb-in).
Type-N
Type-N connectors may be connected finger tight. If a
torque wrench is used, 12 lb-in (136 N-cm) is
recommended.
40
Chapter 2
Troubleshooting the Front End and RF Sections
Checking the Measurement Path
Checking the Measurement Path
You can use the following tests in the Calibration and Performance Verification
Guide or the N2716A Service Software to determine whether the measurement path
is functioning and the NFA meets its published specifications.
•
Input VSWR.
•
Noise Figure Range and Accuracy.
•
Gain Measurement Uncertainty.
•
Instrument Noise Figure.
•
Measurement Jitter.
If any of these tests fail, follow the procedure applicable to your model of NFA and
measure the signal at the test points in the measurement path.
NOTE
If the measured signal fails, suspect the A8 RF section or loose interconnections
within the measurement path.
Chapter 2
41
Troubleshooting the Front End and RF Sections
Troubleshooting the A2 Front End and Input Stage
Troubleshooting the A2 Front End and Input Stage
This section applies to models, N8972A and N8973A (10 MHz - 3.0 GHz). It
provides techniques for isolating amplitude failures along the signal path through
to the A8 assembly.
The A8FL1 Low Pass Filter, the A8A5 Attenuator, and the A2 Front End assembly
can be verified as functioning correctly by performing the “RF Front End and Input
Stage Verification Procedure” on page 42. The example uses a 50.0 MHz signal,
you can change this to a frequency where you suspect there is a frequency
problem. This procedure proves the assemblies are working.
Figure 2-1
RF Front End Test Points
RF Front End and Input Stage Verification Procedure
Step 1. Inject a 50 MHz CW signal at –20 dBm into the RF input of the analyzer.
Step 2. Set the NFA to 50 MHz, fixed frequency by pressing Fixed Freq, 50, MHz.
NOTE
Leave the default input attenuation set to 0 dB. However, the attenuator’s
auto-range facility may have set the attenuation to a different value, you need to
take this into account when measuring beyond point (C).
Step 3. Set sweep to continuous by pressing Sweep (Cont).
Step 4. Wait 10 seconds to allow the NFA to completed a sweep.
Step 5. Set sweep to single by pressing Sweep (Single).
Step 6. Disconnect the semi-rigid cables at the various test points shown in Figure 2-1 and
monitor the result on a spectrum analyzer. The result can be compared with the
appropriate figures at the test point.
42
Chapter 2
Troubleshooting the Front End and RF Sections
Troubleshooting the A2 Front End and Input Stage
Test Point A
Figure 2-2 shows a typical signal at the input connector. There should be no loss or
distortion through this connector. If there is any doubt replace the connector.
Figure 2-2
Typical 50.0 MHz Signal at Input of A8FL1J1 - Test Point A
Test Point B
Figure 2-3 shows a typical signal after it has passed through the Low Pass filter.
There should be no loss or distortion through this filter at 50.0 MHz. You can
increase the frequency value and check that the filter attenuates the signal at
frequencies greater than 3.1 GHz, if you suspect this is leading to measurement
problems. If there is any doubt replace the filter.
Chapter 2
43
Troubleshooting the Front End and RF Sections
Troubleshooting the A2 Front End and Input Stage
Figure 2-3
Typical 50.0 MHz Signal at Input of A8A5J1 - Test Point B
Test Point C
Figure 2-4 shows a typical signal after it has passed through the Attenuator. If the
attenuation on the NFA is set to 0 dB, there should be no loss or distortion through
this attenuator at 50.0 MHz. You can also use this test point to verify the attenuator
is working correctly. A description of the process is provided in “Verifying the RF
Input Attenuator Driver Functionality” on page 77 and this needs modified when it
is applied to this test point. If there is any doubt replace the attenuator.
Figure 2-4
Typical 50.0 MHz Signal at Input of A2J1 - Test Point C
44
Chapter 2
Troubleshooting the Front End and RF Sections
Troubleshooting the A2 Front End and Input Stage
Test Point D
Figure 2-5 shows a typical signal after it has passed through the RF Front End. If
the attenuation on the NFA is set to 0 dB, there should be gain through the Front
End of approximately 25 dB. If there is any doubt replace the Front End.
Figure 2-5
Typical 50.0 MHz Signal at Output of A2J2 - Test Point D
Chapter 2
45
Troubleshooting the Front End and RF Sections
Troubleshooting the A3 Microwave Front End, A2 Front End, and Input Stage
Troubleshooting the A3 Microwave Front End, A2 Front
End, and Input Stage
This section applies to models, N8974A and N8975A (10 MHz - 26.5 GHz). It
provides techniques for isolating amplitude failures along the signal path through
to the A8 assembly.
The A8FL1 Low Pass Filter, the A8A5 Attenuator, and the A2 Front End assembly
can be verified as functioning correctly by performing the “RF Front End and Input
Stage Verification Procedure” on page 42. The example uses a 50.0 MHz signal,
you can change this to a frequency where you suspect there is a frequency
problem. This procedure proves the assemblies are working.
NOTE
The A3 microwave front end assembly has a fan, ensure this is turning when the
NFA is switched on.
Figure 2-6
Microwave Models Front End Points
46
Chapter 2
Troubleshooting the Front End and RF Sections
Troubleshooting the A3 Microwave Front End, A2 Front End, and Input Stage
RF Front End and Input Stage “Quick Check” Verification
Procedure in Low Band
Step 1. Inject a 50 MHz CW signal at –20 dBm into the RF input of the analyzer.
Step 2. Set the NFA to 50 MHz, fixed frequency by pressing Fixed Freq, 50, MHz. Leave
the default input attenuation set to 0 dB.
Step 3. Set sweep to continuous by pressing Sweep (Cont).
Step 4. Wait 10 seconds to allow the NFA to completed a sweep.
Step 5. Set sweep to single by pressing Sweep (Single).
Step 6. Disconnect the semi-rigid cables at the various test points shown in Figure 2-6 and
monitor the result on a spectrum analyzer. The result can be compared with the
appropriate figures at the test point.
Test Point A
Figure 2-7 shows a typical signal at the ≤ 3.0 GHz output connector of the switch.
There should be no loss or distortion through this switch. If there is any doubt
replace the A3 assembly.
Figure 2-7
Typical 50.0 MHz Signal at Input of A8FL1J1 - Test Point A
Chapter 2
47
Troubleshooting the Front End and RF Sections
Troubleshooting the A3 Microwave Front End, A2 Front End, and Input Stage
Test Point B
Figure 2-8 shows a typical signal after it has passed through the Low Pass filter.
There should be no loss or distortion through this filter at 50.0 MHz. You can
increase the frequency value and check that the filter attenuates the signal at
frequencies greater than 3.1 GHz, if you suspect this is leading to measurement
problems. If there is any doubt replace the filter.
Figure 2-8
Typical 50.0 MHz Signal at Input of A8A5J1 - Test Point B
Test Point C
Figure 2-9 shows a typical signal after it has passed through the Attenuator. If the
attenuation on the NFA is set to 0 dB, there should be no loss or distortion through
this attenuator at 50.0 MHz. However, the example Figure 2-9 the NFA has
auto-ranged the attenuator to 25 dB, hence the signal loss of 15 dB.
You can also use this test point to verify the attenuator is working correctly. A
description of the process is provided in “Verifying the RF Input Attenuator Driver
Functionality” on page 77 and this needs modified when it is applied to this test
point. If there is any doubt replace the attenuator.
48
Chapter 2
Troubleshooting the Front End and RF Sections
Troubleshooting the A3 Microwave Front End, A2 Front End, and Input Stage
Figure 2-9
Typical 50.0 MHz Signal at Input of A2J1 - Test Point C
Test Point D
Figure 2-10 shows a typical signal after it has passed through the RF Front End. If
the attenuation on the NFA is set to 0 dB, there should be gain through the Front
End of approximately 10 dB. If there is any doubt replace the A2 Front End.
Figure 2-10
Typical 50.0 MHz Signal at Output of A2J2 - Test Point D
Chapter 2
49
Troubleshooting the Front End and RF Sections
Troubleshooting the A3 Microwave Front End, A2 Front End, and Input Stage
Quick Check RF Procedure for High Bands
Step 1. Inject a 4.7 GHz CW signal at –10 dBm into the RF input of the analyzer.
Step 2. Set the NFA to 4.7 GHz, fixed frequency, by pressing Fixed Freq, 4, ., 7,GHz.
Ensure the input attenuation set to the default 0 dB.
Step 3. Set sweep to continuous by pressing Sweep (Cont).
Step 4. Wait 10 seconds to allow the NFA to completed a sweep.
Step 5. Set sweep to single by pressing Sweep (Single).
Step 6. Disconnect the semi-rigid cables at the various test points shown in Figure 2-6 and
monitor the result on a spectrum analyzer. The result can be compared with the
appropriate figures at the test point.
Test Point E
Figure 2-11 shows a typical signal at the > 3.0 GHz output connector of the switch.
There should be no loss or distortion through this switch. If there is any doubt
replace the A3 assembly.
Figure 2-11
Typical 4.7 GHz Signal at Input of A3J4 - Test Point E
50
Chapter 2
Troubleshooting the Front End and RF Sections
Troubleshooting the A3 Microwave Front End, A2 Front End, and Input Stage
Test Point F
Figure 2-12 shows a typical signal after it has passed through the microwave Front
End. If the attenuation on the NFA is set to 0 dB, there should be gain through the
Front End of approximately 25 dB. If there is any doubt replace the A3 Front End.
Figure 2-12
Typical 4.7 GHz Signal at Input of A8A6J3 - Test Point F
Chapter 2
51
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Verifying the A8 RF Section Performance
This section applies to models, N8972A and N8973A (10 MHz - 3.0 GHz). It
provides techniques for isolating amplitude failures along the signal path.
The RF section downconverts the NFA’s input energy to the final IF of 21.4 MHz.
You can troubleshoot the RF section by injecting a 50.0 MHz CW signal at a power
level of –20 dBm to the RF input of the NFA. The 21.4 MHz downconverted IF
signal is the input level minus the input attenuation. There are three conversions
made in the NFA. Refer to Figure 2-13 for two examples of downconversion: one
with an input frequency of 1.0 GHz and one with an input frequency of 50.0 MHz.
Figure 2-13
Downconversion Examples in the RF Section
Quick A8 Troubleshooting Procedure
Use this procedure to quickly verify if the A8 is working. If this fails go to the
“Detailed A8 RF Troubleshooting Procedure” on page 54 for more troubleshooting
information.
Step 1. Inject a 50 MHz CW signal at –20 dBm into the analyzer’s RF input.
Step 2. Set the NFA to 50 MHz, fixed frequency by pressing Fixed Freq, 50, MHz. Leave
the default input attenuation set to 0 dB
Step 3. Set sweep to continuous by pressing Sweep (Cont).
Step 4. Wait 10 seconds to allow the NFA to completed a sweep.
Step 5. Set sweep to single by pressing Sweep (Single).
Step 6. Disconnect the flexible gray cable (W31) going into the A7A5 IF assembly at
A7A5J2.
Step 7. Connect a calibrated spectrum analyzer to this flexible gray cable (W31) and
measure the 21.4 MHz output from the RF section.
If this is operating properly, the signal out of the RF section should be similar to
Figure 2-14 spectrum analyzer’s display showing a 21.4 MHz at –15 dBm signal.
52
Chapter 2
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Figure 2-14
Typical 21.4 MHz RF Output to IF Input - A7A5J2
NOTE
If your signal level is too high or too low, check the input attenuation using the
process described in “Verifying the RF Input Attenuator and the Second Converter
Switch Logic” on page 76. The signal amplitude problem may be the result of a
defective A8A5 input attenuator or the attenuator logic from A8A1A1
Reference/Third Converter.
Another Quick Check using the 10.0 MHz Out Frequency Reference
Accuracy Test
If you are using the Calibration and Performance Verification Guide or the
N2716A Service Software, run the 10.0 MHz Out Frequency Reference Accuracy
Test to determine whether the RF is functioning within its published specification.
Figure 2-22 shows a typical 10.0 MHz signal.
NOTE
Ensure the NFA has been allowed to warm up for 60 minutes.
If the signal is not present check the RF assembly by performing the “Quick A8
Troubleshooting Procedure” on page 52 to verify this suspicion.
If the signal is out of specification, run the 10.0 MHz Out Frequency Reference
Adjustment to perform the adjustment.
Chapter 2
53
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Detailed A8 RF Troubleshooting Procedure
Use this procedure to isolate the failing assembly, use the instrument settings as
stated in “Quick A8 Troubleshooting Procedure” on page 52, then refer to Table
2-3, Figure 2-15, and Figure 2-16 to measure the measurement points throughout
the RF section. The Measurement Point column of the Table 2-3 corresponds to the
points shown in Figure 2-15, and Figure 2-16. The Expected Measured Signal
column references figures that illustrate the signal expected at that measurement
point.
Table 2-3
RF Section Measurement Points
Signal
Description
Measurement
Pointa
Expected
Frequency
Expected Level
Expected
Measured
Signalb
Notes
first IF Output
A
3921.4 MHz
−18.2 dBm
Figure 2-17
A8A1A2 has
~3.2 dB of loss.
second IF
Output
B
321.4 MHz
−23.5 dBm
Figure 2-18
A8A2 has ~4.5 dB
of loss.
RF Input
C
50 MHz
−16.0 dBm
Figure 2-19
A2 has ~5 dB of
gain.
second LO
Input
D
600 MHz
+3 dBm
Figure 2-20
Out of A8A1A1
(through A7A9 with
Option 120)
second LO
Multiplied
E
Block Diagram
only
3600 MHz
−16.0 dBm
Figure 2-21
Out of A8A2J5 LO
Test Port
10 MHz
Reference
F
10 MHz
+6 dBm
Figure 2-22
Rear Panel 10 MHz
Ref. Out
a. To locate the measurement points, refer to Figure 2-15 and Figure 2-16.
b. To see the signal expected at each measurement point, reference the figures in this column.
54
Chapter 2
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Figure 2-15
RF Section Measurement Points (N8972A and N8973A
Figure 2-16
RF Section Block Diagram (N8972A and N8973A)
Chapter 2
55
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Figure 2-17
Typical first IF Output - A8A1A2J3 - Measurement Point A
Figure 2-18
Typical 321.4 MHz second IF Output - A8A2J2 - Measurement Point B
56
Chapter 2
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Figure 2-19
Typical 50.0 MHz RF Input - A8A1A2J1 - Measurement Point C
Figure 2-20
Typical 600.0 MHz second LO Output - A8A1A1P1 - Measurement Point D
Chapter 2
57
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Figure 2-21
Typical 3600 MHz second LO Test Port - A8A2J5 - Measurement Point E
Figure 2-22
Typical 10 MHz Reference Output- Measurement Point F
58
Chapter 2
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Verifying the A8 RF Section Performance
This section applies to models, N8974A and N8975A (10 MHz - 26.5 GHz). It
provides techniques for isolating amplitude failures along the signal path.
The RF section downconverts the analyzer input signal to the final IF of 21.4 MHz.
You can troubleshoot the RF section by injecting a 50 MHz CW signal at –20 dBm
to the RF input of the analyzer. The 21.4 MHz downconverted IF signal will be the
input level minus the input attenuation. There are three conversions made in the A8
RF Assembly, as shown in Figure 2-13.
NOTE
A7A3 Frequency Extension assembly replacement can only be performed at an
Agilent Service Centre
Quick Troubleshooting Procedure in Low Band
NOTE
Low Band refers to frequencies less than or equal to 3.0 GHz.
Use this procedure to quickly verify if the A8 is working. If this fails go to the
“Detailed Troubleshooting Procedure in Low Band” on page 61 for more
troubleshooting information.
Step 1. Inject a 50 MHz CW signal at –20 dBm into the RF input of the analyzer.
Step 2. Set the NFA to 50 MHz, fixed frequency by pressing Fixed Freq, 50, MHz. Leave
the default input attenuation set to 0 dB.
Step 3. Set sweep to continuous by pressing Sweep (Cont).
Step 4. Wait 10 seconds to allow the NFA to completed a sweep.
Step 5. Set sweep to single by pressing Sweep (Single).
Step 6. Disconnect the flexible gray cable (W31) going into the A7A5 IF assembly at
A7A5J2.
Step 7. Connect a calibrated spectrum analyzer to the flexible gray cable (W31) and
measure the 21.4 MHz output from the RF section.
If the RF section is operating properly, the spectrum analyzer’s display should be
similar to Figure 2-23 showing a 21.4 MHz at –2 dBm signal out of the RF section.
Chapter 2
59
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Figure 2-23
Typical 21.4 MHz third IF Output
NOTE
If the signal amplitude is too high or too low, check the input attenuation using the
process described in “Verifying the RF Input Attenuator and the Second Converter
Switch Logic” on page 76. The signal amplitude problem may be the result of a
defective A8A5 input attenuator or the attenuator logic from A8A1A1
Reference/Third Converter.
Additional Quick Troubleshooting Information
•
If you notice a frequency response problem, visually inspect the RF input
connector for mechanical integrity. Read the Calibration and Performance
Verification Guide appendix called Caring for Connectors for further advice.
•
If the analyzer has a frequency response problem you can inject the frequency
of interest, set the analyzer to that fixed frequency value, and monitor the
21.4 MHz IF signal level for abnormalities on the calibrated spectrum analyzer.
•
If you have excessive loss through the RF section, see “Detailed
Troubleshooting Procedure in Low Band” on page 61 to help confirm the A8 is
the defective assembly.
60
Chapter 2
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Detailed Troubleshooting Procedure in Low Band
Use this procedure to isolate the failing assembly. Refer to Table 2-4, Figure 2-24,
and Figure 2-25 to measure the measurement points throughout the RF section.
The Measurement Point column of the Table 2-3 corresponds to the points shown
in Figure 2-24, and Figure 2-25. The Expected Measured Signal column references
figures that illustrate the signal expected at that measurement point.
Step 1. Inject a 50 MHz CW signal at –20 dBm into the RF input of the analyzer.
Step 2. Set the NFA to 50 MHz, fixed frequency by pressing Fixed Freq, 50, MHz.
Leave the default input attenuation set to 0 dB. However, the attenuator’s
auto-range facility may have set the attenuation to a different value, you need to
take this into account when making measurement as it may effect the result.
NOTE
Step 3. Set sweep to continuous by pressing Sweep (Cont).
Step 4. Wait 10 seconds to allow the NFA to completed a sweep.
Step 5. Set sweep to single by pressing Sweep (Single).
Table 2-4
RF Section Low Band Measurement Points
Signal
Description
Measurement
Pointa
Expected
Frequency
Expected
Level
Expected
Measured
Signalb
Notes
first IF Output
A
3921.4 MHz
−18.2 dBm
Figure 2-26
A8A1A2 has ~3.2 dB of
loss.
second IF
Output
B
321.4 MHz
−21.5 dBm
Figure 2-27
A8A2 has ~4.5 dB of loss.
RF Input
C
50 MHz
−16.5 dBm
Figure 2-28
Out of A8A3
second LO
Input
D
600 MHz
+1 dBm
Figure 2-29
Out of A8A1A1 (through
A7A9 with Option 120)
second LO
Multiplied
E
Block Diagram
only
3600 MHz
−13.5 dBm
Figure 2-30
Out of A8A2J5
LO Test Port
10 MHz
Reference
F
10 MHz
+5 dBm
Figure 2-31
Rear Panel 10 MHz
Ref. Out
first LO Output
H
3971.4 MHz
0 dBm
Figure 2-32
Out of A8A1A2
a. To locate the measurement points, refer to Figure 2-24 and Figure 2-25.
b. To see the signal expected at each measurement point, reference the figures in this column.
Chapter 2
61
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Figure 2-24
RF Section Low Band Measurement Points
62
Chapter 2
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Figure 2-25
RF Section Low Band Block Diagram (N8974A and N8975A)
Chapter 2
63
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Figure 2-26
Typical first IF Output - A8A1A2J3 - Measurement Point A
Figure 2-27
Typical 321.4 MHz second IF Output - A8A2J2 - Measurement Point B
64
Chapter 2
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Figure 2-28
Typical 50.0 MHz RF Input - Measurement Point C
Figure 2-29
Typical 600 MHz second LO − A8A1A1P1 - Measurement Point D
Chapter 2
65
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Figure 2-30
Typical 3600 MHz A8A2J5 LO Test Port - Measurement Point E
Figure 2-31
Typical 10.0 MHz Reference Output − A8A1A1 - Measurement Point F
66
Chapter 2
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Figure 2-32
Typical first LO Output − A8A1A2J5 - Measurement Point H
Chapter 2
67
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Quick Troubleshooting Procedure in High Bands
NOTE
High Band refers to frequencies greater than 3.0 GHz.
Use this procedure to quickly verify if the A8 is working. If this fails, go to the
“Detailed RF Troubleshooting for High Bands” on page 70 for more
troubleshooting information.
Step 1. Inject a 4.7 GHz CW signal at –10 dBm into the RF input of the analyzer.
Step 2. Set the NFA to 4.7 GHz, fixed frequency, by pressing Fixed Freq, 4, ., 7, GHz.
Ensure the input attenuation is set to the default 0 dB.
Step 3. Set sweep to continuous by pressing Sweep (Cont).
Step 4. Wait 10 seconds to allow the NFA to completed a sweep.
Step 5. Set sweep to single by pressing Sweep (Single).
Step 6. Disconnect the flexible gray cable (W31) going into the A7A5 IF assembly at
A7A5J2.
Step 7. Connect a calibrated spectrum analyzer to the flexible gray cable (W31) and
measure the 21.4 MHz output from the RF section.
If the RF section is operating properly, the spectrum analyzer’s display should be
similar to Figure 2-33 showing a 21.4 MHz at 11 dBm signal out of the RF section.
Figure 2-33
Typical 21.4 MHz Output - From A8A1A1 to A7A5
68
Chapter 2
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
NOTE
If the signal amplitude is too high or too low, check the input attenuation using the
process described in “Verifying the RF Input Attenuator and the Second Converter
Switch Logic” on page 76. The signal amplitude problem may be the result of a
defective A8A5 input attenuator or the attenuator logic from A8A1A1
Reference/Third Converter.
Additional Quick Troubleshooting Information
•
If you notice a frequency response problem, visually inspect the RF input
connector for mechanical integrity. Read the Calibration and Performance
Verification Guide appendix called Caring for Connectors for further advice.
•
If the analyzer has a frequency response problem you can inject the frequency
of interest, set the analyzer to that fixed frequency value, and monitor the
21.4 MHz IF signal level for abnormalities on your calibrated spectrum
analyzer.
•
If you have excessive loss through the RF section, see “Detailed
Troubleshooting Procedure in Low Band” on page 61 to help confirm the A8 is
the defective assembly.
Chapter 2
69
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Detailed RF Troubleshooting for High Bands
Use this procedure to isolate whether the A8A6 YTF/Mixer assembly or the A8A4
LO Amp/IF switch assembly is failing.
Step 1. Inject a 4.7 GHz CW signal at –10 dBm into the RF input of the analyzer.
Step 2. Set the NFA to 4.7 GHz, fixed frequency, by pressing Fixed Freq, 4, .,7, GHz.
Ensure the input attenuation set to the default 0 dB.
Step 3. Set sweep to continuous by pressing Sweep (Cont).
Step 4. Wait 10 seconds to allow the NFA to completed a sweep.
Step 5. Set sweep to single by pressing Sweep (Single).
Refer to Table 2-5, Table 2-6, Figure 2-34, and Figure 2-35 to measure the
measurement points throughout the RF section. The Measurement Point column of
the Table 2-6 corresponds to the points shown in Figure 2-24, and Figure 2-25. The
Expected Measured Signal column references figures that illustrate the signal
expected at that measurement point.
With the instrument settings stated in the above steps, use a calibrated spectrum
analyzer to measure the signals in Table 2-6.
NOTE
The first LO originating from the A8A1A2 LO board is heavily attenuated in the
A8A4 LO Amp/ IF switch assembly when the analyzer is tuned to frequencies
≤ 3.0 GHz. At such times the A8A6 YTF/Mixer assembly is internally and
electronically bypassed.
However, when the analyzer is tuned higher than 3.0 GHz, the A8A6 YTF/Mixer
assembly is used for down conversion and high LO power is supplied to the A8A6
YTF/Mixer for conversion efficiency. At such times the A8A4 LO Amp/IF switch
is amplifies the first LO.
The first LO modulator drive voltage originates on the A7A4 Frequency Extension
board. Before changing the A8A6 YTF/Mixer assembly or the A8A4 LO Amp/IF
switch, first verify the switching logic as shown in Table 2-5.
Table 2-5
A8A6 YTF/Mixer Switching Logic
70
Measurement Point
Frequencies
≤ 3.0 GHz
Frequencies
> 3.0 GHz
A7A4J2 pin 9
0V
5V
A7A4J2 pin 20
5V
0V
A7A4J2 pin 21
5V
0V
Chapter 2
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
NOTE
A8A4 LO Amp/ IF switch assembly replacement can only be performed at an
Agilent Service Centre
Table 2-6
RF Section High Band Measurement Points
Signal
Description
Measurement
Pointa
Expected
Frequency
Expected
Level
Expected
Measured
Signalb
Notes
first IF Output
A
321.4 MHz
2 dBm
Figure 2-36
A8A6 has ~12 dB of loss.
first IF Output
B
321.4 MHz
8 dBm
Figure 2-37
A8A4 amplifies the 321.4 MHz
IF by ~6.5 dB.
first LO Output
Refer to
Figure 2-24
Point C
3971.4 MHz
−8 dBm
Figure 2-38
Out of A8A1A2
first LO Output
D
5021.4 MHz
+11 dBm
Figure 2-39
Out of A8A4 in high bands
ONLY. LOIS amplifies the input
by ~16 dB
a. To locate the measurement points, refer to Figure 2-34 and Figure 2-35.
b. To see the signal expected at each measurement point, reference the figures in this column.
Chapter 2
71
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Figure 2-34
RF Section High Band Measurement Points
72
Chapter 2
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Figure 2-35
RF Section High Band Block Diagram N8974A and N8975A
Chapter 2
73
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Figure 2-36
Typical 321.4 MHz IF High Band - A8A6J1 - Measurement Point A
Figure 2-37
Typical 321.4 MHz Internal IF - A8A4J7 - Measurement Point B
74
Chapter 2
Troubleshooting the Front End and RF Sections
Verifying the A8 RF Section Performance
Figure 2-38
Typical first LO - A8A1A2J5 - Measurement Point C
Figure 2-39
Typical High Band LO - A8A4J2 - Measurement Point D
Chapter 2
75
Troubleshooting the Front End and RF Sections
Verifying the RF Input Attenuator and the Second Converter Switch Logic
Verifying the RF Input Attenuator and the Second
Converter Switch Logic
This section shows how to verify the driver circuitry from the A8A1A1 reference
third converter for the attenuator and second converter are functioning properly. It
applies to all models.
Step 1. Remove the outer case as described in Chapter 6.
Step 2. Remove the front frame assembly as described in Chapter 6.
Step 3. Unplug the attenuator/second converter cable (1) from the A8A1A1 assembly, and
replace it with the test cable (2) for the attenuator/second converter driver test
board (E4401-60240), as shown in Figure 2-40.
Step 4. Reconnect the front-panel interface cable (3).
Step 5. Loosely re-attach the front frame with the test board cable dressed out the bottom
of the NFA as shown in Figure 2-40.
Step 6. Switch on the NFA and observe the test board LEDs.
Figure 2-40
Connecting the Attenuator/second Converter Driver Test Board
76
Chapter 2
Troubleshooting the Front End and RF Sections
Verifying the RF Input Attenuator and the Second Converter Switch Logic
Verifying the RF Input Attenuator Driver Functionality
You can verify that the correct driver signals are present by stepping the attenuator
through its various settings. To access the attenuator menu keys set the NFA up as
follows:
NOTE
The frequency setting must be ≤ 3.0 GHz if you are performing the check on the
N8974A and N8975A models.
Step 1. Press the Sweep key
Step 2. Press the Manual Meas menu key.
Step 3. Select the Manual State (On) menu keys.
Step 4. Press the Press the RF Att (Fixed) menu keys.
Step 5. Press the Press the More 1 of 2 menu keys.
Step 6. Press the Fixed RF Att menu keys.
Step 7. As you change the attenuation settings, the LEDs on the test board illuminate
according to Table 2-7.
NOTE
The 0 dB to 10 dB attenuation is controlled by the A2 Front End board.
The state indicator shown in Table 2-8 is organized such that the attenuator
sections are either switched In (Red) or switched Out (Green). The +28 V LED
(Yellow) should be On whenever the instrument is powered up.
For example, if you have an attenuation setting of 35 dB, the attenuation sections 2
and 3 would be switched In (Red) and section 1 would be switched Out (Green).
Table 2-7
Attenuator/second Converter Test Board Logic Matrix
Attenuation Section
Chapter 2
Attenuation Value
Section 5
n/a (always Red)
Section 4
n/a (always Green)
Section 3
5 dB
Section 2
20 dB
Section 1
10 dB
77
Troubleshooting the Front End and RF Sections
Verifying the RF Input Attenuator and the Second Converter Switch Logic
Table 2-8
Drive Section and State Indicator
LED
State
Drive Section
Red
In
Section 5
Green
Out
Section 4
Green
Out
Section 3
Red
In
Green
Out
Red
In
Green
Out
Red
In
Yellow
Section 2
Section 1
+28 Volts
Verifying the second Converter Switch Logic
You can verify the correct driver signals are present by sweeping from low band
into high band. Press the Frequency key, change the start frequency from
10.0 MHz and sweep it to a stop frequency to 6.0 GHz. As the analyzer sweeps
through 3.0 GHz, the second converter PIN switch LEDs will reflect the change as
shown in Table 2-9.
NOTE
It may be helpful to use a slow sweep time.
There is only be a change from low band to high band if the instrument frequency
range goes above 3.0 GHz. Therefore, for N8972A and N8973A models
(≤ 3.0 GHz), the low band and drain supply LEDs should remain on at all times.
Table 2-9
78
Second Converter PIN Switch and Drain Supply
Band
Pin Switch
Drain Supply
≤ 3.0 GHz
Low (Green)
On (Yellow)
> 3.0 GHz
High (Red)
Off
Chapter 2
3
Error Messages
Chapter 3
79
Error Messages
What You Will Find in This Chapter
What You Will Find in This Chapter
This chapter explains the error messages that can appear on the front panel display
or be transmitted over an interface bus.
80
Chapter 3
Error Messages
Error Messages
Error Messages
The analyzer can generate various messages that appear on the display during
operation. There are three types of messages.
•
Informational Messages provide information that requires no intervention.
These messages appear in the status line at the bottom of the display, in green if
you have a color display. The message remains until you preset the analyzer,
press ESC, or another message is displayed in the status line.
•
User Error Messages appear when an attempt has been made to set a parameter
incorrectly or an operation has failed (such as saving a file). These messages
are often generated during remote operation when an invalid programming
command has been entered. These messages appear in the status line at the
bottom of the display, in yellow if you have a color display. The message
remains until you preset the analyzer, press ESC, or another message is
displayed in the status line. A summary of the last 10 error messages may be
viewed by pressing, System then Show Errors. When generated by activity on
the remote interface, the messages are output to the remote bus. When output to
the remote interface, they are preceded by an error number. Note that the error
number is not displayed under the System, Show Errors key sequence.
•
Pop-up Messages indicate a condition that may require intervention. They
display in the middle of the display in a framed box. The message remains until
the appropriate intervention has taken place or the condition is corrected.
Chapter 3
81
Error Messages
Error Messages
Informational Messages
The following messages provide information that requires no intervention. These
type of messages are in green. The information provided in brackets, for example
<filename> or <name> is a variable that represents a specific input provided
previously.
<filename> file loaded
The filename indicated has been successfully loaded.
<filename> file saved
The filename indicated has been successfully saved.
<filename> file copied
The filename indicated has been successfully copied.
<filename> file deleted
The filename indicated has been successfully deleted.
<filename1> file renamed to <filename2>
Filename1 has been successfully renamed to filename2.
Duplicate frequency entered in table, old
entry replaced
A duplicate entry was made in either the ENR table, frequency
list, limit line table or loss table. The previous entry is replaced
with the new entry.
Each result type selected must differ from
all others
An attempt was made to select the same result type for both of
the two displayed result types.
Volume <name> formatted
The indicated disk has been successfully formatted.
82
Chapter 3
Error Messages
Error Messages
Zoom active in graph mode only
The
key is only active when display format is set to
Graph.
Zoom inactive when showing combined graph
The
key is not active if the display format is set to
Combined.
User cal now valid
Previously invalidated user cal is now valid due to change of
instrument parameter(s).
Invalid frequency list for measurement mode
A frequency within the frequency list cannot be used to make a
measurement in the current mode.
ENR table will be extrapolated
The measurement requires ENR values beyond the limits of the
existing ENR table.
User cal will be interpolated
For a corrected measurement, the measurement frequencies do
not coincide with the user cal frequencies.
Memory trace invalidated
A change of instrument parameter has caused the memory trace
to be invalidated (removed from screen and no longer
selectable).
Maximum number of entries in table reached
The maximum number of entries in the ENR table, frequency
list or limit line table has been reached.
Chapter 3
83
Error Messages
Error Messages
Error Queues
When a user-error condition occurs in the instrument as a result of SCPI activity, it
is reported to both the front-panel display-error queue and the SCPI (remote
interface) error queue. If it is a result of front-panel activity it reports to the front
panel display error queue, and may also report to the SCPI error queue depending
on the error. These two queues are viewed and managed separately.
Error messages have a signed error number followed by some error text in double
quotes. Negative error numbers are for predefined SCPI errors, for example error
-350, “Queue overflow” which is issued if an error occurs when the error queue is
already full. Positive errors are instrument specific.
The query used to get the head of the error queue is SYSTEM:ERROR:NEXT?. It
can only retrieve one error at a time.
The special error message +0, “No error” indicates that the error queue is empty.
You can query the error queue as often as you like, when it is empty you just keep
getting +0, “No error”.
A single command or query can generate more than one error message. For this
reason it is best to drain the error queue after each command or query. If not, you
will lose track of what commands caused what errors.
Errors can occur that are not directly related to the last command issued. You can
use status information to find out if your command generated an error. Status
information can also tell you if some other type of error has occurred. However, if
the status information indicates there are different types of error in the error queue,
you cannot know which of the errors was caused by the last command unless it is
obvious from the error itself.
84
Chapter 3
Error Messages
Error Messages
Table 3-1
Characteristics of the Error Queues
Characteristic
Front Panel Display
Error Queue
SCPI Remote Interface
Error Queue
Capacity (#errors)
10
30
Overflow Handling
Circular (rotating).
Drops oldest error as new error
comes in.
Linear, first-in/first-out.
Replaces newest error with:
-350,Queue overflow
Viewing Entries
Press: System, Show Errors
Use SCPI query
SYSTem:ERRor?
Clearing the Queue
Press: System, Show Errors,
Clear Error Queue
Power up
Send a *CLS command
Read last item in the queue
Error Message Format
The system-defined error numbers are chosen on an enumerated (“1 of N”) basis.
The error messages are listed in alphabetical order within each error message type
section.
In this chapter, an explanation is included with each error to further clarify its
meaning. The last error described in each class (for example, -400, -300, -200,
-100) is a “generic” error.
Error messages appear at the bottom of the display.
Chapter 3
85
Error Messages
Error Messages
Error Message Types
Events do not generate more than one type of error. For example, an event that
generates a query error will not generate a device-specific, execution, or command
error.
-499 to
-400: Query
Errors
-199 to
-100: Command
Errors
-399 to -300 and
201 to
799: Device-Speci
fic Errors
These errors indicate that the instrument output queue control has detected a
problem with the message exchange protocol described in IEEE 488.2, Chapter 6.
Errors in this class set the query error bit (bit 2) in the event status register (IEEE
488.2, section 11.5.1). These errors correspond to message exchange protocol
errors described in IEEE 488.2, 6.5. In this case:
•
Either an attempt is being made to read data from the output queue when no
output is either present or pending, or
•
data in the output queue has been lost.
These errors indicate that the instrument parser detected an IEEE 488.2 syntax
error. Errors in this class set the command error bit (bit 5) in the event status
register (IEEE 488.2, section 11.5.1). In this case:
•
Either an IEEE 488.2 syntax error has been detected by the parser
(a control-to-device message was received that is in violation of the IEEE 488.2
standard. Possible violations include a data element which violates device
listening formats or whose type is unacceptable to the device.), or
•
an unrecognized header was received. These include incorrect device-specific
headers and incorrect or non-implemented IEEE 488.2 common commands.
These errors indicate that a device operation did not properly complete, possibly
due to an abnormal hardware or firmware condition. These codes are also used for
self-test response errors. Errors in this class set the device-specific error bit (bit 3)
in the event status register (IEEE 488.2, section 11.5.1).
The <error_message> string for a positive error is not defined by SCPI.
86
Chapter 3
Error Messages
Error Messages
-299 to -200:
Execution Errors
These errors indicate that an error has been detected by the instrument’s execution
control block. The occurrence of any error in this class shall cause the execution
error bit (bit 4) in the event status register (IEEE 488.2, section 11.5.1) to be set.
One of the following events has occurred:
•
A <PROGRAM DATA> element following a header was evaluated by the
device as outside of its legal input range or is otherwise inconsistent with the
device’s capabilities.
•
A valid program message could not be properly executed due to some device
condition.
Execution errors shall be reported by the device after rounding and expression
evaluation operations have taken place. Rounding a numeric data element shall not
be reported as an execution error. Events that generate execution errors shall not
generate Command errors, device-specific errors, or Query errors.
0: No Error
0
No error
The queue is empty. Every error in the queue has been read or
the queue was purposely cleared by power-on or *CLS.
Chapter 3
87
Error Messages
Error Messages
-499 to -400: Query Errors
The instrument output queue control has detected a problem with the message
exchange protocol described in IEEE 488.2, Chapter 6. Errors in this class set the
query error bit (bit 2) in the event status register (IEEE 488.2, section 11.5.1).
These errors correspond to message exchange protocol errors described in IEEE
488.2, 6.5.
In this case, either an attempt is being made to read data from the output queue
when no output is either present or pending, or data in the output queue has been
lost.
-430
Query DEADLOCKED
Indicates that a SCPI output queue has filled, preventing further
SCPI command execution, and there is no more room left in the
corresponding SCPI input queue to accept a query to read from
the output queue. The system automatically discards output to
correct the deadlock.
-400
Query Error
This is a generic query error for devices that cannot detect more
specific errors. The code indicates only that a query error as
defined in IEEE 488.2, 11.5.1.1.7 and 6.3 has occurred.
-410
Query INTERRUPTED
Indicates that a condition causing an INTERRUPTED query
error occurred (see IEEE 488.2, 6.3.2.7). For example, a query
was followed by DAB or GET before a response was completely
sent.
-420
Query UNTERMINATED
Indicates that a condition causing an UNTERMINATED query
error occurred (see IEEE 488.2, 6.3.2.2). For example, the
device was addressed to talk and an incomplete program
message was received.
-440
Query UNTERMINATED after indefinite response
Indicates that a query was received in the same program
message after a query requesting an indefinite response was
executed (see IEEE 488.2, 6.3.7.5).
88
Chapter 3
Error Messages
Error Messages
-199 to -100: Command Errors
The instrument parser detected an IEEE 488.2 syntax error. Errors in this class set
the command error bit (bit 5) in the event status register (IEEE 488.2, section
11.5.1). In this case:
•
Either an IEEE 488.2 syntax error has been detected by the parser
(a control-to-device message was received that is in violation of the IEEE 488.2
standard. Possible violations include a data element which violates device
listening formats or whose type is unacceptable to the device.), or
•
an unrecognized header was received. These include incorrect device-specific
headers and incorrect or non-implemented IEEE 488.2 common commands.
-160
Block data error
This error, and also error -168, is generated when parsing a
block data element. This particular error message is used if the
device cannot detect a more specific error.
-168
Block data not allowed
A legal block data element was encountered, but not allowed by
the device at this point in the parsing.
-140
Character data error
This error, as well as errors -144 and -148, are generated when
parsing a character data element. This particular error message
is used if the device cannot detect a more specific error.
-148
Character data not allowed
A legal character data element was encountered where
prohibited by the device.
-144
Character data too long
The character data element contains more than twelve characters
(see IEEE 488.2, 7.7.1.4).
-100
Command error
This is a generic syntax error for devices that cannot detect more
specific errors. The code indicates only that a command error as
defined in IEEE 488.2, 11.5.1.1.4 has occurred.
Chapter 3
89
Error Messages
Error Messages
-110
Command header error
An error was detected in the header. This message is used when
the device cannot detect the more specific errors described for
errors -111 through -119.
-104
Data type error
The parser recognized a data element that is not allowed. For
example, numeric or string data was expected, but block data
was encountered.
-123
Exponent too large
The magnitude of an exponent was greater than 32000 (see
IEEE 488.2, 7.7.2.4.1).
-170
Expression error
This error, as well as error -178, is generated when parsing an
expression data element. This particular error message is used if
the device cannot detect a more specific error.
-178
Expression data not allowed
A legal expression data was encountered, but was not allowed
by the device at this point in parsing.
-105
GET not allowed
A Group Execute Trigger was received within a program
message (see IEEE 488.2, 7.7). Correct the GPIB controller
program so that the GET does not occur within a line of GPIB
program code.
-111
Header separator error
A character which is not a legal header separator was
encountered while parsing the header.
90
Chapter 3
Error Messages
Error Messages
-114
Header suffix out of range
The value of a header suffix attached to a program mnemonic
makes the header invalid.
-161
Invalid block data
A block data element was expected, but was invalid (see IEEE
488.2, 7.7.6.2). For example, an END message was received
before the end length was satisfied.
-101
Invalid character
A syntactic command contains a character which is invalid for
that type. For example, a header containing an ampersand,
SETUP&. This error might be used in place of error numbers
-114, -121, -141 and some others.
-141
Invalid character data
Either the character data element contains an invalid character
or the particular element received is not valid for the header.
-121
Invalid character in number
An invalid character for the data type being parsed was
encountered. For example, an alpha in a decimal numeric or a
“9” in octal data.
-171
Invalid expression
The expression data element was invalid (see IEEE 488.2,
7.7.7.2). For example, unmatched parentheses or an illegal
character.
-103
Invalid separator
The parser was expecting a separator and encountered an illegal
character. For example, the semicolon was omitted after a
program message unit.
-151
Invalid string data
A string data element was expected, but was invalid (see IEEE
488.2, 7.7.5.2). For example, an END message was received
before the terminal quote character.
Chapter 3
91
Error Messages
Error Messages
-131
Invalid suffix
The suffix does not follow the syntax described in IEEE 488.2,
7.7.3.2, or the suffix is inappropriate for this device.
-109
Missing parameter
Fewer parameters were received than required for the header.
For example, the *ESE common command requires one
parameter, so receiving *ESE is not allowed.
-120
Numeric data error
This error, as well as error -128, is generated when parsing a
data element which appears to be numeric, including
non-decimal numeric types. This particular error message is
used if the device cannot detect a more specific error.
-128
Numeric data not allowed
A legal numeric data element was received, but the device does
not accept one in this position for the header.
-108
Parameter not allowed
More parameters were received than expected for the header.
For example, the *ESE common command only accepts one
parameter, so receiving *ESE 0,1 is not allowed.
-112
Program mnemonic too long
The header contains more than twelve characters (see IEEE
488.2, 7.6.1.4.1).
-150
String data error
This error, as well as error -158, is generated when parsing a
string data element. This particular error message is used if the
device cannot detect a more specific error.
-158
String data not allowed
A string data element was encountered, but not allowed by the
device at this point in the parsing.
92
Chapter 3
Error Messages
Error Messages
-130
Suffix error
This error, as well as errors -134 and -138, are generated when
parsing a suffix. This particular error message is used if the
device cannot detect a more specific error.
-138
Suffix not allowed
A suffix was encountered after a numeric element which does
not allow suffixes.
-134
Suffix too long
The suffix contained more than twelve characters (see IEEE
488.2, 7.7.3.4).
-102
Syntax error
An unrecognized command or data type was encountered. For
example, a string was received when the device does not accept
strings.
-124
Too many digits
The mantissa of a decimal-numeric data element contained
more than 255 digits excluding leading zeros (see IEEE 488.2,
7.7.2.4.1).
-113
Undefined header
The header is syntactically correct, but it is undefined for this
specific device. For example, *XYZ is not defined for any
device.
Chapter 3
93
Error Messages
Error Messages
-399 to -300 and 201 to 799: Device-Specific Errors
Some device operations did not properly complete, possibly due to an abnormal
hardware or firmware condition. These codes are also used for self-test response
errors. Errors in this class set the device-specific error bit (bit 3) in the event status
register (IEEE 488.2, section 11.5.1).
The <error_message> string for a positive error is not defined by SCPI.
304
Alignment failed
The alignment failed because of one of the following reasons:
•
Gain less than 0
During alignment, the measured value of the IF section gain
was less than 0.
•
Microwave noise greater than signal
The alignment failed at the current microwave frequency
because the reading at the IF detector was greater when only
the noise floor of the instrument was present compared to
when the alignment noise source was on.
NOTE
This error can occur if the YTF alignment has not been performed at the current
operating temperature.
NOTE
This error applies only to the N8974A and N8975A.
•
Noise greater than signal
The reading at the IF detector was greater when only the
noise floor of the instrument was present compared to when
the alignment CW signal was present.
614
Bad or missing disk
The floppy is not inserted or the directory could not be read.
Insert a known good disk and try again.
219
Command not valid in this model
Indicates that the command sent from the remote interface does
not apply to this model number.
94
Chapter 3
Error Messages
Error Messages
615
Corrupted file
The file that you were trying to load is corrupt.
768
Failed to load ENR data
A problem occurred when attempting to load an ENR table.
771
Failed to load Freq list
A problem occurred when attempting to load a frequency list.
774
Failed to load Limit Line
A problem occurred when attempting to load a limit line.
779
Failed to load Loss data
A problem occurred when attempting to load loss data.
772
Failed to store Freq list
A problem occurred when attempting to save a frequency list.
769
Failed to store ENR data
A problem occurred when attempting to save an ENR table.
775
Failed to store Limit Line
A problem occurred when attempting to save a limit line.
780
Failed to save Loss data
A problem occurred when attempting to save loss data.
778
Failed to store Trace
A problem occurred when attempting to save a trace.
Chapter 3
95
Error Messages
Error Messages
610
File access is denied
The file is protected or hidden and cannot be accessed.
604
File already exists
Attempt to save to a file that already exists. Delete or rename the
old file and try again.
607
File name error
An invalid file name has been specified. Use filenames with a
maximum of 8 characters (letters and digits only) and use a 3
character extension. Note that lowercase and uppercase are
perceived as the same.
612
File does not exist
The analyzer could not find the specified file.
754
File does not exist
The state file you were trying to recall does not exist.
96
Chapter 3
Error Messages
Error Messages
500
Hardware config error
A hardware configuration error occurred due to one of the
following reasons:
•
Unknown product number
During start-up, an attempt to match the hardware found
against the NFA's product number could not be made
because the product number was unknown. This is a fatal
hardware configuration error.
•
HW ID x in slot y not required
A card with ID x was found in slot y but for this product
number is not required. This is a non-fatal hardware
configuration error.
•
HW ID x must be in slot y, not z
A card with ID x was found in slot z but was expected to be
found in slot y for this product number. This is a fatal
hardware configuration error.
•
HW ID x is missing
A card with ID x was expected for this product number but
was not found. This is a fatal hardware configuration error.
•
Measurement not possible
An attempt was made to perform a measurement but a
previous fatal hardware configuration error has occurred,
preventing measurements.
•
Option ’x’ not installed
Software option 'x' must be enabled for this product number,
but was not installed. The NFA will attempt to enable this
option, requiring a power cycle. This is a fatal hardware
configuration error. (until the option is reinstalled).
Chapter 3
97
Error Messages
Error Messages
300
IF autorange failed
The IF section could not be autoranged because of one of the
following:
•
RF att. is fixed
The RF front-end attenuation is fixed.
•
RF att. limit reached
The RF front-end attenuation limit is reached.
313
IF over range req. RF re-range: Meas.
restarted
During a continuous measurement, a IF section over range
condition occurred, requiring a change of RF front-end
attenuation. To do this the measurement needs to be restarted.
302
IF PLD error;Power detector read timed out
A read of the IF section power detector timed out.
603
Illegal MSDOS name given
An invalid file name has been specified. Use filenames with a
maximum of 8 characters (letters and digits only) and use a 3
character extension. Note that lowercase and uppercase are
perceived as the same.
770
Incorrect filename, allowable extension ENR
Attempt to save an ENR table to a file with an incorrect
extension.
763
Incorrect filename, allowable extensions are
GIF or WMF
Attempt to save a screen image to a file with an incorrect
extension.
776
Incorrect filename, allowable extensions LIM
Attempt to save limit line data to a file with an incorrect
extension.
98
Chapter 3
Error Messages
Error Messages
781
Incorrect filename, allowable extension LOS
An attempt was made to save loss data using an extension other
than LOS.
773
Incorrect filename, allowable extension LST
Attempt to save frequency list data to a file with an incorrect
extension.
777
Incorrect filename, allowable extension STA
Attempt to save the instrument state to a file with an incorrect
extension.
762
Incorrect filename, allowable extension CSV
Attempt to save a trace to a file with an incorrect extension.
782
Incorrect SNS data format
An attempt to read SNS data failed either because the device
attached was not an SNS or because the data was corrupt.
307
Input attenuation x dB not calibrated
Corrected measurements have been requested and the required
RF front-end attenuation setting of x dB has not been calibrated.
751
Instrument state may be corrupt, state has
been reset to initial values
An attempt was made to load a possibly corrupt state. The
instrument state is reset to the state prior to the attempt to load.
If the state load was for a user preset, then the instrument state is
reset to the factory state.
216
Invalid baud rate
Attempt to use invalid baud rate. Refer to the User’s Guide for
valid rates.
Chapter 3
99
Error Messages
Error Messages
308
Invalid frequency list for measurement mode
A frequency within the frequency list cannot be used to make a
measurement in the current mode.
306
Invalid input attenuation
An attempt was made to set an invalid RF front-end attenuation
limit for calibration.
701
Invalid printer response
In attempting to identify the printer an invalid response was
received. Check that you are using a supported printer. Be sure
you are using the proper cable and that it is securely fastened.
301
LO GPIB error
An LO GPIB error occurred because of one of the following:
•
Did not become system controller
An attempt to become system controller failed, possibly
because another controller is present on the LO GPIB bus.
•
Need to be system controller
To perform the required action, the NFA needs to be the
system controller on the LO GPIB bus and is not because a
prior attempt to become the system controller failed.
•
Controller collision
Another controller on the LO GPIB has attempted to use the
bus concurrently with the NFA.
•
Address bus timeout
Attempted to address bus and failed — check cabling
connections.
•
Write command timeout
Attempt to write command to device failed — check device
address is correct.
•
Read response timeout
Attempt to read response from device failed - check device
address is not the same as the LO GPIB address.
100
Chapter 3
Error Messages
Error Messages
606
Media is not writable
A save was attempted to a read-only device.
605
Media is protected
A save was attempted to a write-protected device.
315
Microwave input attenuation x dB not
calibrated
Corrected measurements have been requested and the required
microwave front-end attenuation setting of x dB has not been
calibrated.
305
Mode setup error
A mode setup error occurred because of one of the following:
•
System input frequency out of range
One or more system input frequencies are out of range. If
using a frequency list, check that all entries are valid for
current measurement mode.
•
External LO frequency out of range
One or more external LO frequencies are out of range.
Check that the LO frequency limits are set correctly and
check the entered measurement frequencies and
measurement mode.
•
Stop freq must be less than fixed LO freq
The current measurement mode requires that the stop
frequency must be less than the fixed LO frequency.
•
Start freq must be greater than start IF
freq
The current measurement mode requires that the start RF
(input to DUT) frequency must be greater than the start IF
(output from DUT) frequency.
•
LO - Stop freq must be >= min system input
freq
The current measurement mode requires that the difference
between the fixed LO frequency and the stop RF (input to
DUT) frequency must be more than the minimum system
input frequency.
Chapter 3
101
Error Messages
Error Messages
• Start freq must be greater than fixed LO freq
The current measurement mode requires that the start
frequency must be greater than the fixed LO frequency.
•
Stop IF freq must be less than fixed LO freq
The current measurement mode requires that the stop IF
(output from DUT) frequency must less than the fixed LO
frequency.
•
Start - LO freq must be >= min system input
freq
The current measurement mode requires that the start RF
(input to DUT) frequency must be more than the minimum
system input frequency away from the fixed LO frequency.
•
Stop freq must be less than stop RF freq
The current measurement mode requires that the stop IF
(output from DUT) frequency must be less than the stop RF
(input to DUT) frequency.
•
Start freq must be greater than start RF
freq
The current measurement mode requires that the start IF
(output from DUT) frequency must be greater than the start
RF (input to DUT) frequency.
•
Stop RF freq must be less than fixed LO freq
The current measurement mode requires that the stop RF
(input to DUT) frequency must be less than the fixed LO
frequency.
•
Start freq must be greater than fixed IF
freq
The current measurement mode requires that the start RF
(input to DUT) frequency must be greater than the fixed IF
frequency.
•
Start LO freq must be greater than fixed IF
freq
The current measurement mode requires that the start LO
frequency must be greater than the fixed IF frequency.
•
Stop freq must be less than fixed IF freq
The current measurement mode requires that the stop RF
(input to DUT) frequency must be less than the fixed IF
frequency.
102
Chapter 3
Error Messages
Error Messages
• Stop freq must be less than stop LO freq
The current measurement mode requires that the stop RF
(input to DUT) frequency must be less than the stop LO
frequency.
310
No entries in ENR table
A measurement was attempted or a SCPI query of an ENR table
was made and there were no entries in the relevant ENR table
(Common, Meas or Cal).
309
No entries in frequency list
A measurement was attempted with List frequency mode or a
SCPI query of the frequency list table was made and the
frequency list table is empty.
311
No entries in limit line table
A measurement was attempted using a limit line table, or a SCPI
query of an limit line table was made and there were no entries
in the relevant limit line table.
314
No entries in loss table
A measurement was attempted or a SCPI query of a loss table
was made and there were no entries in the relevant loss table
(either Before or After table).
700
No printer response
An attempt to identify the printer failed.
704
Printer interface error
An error occurred while trying to print. Make sure the printer is
turned on and properly connected.
705
Printer type is none
The current printer type is set to None, so no print operations are
possible. Change the type in the Print Setup menu and try again.
Chapter 3
103
Error Messages
Error Messages
-350
Queue Overflow
There is no room in the error queue and an error occurred but
was not recorded.
312
RF re-range required: Meas. restarted
During a continuous measurement, a change of RF front-end
attenuation was required. To do this the measurement needs
to be restarted.
217
RS-232 Interface Error
An error occurred on the serial interface due to one of the
following reasons:
•
Input data overrun
An error occurred on the serial interface.
•
Input data parity
An error occurred on the serial interface.
•
Input data framing
An error occurred on the serial interface.
•
Output data timeout
An error occurred on the serial interface
•
Command input timeout
An error occurred on the serial interface.
104
Chapter 3
Error Messages
Error Messages
-330
Self-Test Failed
A self-test error occurred due to one of the following reasons:
501
•
IF test [x][y] failure
•
RF test [x] failure
•
RF gain (x) out of range
•
IF gain out of range
•
RF cal x out of range amp[y]
•
RF amp[x] floor too high
•
Tuner EEPROM cal value out of range
•
IF filter offset x out of range
SNS read failure
An attempt to read from the SNS failed. This could be due to
SNS cable problems such as poor connection or disconnection
while reading.
502
SNS write failure
An attempt to write to the SNS failed. This could be due to SNS
cable problems such as poor connection or disconnection while
writing.
316
Thot must be greater than Tcold
A spot Thot temperature has been specified which is not greater
than Tcold temperature.
766
Unable to format drive
A problem occurred when attempting to format a drive.
765
Unable to load file
A problem occurred when attempting to load a file.
Chapter 3
105
Error Messages
Error Messages
759
Unable to load state file into instrument with
older firmware date
A saved state file from a newer firmware revision was attempted
to be loaded into an older instrument.
752
Unable to load state from file
An attempt to load a state from the File Manager or through
MMEM:LOAD:STAT failed. Preceding error messages may
indicate the cause of failure.
755
Unable to load state from register
An attempt to load a state from a register using the *RCL
command failed. Preceding error messages may indicate the
cause of failure.
757
Unable to load user state, factory preset was
done
An attempt to perform a User Preset failed, so the Factory Preset
values were used. Save a valid state into User Preset and try
again.
760
Unable to query state from the remote
A problem occurred while trying to query the instrument state as
part of a *LRN command.
764
Unable to save file
A failure occurred while saving a file; the file was not saved.
753
Unable to save state to file
An attempt to save a state from the File Manager or through
MMEM:STOR:STAT failed. Preceding error messages may
indicate the cause of failure.
106
Chapter 3
Error Messages
Error Messages
756
Unable to save state to register
An attempt to save a state to a register using the *SAV command
failed. Preceding error messages may indicate the cause of
failure.
758
Unable to save user state
An attempt to save the User Preset state failed.
761
Unable to set state from the remote
A problem occurred while trying to set the instrument state as
part of a SYST:SET command.
703
Unknown printer
In attempting to identify the printer, a valid response was
received but the printer is not known to the analyzer. Use the
Custom printer menu under Print Setup to configure the printer.
702
Unsupported printer
A printer which is recognized, but known to be unsupported was
identified. This printer cannot be used with the analyzer. For
example, a printer only supported by Microsoft Windows
generates this error.
Chapter 3
107
Error Messages
Error Messages
303
User cal invalidated
The existing user cal has been invalidated because of one of the
following reasons:
•
Meas mode changed
The measurement mode has been changed from that used for
user cal.
•
Freq outside cal range
The current measurement frequencies lie partially or wholly
outside the range of frequencies used for user cal.
•
Fixed IF changed
The fixed IF frequency has been changed from that used for
user cal.
•
Fixed LO changed
The fixed LO frequency has been changed from that used for
user cal.
•
Sideband changed
The sideband has been changed from that used for user cal.
660
YTF align error
The alignment failed because of one of the following reasons:
•
Peak / floor too small
During a YTF alignment the level of a peak above the noise
floor was too small. If this error occurs then the quality of
the YTF alignment is questionable.
•
Image / floor too small
During a YTF alignment the level of an image response
above the noise floor was too small. If this error occurs then
the quality of the YTF alignment is questionable.
108
Chapter 3
Error Messages
Error Messages
-299 to -200:
Execution Errors
-222
Data out of range
A parameter of a command or query was outside the defined
range for that command or query.
-224
Illegal parameter value
An unexpected value was entered. (for example, a value other
then the available options)
-225
Out of memory
The analyzer has insufficient memory to perform the requested
operation.
-221
Settings conflict
A legal program data element was parsed but could not be
executed due to the current device state.
-223
Too much data
A block, expression or string parameter of a command or query
contained more data than the analyzer could handle due to
memory constraints.
-213
Init ignored
Indicates that a request for a measurement initiation was ignored
as another measurement was in progress.
NOTE
The front panel Restart key does not generate this error, only the remote command
INIT:IMM.
-230
Data corrupt or stale
Possibly invalid data; new reading started but not completed
since last access.
Chapter 3
109
Error Messages
Error Messages
110
Chapter 3
4
Assembly Descriptions and Block
Diagrams
Chapter 4
111
Assembly Descriptions and Block Diagrams
What You Will Find in This Chapter
What You Will Find in This Chapter
This chapter provides information about the operation of the NFA that is useful
when first troubleshooting an NFA failure. Refer to the appropriate overall block
diagram at the end of this chapter when reading the assembly descriptions that
follow. The block diagrams show the assemblies in the NFA.
The NFA Series Noise Figure Analyzers are microprocessor-controlled swept
receivers with frequency ranges from 10.0 MHz to 1.5 GHz, 3.0 GHz, 6.7 GHz, or
26.5 GHz, depending on the model number. This chapter briefly describes the NFA
assemblies:
All of the assemblies listed below are connected to the serial digital interface
through the motherboard connection. The data and control information and the
power supplies, are distributed through these connections. Each of these
assemblies has its own individual EEPROM with stored serial numbers and
alignment data for the assembly.
•
“A8 RF Assembly” on page 4-113 which includes:
— “A8A1 RF Assembly” on page 4-114.
— “A8A1A1 Reference/Third Converter” on page 4-115.
— “A8A1A2 Front End/LO” on page 4-115.
It also controls the following assemblies:
— “A8A5 Input Attenuator” on page 4-116.
— “A8A2 Second Converter” on page 4-116.
•
“A7A3 Frequency Extension” on page 4-117.
It also controls the following assemblies:
— “A8A4 LO Amplifier/IF Switch (LOIS)” on page 4-116.
— “A8A6 YIG-Tuned Filter/Mixer (RYTHM)” on page 4-116.
•
“A7A5 IF Assembly” on page 4-118.
•
“A4 Processor Assembly” on page 4-119.
The assemblies listed below do not have individual EEPROMs.
•
“A8FL1 3.1 GHz Low-Pass Filter (LPF)” on page 4-116.
•
“A7 Motherboard and Card Cage Assemblies” on page 4-122.
•
“A1 Display/Front Panel” on page 4-123.
•
“A5 Power Supply Assembly” on page 4-121.
•
“Input Connector” on page 4-114.
•
“A2 RF Front End” on page 4-117.
•
“A3 Microwave Front End” on page 4-117.
112
Chapter 4
Assembly Descriptions and Block Diagrams
A8 RF Assembly
A8 RF Assembly
The A8 RF assembly performs the following major functions:
•
Converts the input noise energy to the 21.4 MHz IF.
•
Generates first, second and third local oscillator (LO) signals for up-conversion
and down-conversion.
•
Uses a fractional-N phase-locked loop for first LO stability.
•
Generates a 10.0 MHz reference signal.
•
Generates a 50.0 MHz reference signal to calibrate the A2 Front End.
•
Generates an internal 21.4 MHz IF alignment signal.
When tuned to frequencies ≤ 3.0 GHz, the RF section up-converts the signal to a
3.9214 GHz first IF, and then down-converts it to a 321.4 MHz second IF, and
finally to a 21.4 MHz third IF. When tuned to frequencies > 3.0 GHz, the RF
section down-converts the signal directly to the 321.4 MHz second IF and then to
the 21.4 MHz third IF.
The RF Section consists of four assembly board, and three microcircuits. Two of
the assembly boards (A8A1A1 and A8A1A2) comprise the A8A1 3.0 GHz RF
Assembly. Not all microcircuits and board assemblies are used in every model.
Refer to Table 4-1.
Chapter 4
113
Assembly Descriptions and Block Diagrams
A8 RF Assembly
Table 4-1
Assemblies Fitted into Models
Description
N8972A
and
N8973A
N8974A
and
N8975A
A8 RF Assembly
(includes A8A1A1 and A8A1A2)
X
X
A8A2 Second Converter
X
X
A8A4 LO Amplifier/IF Switch (LOIS)
A8A5 Input Attenuator
X
X
A8A6 YIG-Tuned Filter/Mixer (RYTHM)
X
X
A8FL1 3.1 GHz Low-Pass Filter (LPF)
X
X
A2 RF Front End Assembly
X
X
A3 Microwave Front End Assembly
X
A7A4 Frequency Extension
X
Input Connector
The input connector is mounted to the middle shield of the A8 RF Assembly. This
connector can be easily replaced without disassembling the RF section. Refer to
Chapter 6 for the removal procedure.
A8A1 RF Assembly
The A8A1 3.0 GHz RF Assembly is comprised of two boards, the A8A1A1
Reference/Third Converter and the A8A1A2 Front End/LO, in the same shield set.
The A8J10 input connector and the Amptd Ref Out connector (part of the
A8A1W4 50 MHz Ref Signal). Refer to the following descriptions for “A8A1A1
Reference/Third Converter” and “A8A1A2 Front End/LO.”
114
Chapter 4
Assembly Descriptions and Block Diagrams
A8 RF Assembly
A8A1A1 Reference/Third Converter
(Part of the A8A1 RF Assembly)
The standard frequency reference is a 10 MHz VCXO. Option 1D5 adds on
oven-controlled crystal oscillator (OCXO). The frequency reference is used to
phase-lock a 100 MHz VCXO. This 100 MHz signal is divided by two to yield the
50 MHz amplitude reference signal, and is tripled to provide the 300 MHz third
LO.
The 300 MHz third LO is then doubled to yield a 600 MHz signal which is the
reference for the first LO and will be used by the A8A2 Second Converter to
generate the 3.6 GHz second LO.
The second IF amplifiers provide approximately 24 dB of gain. There is also a 400
MHz low-pass filter and a 321.4 MHz bandpass filter before the third mixer. The
third mixer is an active mixer, which includes an IF amplifier. The third mixer
down-converts from 321.4 MHz to 21.4 MHz. A variable gain stage, controlled by
a DAC, follows the third mixer. The gain is set to provide −10 dBm output at
A8A1A1P5 when a −10 dBm signal is applied to the NFA input with 0 dB input
attenuation.
The third IF amplifier is followed by a switch to allow the 21.4 MHz alignment
signal from A8A1A2 to be routed to the A3 IF Assembly for performing automatic
IF alignments between sweeps. Either the output of the third amplifier or the 21.4
MHz alignment signal is routed to the A3 IF Assembly.
A8A1A1 also provides power and control signals for the A8A5 Input Attenuator
and the A8A2 Second Converter.
A8A1A2 Front End/LO
(Part of the A8A1 Assembly)
A limiter at the A8A1A2 input protects the first mixer from excessive RF signals.
A switch following the limiter allows the 50 MHz amplitude reference signal to be
switched-in to perform automatic RF alignments. The first mixer is an active mixer
with LO and IF amplifiers. A 700 MHz wide bandpass filter follows the first
mixer. The variable gain first IF amplifier corrects for conversion losses in the
front end.
The first LO uses a YIG-tuned oscillator in a fractional-N phase-locked loop
(PLL). The 600 MHz reference from A8A1A1 is divided by 128 or 129
dual-modulus prescaler and the resulting ~4.66 MHz signal is used as the reference
for the fractional-N PLL. The 21.4 MHz alignment signal is generated by dividing
the first LO signal by 64 and then limiting the divided signal. The first LO signal
drives a series of three directional couplers. The first directional coupler is used to
drive an ALC loop to level the first LO signal. The second directional coupler
provides feedback for the fractional-N PLL. The last directional coupler provides
an auxiliary first LO output for driving the A8A4 LO Amplifier/IF Switch (LOIS),
which then provides a first LO signal for the A8A6 YIG-Tuned Filter/Mixer
(RYTHM).
Chapter 4
115
Assembly Descriptions and Block Diagrams
A8 RF Assembly
A8A2 Second Converter
The A8A2 Second Converter down-converts the 3.9214 GHz first IF to a 321.4
MHz second IF. In high band, it passes the 321.4 MHz first IF from the A8A4 to
the A8A1A1 Reference/Third Converter. The converter generates a 3.6 GHz
second LO by multiplying a 600 MHz reference. Bandpass filters remove
unwanted harmonics of the 600 MHz driving signal. First IF and second LO
signals are filtered by cavity filters, which are not user-adjustable.
A8A4 LO Amplifier/IF Switch (LOIS)
The A8A4 Amplifier/IF Switch (LOIS) amplifies the auxiliary LO output from
A8A1A2 and levels the output, as necessary, to provide the optimum first LO
amplitudes to the A8A6 YIG-Tuned Filter/Mixer (RYTHM).
The IF switch routes the 321.4 MHz IF signal from A8A6 and amplifies it before
passing it along to the A8A2 Second Converter. The IF switch also allows for an
external 321.4 MHz IF input. A dc bias can be applied to the external IF input
signal and is not used in the NFA’s configuration of the A8A4 Amplifier/IF Switch
(LOIS)
The A8A4 LO Amplifier/IF Switch is controlled by the A7A4 Frequency
Extension assembly.
A8A5 Input Attenuator
The input attenuator provides 0 to 45 dB of attenuation in 5 dB steps. Pressing
Preset selects 0 dB attenuation.
A8A6 YIG-Tuned Filter/Mixer (RYTHM)
The A8A6 RYTHM (Routing YIG-Tuned Harmonic Mixer) is a microcircuit
which combines an RF switch, a tracking preselector, and a high-band mixer. The
PIN diode switch directs the RF input to the appropriate mixer in the A8A6 or the
A8A1 RF assembly.
The tracking preselector is a YIG-tuned filter. It functions as a tunable bandpass
filter for high-band signals (2.85 GHz to either 6.5, or 26.5 GHz). The
preselector’s tuned frequency is controlled by DACs on the A7A4 Frequency
Extension assembly.
The high-band mixer is ac coupled. It uses the first, second, and fourth harmonics
of the first LO to mix with the incoming signals to cover the frequency range.
A8FL1 3.1 GHz Low-Pass Filter (LPF)
The A8FL1 3.1 GHz LPF precedes the 3.0 GHz RF assembly to eliminate image
and out-of-band responses when in low-band. When in low-band, only signals
greater than 3.1 GHz can generate image and out-of-band responses. By filtering
out these signals, image and out-of-band responses are virtually eliminated.
116
Chapter 4
Assembly Descriptions and Block Diagrams
A8 RF Assembly
A2 RF Front End
The A2 Front End Assembly is designed to operate in the 10.0 MHz to 3.0 GHz
bandwidth region. It provides protection from transients, it use low noise
amplifiers and step attenuators to maintain linearity and provide the required
dynamic range. The power detector is used to control the attenuators.
A3 Microwave Front End
The A3 Microwave Front End Assembly is designed to operate in the 3.0 GHz to
26.5 GHz bandwidth region. It provides protection from transients, it use low
noise amplifiers and step attenuators to maintain linearity and provide the required
dynamic range. The power detector is used to control the attenuators. It contains a
3.0 GHz mechanical switch to control the broadband input noise energy applied
which crosses over the 3.0 GHz point.
A7A3 Frequency Extension
The A7A3 Frequency Extension provides power and control signals to the A8A4
LO Amplifier/IF Switch (LOIS) and the A8A6 YIG-Tuned Filter/Mixer
(RYTHM). A DAC on A7A4 is used to control the amplitude of LO outputs on the
A8A4. A variable-rate generator and sweep clock drive DACs, which control the
tuning of the preselector and the A8A6. Several drivers are provided to control the
PIN diode switches on A8A4 and A8A6. A DAC also provides bias to the
high-band mixer in A8A6.
The flatness correction data for high-band is stored on A7A3.
Chapter 4
117
Assembly Descriptions and Block Diagrams
A7A5 IF Assembly
A7A5 IF Assembly
The A7A5 IF assembly is a selective 4.0 MHz wide Power Meter centered around
a 21.4 MHz input signal.
The IF assembly provides the following main functions:
•
4.0 MHz Bandwidth Measurements
•
IF Gain Control
•
Routing for Narrow Bandwidth Measurements
IF Gain Control
The IF Gain Control is provided by a string of amplifiers, filters, and attenuators.
There are two strings, the first string processes the 21.4 MHz. This processed
output is downconverted to 6.25 MHz. The 6.25 MHz is processed by the second
string. The range of attenuation control is from 0 dB to 70 dB (in 1 dB steps).
4.0 MHz Bandwidth Measurements
The processed 6.25 MHz output is digitally converted and further processed in the
PLD to measure the true RMS power.
Narrow Bandwidth Measurements
The narrow bandwidth measurements (100 kHz to 2.0 MHz) are implemented
digitally using digital signal processing performed by the A7A4 assembly.
IF Detector Linearity
The IF Assembly contains an EEPROM which holds unique detector linearity
calibration data. This data sets the detector to 0dB over its 22dB range. Each IF
Assembly is characterized during the manufacturing process. The relevant
calibration data is then stored.
NOTE
The Calibration data is only unique to the IF card. Therefore, any characterized IF
Assembly can be fitted to any NFA. The IF Assembly is a modular replacement
therefore there is no re-programming required.
118
Chapter 4
Assembly Descriptions and Block Diagrams
A4 Processor Assembly
A4 Processor Assembly
The A4 processor assembly provides the following main functions:
•
Main CPU processing
•
Memory, including boot memory and firmware
•
Video filtering
•
Peak detection
•
Analog-to-digital conversion of the video output
•
Real-time clock
•
IF counters
•
Communicates with I/O assemblies
•
Front panel interface
•
LCD interface
NFA Battery Information
The NFA use a 3 V lithium battery to enable the internal memory to retain data.
The date that the battery was installed is displayed on a label on the rear panel of
the NFA. See Figure 4-1.
The minimum life expectancy of the battery is seven years at 25 °C. If you
experience problems with the battery, or the recommended time period for battery
replacement has elapsed see, “Contacting Agilent Technologies, Inc.” on
page 5-140.
If you wish to replace the battery yourself, refer to the “A4BT1 Battery” on
page -184 replacement procedure in Chapter 6. The battery is mounted onto the A4
Processor Assembly. If the battery fails or the battery connection is broken, the
real-time clock stops and all data stored in RAM is lost. This data needs to be
restored after the battery is replaced. The following are examples of the data types
that needs to be restored:
•
GPIB address or RS-232 baud rate.
•
Current correction factors (factory correction factors are stored on each
assembly)
•
Any saved states, for example, ENR tables, States, Traces, Limits,
Frequency Lists, and Loss Tables.
•
Any customized instrument settings, for example, display contrast.
After replacing the battery, write the date of battery replacement on the rear panel
label.
Chapter 4
119
Assembly Descriptions and Block Diagrams
A4 Processor Assembly
Figure 4-1
Rear Panel Battery Information Label
PROCESSOR
BATTERY LIFE
7 YEARS AT 25 C
!
INSTALLED
Interconnections to Other Assemblies
There are four connectors to the rear panel:
A4J7
VGA OUTPUT - drives an external VGA-compatible monitor
with a signal that has 31.5 kHz horizontal, 60 Hz vertical
synchronizing rate, non-interlaced.
A4J1
(service connector for factory use only)
A4J8
GATE TRIG/EXT TRIG IN (TTL) - not currently supported.
A4J9
GATE/HI SWP OUT (TTL) - not currently supported.
The A4J6 front panel interface connector contains the signals and voltages for all
front panel circuitry:
•
Power supplies.
•
Rotary pulse generator (RPG) interface.
•
Front panel keyboard interface.
•
AT keyboard interface. An AT-style PC keyboard can be plugged into the front
panel. This feature is currently not implemented.
•
LCD digital interface. The display controller for the processor assembly can
drive an LCD (internal) and a VGA (external) CRT simultaneously.
•
Front panel serial interface. This is used to communicate with the front panel of
the instrument.
•
Probe power (unfiltered supply). The −15 V supply is converted to −12.6 V on
the front panel interface board for the probe power connector.
A4A1 Flash SIMM
The A4A1 Flash SIMM provides memory for firmware storage.
A4A2 DRAM SIMM
The A4A2 DRAM SIMM provides additional memory for storing states, for
example, ENR tables, States, Traces, Limits, Frequency Lists, and Loss Tables.
120
Chapter 4
Assembly Descriptions and Block Diagrams
A5 Power Supply Assembly
A5 Power Supply Assembly
The A5 Power Supply Assembly can be powered by a 90 to 140 volt or 200 to 264
volt ac supply. It supplies the instrument with all of the supply voltages listed
below. The line module, line fuse, and the dc power connector and dc fuse are all
part of the power supply assembly. Refer to the parts list in Chapter 5 for the fuse
types.
NOTE
The A5 Power Supply Assembly can be powered by an external 12 to 22 Vdc
supply, This feature is not available when used in an NFA.
If the instrument loses power for more than 30 seconds, the controller may not
retain the power-on state (On or Off) selected by the operator. When power is
restored, the instrument will normally be Off. To set the instrument to
automatically turn On when power is applied, set the switch at the rear of the
instrument. This feature is especially useful under the following conditions:
•
If the instrument is in a rack with other instruments, the entire rack can be
turned on with a single switch.
•
If the instrument is operating unattended, you may want to have measurements
continue after power is restored.
The fan is mounted directly to the power supply assembly. The fan speed varies
with internal instrument temperature; as the internal temperature increases, the fan
speed also increases.
NOTE
Because of safety concerns, the power supply is not repairable.
Interconnections to Other Assemblies
The following power supply connections can be made to other assemblies:
•
+5 V, +15 V, +28 V, −5 V, and −15 V supplies to the power supply bus
•
Voltage for the fan control
•
Connector at the rear panel for a dc supply input.
Chapter 4
121
Assembly Descriptions and Block Diagrams
A7 Motherboard and Card Cage Assemblies
A7 Motherboard and Card Cage Assemblies
The A7 motherboard provides the power supply and digital bus interconnections
between assemblies in the NFA.
A7A1 GPIB Assembly
This A7A1 assembly allows you to control the NFA from a computer that has a
General Purpose Interface Bus (GPIB). The GPIB assembly contains an IEEE-488
bus connector. The assembly also includes a 25-pin parallel interface connector for
connection with an IEEE 1284 cable to PCL3 or PCL5 compatible printers.
A7A2 SIB Assembly
The A7A2 SIB Assembly controls the following four functions:
1. The RS-232 interface.
This allows you to control your NFA from a computer using that type of
interface. It has an RS-232 9-pin connector (Agilent 5182-4794).
2. The LO GPIB interface.
This allows the dedicated control of an external LO by the NFA.
3. The +28V Noise Source Supply (pulsed).
This is supplied from this board to the BNC connector on the front panel. The
cable supplying the +28V to the noise source is two sections, hence there is a
connecting section in the card cage frame.
4. The SNS Connector interface.
This supplies the interface and associated hardware to control the SNS.
A7A4 DSP Assembly
The A7A4 Digital Sample Processing (DSP) Assembly is used only on models,
N8973A, N8974A, and N8975A when making the narrow bandwidth
measurements of: 2.0 MHz, 1.0 MHz, 400.0 KHz, 200.0 KHz, and 100.0 KHz.
NOTE
The 4.0 MHz bandwidth is measured with the A7A5 IF Assembly.
122
Chapter 4
Assembly Descriptions and Block Diagrams
Miscellaneous
Miscellaneous
A1 Display/Front Panel
Display
The display is an LCD color flat screen with 640 × 480 VGA resolution. A
connector for an external VGA display is available at the rear panel.
A1A1 Front Panel Interface Board
The A1A1 front panel interface board provides the interface between the display
generation circuitry on the processor assembly and the display. It also interfaces
the front panel keyboard to the processor assembly. Any display-specific voltages
(other than 5 V digital) are created on this board. The front panel interface board
also includes the following:
•
Main RPG
•
Volume RPG
•
Plug for external AT style PC keyboard
•
Probe power (−12.6 Vdc, +15 Vdc, and ground)
•
Circuits to digitally adjust the display
A1A4 Backlight Supply
The A1A4 backlight supply provides the high voltage to supply the two backlights
in the LCD display.
A6 Floppy Drive Assembly
The A6 Floppy (A:) drive allows you to copy data to and from the NFA’s internal
(C:) drive.
Chapter 4
123
Assembly Descriptions and Block Diagrams
Block Diagrams
Block Diagrams
Graphic Symbols Used On Block Diagrams
Bus Line
Indicates a plug-in
connection (F) to (M)
Connection symbol
indicating plug (movable)
1
Band Pass Filter
Op Amplifier
High Pass Filter
Summer
F
¦
Low Pass Filter
Phase
Frequency Detector
Connection symbol
indicating jack (movable)
Mixer
Heavy line indicates
path and direction
of main signal
Oscillator or
Generator
Color code for cable
Capacitor
Variable Gain
Amplifier
Resistor
Band Reject Filter
Common
Return
TP?
?
Variable Resistor
Numbered
Test Point.
Measurement
aid provided.
Lettered
Test Point. No
Measurement
aid provided.
Amplifier Buffer
Switch Open
Inverter Buffer
Slide, Toggle, or
Rocker, Switch
Diode
Grounded
Coaxial Sheilding
Limiter
Variable
Integrator
ADC
Analog Digital
Convertor
DAC
Digital Analog
Convertor
Directional
Coupler
formt123
124
Chapter 4
Assembly Descriptions and Block Diagrams
Block Diagrams
Figure 4-2
N8972A and N8973A Block Diagram
Chapter 4
125
Assembly Descriptions and Block Diagrams
Block Diagrams
Figure 4-3
N8974A and N8975A Block Diagram
126
Chapter 4
Assembly Descriptions and Block Diagrams
Block Diagrams
Figure 4-4
A7A5 IF Assembly Block Diagram
Chapter 4
127
Assembly Descriptions and Block Diagrams
Block Diagrams
Figure 4-5
RF Models Cable References and Connectors
128
Chapter 4
Assembly Descriptions and Block Diagrams
Block Diagrams
Figure 4-6
Microwave Models Cable References and Connectors
Chapter 4
129
Assembly Descriptions and Block Diagrams
Block Diagrams
130
Chapter 4
5
Parts List
Chapter 5
131
Parts List
What You Will Find in This Chapter
What You Will Find in This Chapter
This chapter contains information for identifying and ordering replacement
assemblies.
Major assembly location information is provided in Chapter 6.
Component level information containing material lists, schematics, and component
location diagrams, is available separately.
The following tables are included in this chapter:
•
Table 5-1 lists reference designator descriptions.
•
Table 5-2 lists value multipliers.
•
Table 5-3 lists replacement parts.
132
Chapter 5
Parts List
How to Order Parts
How to Order Parts
To order an assembly or mechanical part listed in this chapter, quote the Agilent
Technologies, Inc. part number and indicate the quantity required.
To order a part that is not listed, include the following information with the order:
o Analyzer model number.
o Analyzer serial number.
o Description of where the part is located, what it looks like, and its function (if
known).
o Quantity needed
Parts can be ordered by addressing the order to the nearest Agilent Technologies,
Inc. office. Customers within the USA can also use either the direct mail-order
system, or the direct phone-order system described below. The direct phone-order
system has a toll-free phone number available.
Direct Mail-Order System
Within the USA, Agilent Technologies, Inc. can supply parts through a direct
mail-order system. Advantages of using the system are as follows:
o Direct ordering and shipment from Agilent Technologies, Inc.
o No maximum or minimum on any mail order. (There is a minimum order
amount for parts ordered through a local Agilent Technologies, Inc. office
when the orders require billing and invoicing.)
o Prepaid transportation. (There is a small handling charge for each order.)
o No invoices.
To provide these advantages, a check or money order must accompany each order.
Mail-order forms and specific ordering information are available through your
local Agilent Technologies, Inc. office.
Chapter 5
133
Parts List
How to Order Parts
Direct Phone-Order System
Within the USA, a phone order system is available for regular and hotline
replacement parts service. A toll-free phone number is available, and Mastercard
and Visa are accepted. Outside the USA, get in touch with your local sales and
service office. For a list of sales and service office locations refer to Table 5-4 on
page 140.
Regular and Hotline Orders
The toll-free phone number (800) 227-8164 is available Monday through Friday, 6
a.m. to 5 p.m. (Pacific time). Regular orders have a four-day delivery time. For
after hours, use the fax number (800) 329-4470.
Table 5-1
Reference Designations
REFERENCE DESIGNATIONS
A
Assembly
E
Miscellaneous Electrical Part
P
Electrical Connector
(Movable Portion),
Plug
B
Fan, Motor
F
Fuse
BT
Battery
FL
Filter
R
Resistor
C
Capacitor
J
Electrical Connector
S
Switch
DS
Annunciator, Lamp,
(Stationary Portion),
W
Cable, Wire,
Light Emitting
Jack
Jumper
Diode (LED),
K
Relay
Signaling Device
L
Coil, Inductor
(Visible)
MP
Miscellaneous Mechanical Part
Table 5-2
Multipliers
MULTIPLIERS
Abbreviation
Prefix
Multiple
Abbreviation
Prefix
Multiple
T
tera
1012
m
milli
10−3
G
giga
109
µ
micro
10−6
M
mega
106
n
nano
10−9
k
kilo
103
p
pico
10−12
da
deka
10
f
femto
10−15
d
deci
10−1
a
atto
10−18
c
centi
10−2
134
Chapter 5
Parts List
Replaceable Parts
Replaceable Parts
A1
Front Panel Assembly Kita
Agilent Part
Number
N8972-61004
X
X
N8974-61005
A1A1
A1A1A1
Front Panel Interface Board Assembly
Rotary Pulse Generator
A1A1MP1
Backlight Inverter EMI Shield
A1A1W1
Backlight Inverter Cable
A1A2
LCD Assembly Kit
N8975A
Description
N8974A
Reference
Designator
N8973A
Assembly Level Replaceable Parts
N8972A
Table 5-3
X
X
N8972-60005
X
X
X
X
1990-1865
X
X
X
X
E4401-00046
X
X
X
X
8120-8482
X
X
X
X
E4401-60180
X
X
X
X
A1A2DS1
Display Backlight, Upper
2090-0577
X
X
X
X
A1A2DS2
Display Backlight, Lower
2090-0577
X
X
X
X
A1A2MP1
LCD Bracket
E4401-00034
X
X
X
X
A1A3MP9
Lens/Keypad Assembly
N8972-61017
X
X
X
X
Shock Spreader Assembly
E4403-60032
X
X
X
X
Subpanel Kit
E4401-60104
X
X
X
X
A1A5
A1MP3
N8974-61004
A1MP4
Flex Circuit, Main
E4401-60070
X
X
X
X
A1MP5
Main Keypad
N8972-40002
X
X
X
X
A1MP7
RPG Knob
0370-3229
X
X
X
X
A1MP10
Front Panel Connector Cover
E4401-40006
X
X
X
X
A1MP11
Media Door Assembly Kit
N8972-61012
X
X
X
X
A1MP12
Front Panel Cover
E4401-60193
X
X
X
X
A1MP14
Probe and Keyboard Cover
E4401-40006
X
X
X
X
A1MP16
Model ID Name Plate, 1.5 GHz
(N8972A)
N8972-80004
X
Model ID Name Plate, 3.0 GHz
(N8973A)
N8973-80001
Model ID Name Plate, 6.7 GHz
(N8974A)
N8974-80003
Model ID Name Plate, 26.5 GHz
(N8975A)
N8975-80002
Chapter 5
X
X
X
135
Parts List
Replaceable Parts
Agilent Part
Number
N8975A
Description
N8974A
Reference
Designator
N8973A
Assembly Level Replaceable Parts
N8972A
Table 5-3
A1MP17
Front Frame EMI Kit
N8972-61011
X
X
X
X
A1MP18
RF Input Connector Gasket
E4403-20046
X
X
X
X
A1MP20
28V Supply Connector Gasket
E4401-20089
X
X
X
X
Microwave Front End Assembly
N8974-60001
X
X
Microwave Front End Exchange
Assembly
N8974-69001
X
X
A3
Front End Board Assembly
N8972-60001
X
X
X
X
A4
Processor Assembly, Basic
N8974-60009
X
X
X
X
A4A1
4 MB Flash SIMM
E4401-60105
X
X
X
X
A4A2
16 MB DRAM SIMM
1818-6430
X
X
X
X
A4BT1
3 V Lithium Battery
1420-0556
X
X
X
X
E4401-60186
X
X
X
X
A2
A5
Power Supply Assembly
A5B1
Fan
3160-0866
X
X
X
X
A5F1
Fuse (dc) 30 A, 32 V
2110-0809
X
X
X
X
A5F2
Fuse (Line) 5 A, 250 V
2110-0709
X
X
X
X
Plastic Rivet
0361-1814
X
X
X
X
A5MP1−4
A6
Floppy Disc Board Assembly
N8972-60004
X
X
X
X
A7
Motherboard
E4401-60107
X
X
X
X
A7A1
GPIB Board Assembly
E4401-60013
X
X
X
X
A7A2
SIB Board Assembly (LO GPIB)
N8972-60003
X
X
X
X
A7A3
Frequency Extension Assembly
E4404-63001
X
X
A7A4
DSP Board Assembly
N8973-60001
X
X
X
A7A5
IF Board Assembly
N8972-60002
X
X
X
X
IF Board Exchange Assembly
N8972-69001
X
X
X
X
IF Board Fan
E5515-61122
X
X
X
X
A7A5MP1
136
Chapter 5
Parts List
Replaceable Parts
A8
N8975A
N8974A
Reference
Designator
N8973A
Assembly Level Replaceable Parts
N8972A
Table 5-3
Description
Agilent Part
Number
N8972/3A RF Assembly
E4403-60037
X
X
N8972/3A RF Exchange Assembly
E4403-69037
X
X
N8972/3A - 1D5 RF Assembly
Precision Frequency Reference
E4403-60038
X
X
N8972/3A - 1D5 RF Exchange
Assembly Precision Frequency Ref.
E4403-69038
X
X
N8974/5A RF Assembly
N8974-60012
X
X
N8974/5A RF Exchange Assembly
N8974-69012
X
X
N8974/5A - 1D5 RF Assembly
Precision Frequency Reference
N8972-60013
X
X
N8974/5A - 1D5 RF Exchange
Assembly Precision Frequency Ref.
N8972-69013
X
X
A8A2
Second Converter
5086-7958
X
X
X
X
A8A3
DC Block Input Blanking Plate
N8972-61008
X
X
X
X
A8A4
LO Amplifier/IF Switch (LOIS)
E4404-60026
X
X
A8A5
Input Attenuator
33321-60060
X
X
A8A6
26.5 GHz YIG-Tuned Harmonic
Mixer (RYTHM)
5087-7031
X
X
26.5 GHz YIG-Tuned Harmonic
Mixer (RYTHM) Exchange
5087-6031
X
X
A8FL1
3.1 GHz Low Pass Filter (LPF)
0955-1134
X
X
A8MP1
Micro Bracket
E4404-00001
X
X
A8MP2
Sub Bracket
E4404-00003
X
X
A8MP3
Filter Clamp
5022-3619
X
X
A8MP4
Attenuator Bracket
E4403-00001
X
X
X
X
A8MP5
Filter Bracket
N8972-00003
X
X
X
X
Rear Frame Assembly
E4401-20021
X
X
X
X
Type-N Connector Gasket, RF Input
E4403-20046
X
X
MP1
Chassis Cover, Inner Shield
N8972-61002
X
X
X
X
MP4
Dress Cover
N8974-00007
X
X
X
X
MP5
Handle Assembly
E4401-40001
X
X
X
X
MP6
Chassis
E4401-00045
X
X
Microwave Chassis
N8974-61003
X
X
A1A4
A8MP24
Chapter 5
X
X
X
X
137
Parts List
Replaceable Parts
MP7
Vibration Support
W1
Cable Assembly, Processor to Front
Panel Interface (Ribbon Cable)
W3
Agilent Part
Number
N8975A
Description
N8974A
Reference
Designator
N8973A
Assembly Level Replaceable Parts
N8972A
Table 5-3
E4401-40026
X
X
X
X
8120-6919
X
X
X
X
Cable Assembly, Front Panel Interface
to Display (Ribbon Cable)
E4401-60070
X
X
X
X
W4
Cable Assembly, RF Power and
Control (Ribbon Cable)
E4403-60018
X
X
X
X
W5
Cable Assembly, Attenuator and 2nd
Converter Power and Control
(Ribbon Cable)
E4403-60019
X
X
Cable Assembly, Attenuator and 2nd
Converter Power and Control
(Ribbon Cable)
N8974-60014
X
X
Cable Assembly, I/P to A8FL1J1
(Semi-rigid Coaxial)
N8972-21001
Cable Assembly, I/P to A3J1
(Semi-rigid Coaxial)
N8974-21007
X
X
W7
Cable Assembly, A3J2 to A8FL1J1
(Semi-rigid Coaxial)
N8974-21010
X
X
W8
Cable Assembly, A8A1A2J2 to A2J2
(Semi-rigid Coaxial)
N8972-21003
Cable Assembly, A8A1A2J2 to A2J2
(Semi-rigid Coaxial)
N8974-21008
X
X
W9
Cable Assembly, A8A1A2J3 to
A8A2J1 3.9107 GHz IF
(Semi-rigid Coaxial)
E4403-20029
X
X
X
X
W10
Cable Assembly, 600 MHz 2nd LO
Drive A8A1A1P1 to A8A2J4
(Flexible Coaxial)
8120-8674
X
X
X
X
W11
Cable Assembly, 2nd Converter
321.4 MHz IF Output A8A2J2 to
A8A1A1P2 (Flexible Coaxial)
8120-8674
X
X
X
X
W12
Cable Assembly, A8FL1J2 to A8A5J1
(Semi-rigid Coaxial)
N8972-21002
X
X
Cable Assembly, A8FL1J2 to A8A5J1
(Semi-rigid Coaxial)
N8974-21009
X
X
W6
138
X
X
X
X
Chapter 5
Parts List
Replaceable Parts
W13
Agilent Part
Number
Cable Assembly, A8A5J2 to A2J1
(Semi-rigid Coaxial)
N8972-21006
Cable Assembly, A8A5J2 to A2J1
(Semi-rigid Coaxial)
N8974-21006
X
X
W14
Cable Assembly, A3J5 to A8A6J3
(Semi-rigid Coaxial)
N8974-21005
X
X
W15
Cable Assembly, A8A1A2J4 to A3J3
(Flexible Coaxial)
X
X
W16
Cable Assembly, RYTHM/LOIS
Power and Control
N8974-60011
X
X
W20
Cable Assembly, A8A6J1 to A8A4J5
RYTHM 321.4 MHz IF Output
(Flexible Coaxial)
8120-8674
X
X
W21
Cable Assembly, A8A4J7 to A8A2J3
(Flexible Coaxial)
8120-5141
X
X
W23
Cable Assembly, A8A1A2J5 to
A8A4J1 Auxiliary LO Output
(Semi-rigid Coaxial)
E4404-20008
X
X
W24
Cable Assembly, A8A4J2 to A8A6J4
RYTHM LO (Semi-rigid Coaxial)
E4404-20005
X
X
W25b
Cable Assembly, A7A2J102 to +28V
port
8120-5042
X
X
W26b
Cable Assembly, A7A2J102 to +28V
port
8120-5042
X
X
W28
Cable Assembly, A7A2J102 to front
panel +28V port (Flexible Coaxial)
N8974-60015
Xb
Xb
X
X
W31
Cable Assembly, 21.4 MHz IF Output
A8A1A1P5 to A7A5J100 (Flexible
Coaxial)
8120-5024
X
X
X
X
W32
Cable Assembly, A7A4P4 to
A7A5J102 (Flexible Coaxial)
8120-8790
X
X
X
W33
Cable Assembly, A7A4S1 to
A7A5J103 (Ribbon Cable)
8120-6986
X
X
X
8120-5105
X
N8975A
Description
N8974A
Reference
Designator
N8973A
Assembly Level Replaceable Parts
N8972A
Table 5-3
X
X
X
a. Ensure you order the appropriate Model ID Name Plate (A1MP16)
b. On earlier versions of the N8972A and N8973A the W28 cable assembly used two parts, W25 and W26,
to provide the connection between A7A2J102 and the +28V port.
Chapter 5
139
Parts List
Contacting Agilent Technologies, Inc.
Contacting Agilent Technologies, Inc.
Use the information in this section to obtain Agilent Technologies, Inc. sales and
service offices information. Sales and service offices are located around the world
to provide complete support for your analyzer. To obtain servicing information or
to order replacement parts, get in touch with the nearest Agilent Technologies, Inc.
Sales and Service office listed in Table 5-4. In any correspondence or telephone
conversations, refer to the analyzer by its model number and full serial number.
With this information, the Agilent representative can quickly determine whether
your unit is still within its warranty period.
If you have a problem with your Agilent N2717A Performance Verification
Software, get in touch with Agilent Technologies, Inc. for assistance. For software
technical support, get in touch with the Agilent Technologies, Inc. Test and
Measurement Call Center at 1-800-452-4844.
By internet, phone, or fax, get assistance with all your test and measurement needs.
Table 5-4 Contacting Agilent
On-line assistance: www.agilent.com/find/assist
United States
(tel) 1 800 452 4844
Japan
(tel) (+81) 426 56 7832
(fax) (+81) 426 56 7840
New Zealand
(tel) 0 800 738 378
(fax) (+64) 4 495 8950
Europe
(tel) (+31) 20 547 2323
(fax) (+31) 20 547 2390
Canada
(tel) 1 877 894 4414
(fax) (905) 282 6495
Latin America
(tel) (305) 269 7500
(fax) (305) 269 7599
Australia
(tel) 1 800 629 485
(fax) (+61) 3 9210 5947
Asia Call Center Numbers
Country
Phone Number
Fax Number
Singapore
1-800-375-8100
(65) 836-0252
Malaysia
1-800-828-848
1-800-801664
Philippines
(632) 8426802
1-800-16510170 (PLDT Subscriber
Only)
(632) 8426809
1-800-16510288 (PLDT
Subscriber Only)
Thailand
(088) 226-008 (outside Bangkok)
(662) 661-3999 (within Bangkok)
(66) 1-661-3714
Hong Kong
800-930-871
(852) 2506 9233
Taiwan
0800-047-866
(886) 2 25456723
People’s Republic of
China
800-810-0189 (preferred)
10800-650-0021
10800-650-0121
India
1-600-11-2929
000-800-650-1101
140
Chapter 5
Parts List
Contacting Agilent Technologies, Inc.
Instrument Serial Numbers
Agilent Technologies, Inc. makes frequent improvements to its products to
enhance performance, usability, or reliability. Agilent Technologies, Inc. service
personnel have access to complete records of design changes to each type of
instrument, based on the instrument’s serial number and option designation.
Whenever you contact Agilent Technologies, Inc. about your analyzer, have the
complete serial number available. This will ensure that you obtain accurate service
information.
A serial number label is attached to the rear of the analyzer. This label has two
instrument identification entries: the first provides the instrument’s serial number,
and the second provides the identification number for each option built into the
instrument.
The serial number has two parts: the prefix (two letters and the first four numbers),
and the suffix (the last four numbers). Refer to Figure 5-1.
Figure 5-1
Example Serial Number
Serial Number
Prefix
Suffix
The two letters identify the country in which the unit was manufactured. The four
numbers of the prefix are a code identifying the date of the last major design
change incorporated in your analyzer. The four digit suffix is a sequential number
and, coupled with the prefix, provides a unique identification for each unit
produced. Whenever you list the serial number or refer to it in obtaining
information about your analyzer, be sure to use the complete number, including the
full prefix and the suffix.
Chapter 5
141
Parts List
How to Return Your Analyzer for Service
How to Return Your Analyzer for Service
Service Tag
If you are returning your analyzer to Agilent Technologies, Inc. for servicing, fill
in and attach a blue service tag. Several service tags are supplied at the rear of this
chapter. Please be as specific as possible about the nature of the problem. If you
have recorded any error messages that appeared on the display, or have completed
a Performance Test Record, or have any other specific data on the performance of
your analyzer, please send a copy of this information with your analyzer.
Original Packaging
Before shipping, pack the unit in the original factory packaging materials if they
are available. If the original materials were not retained, see “Other Packaging” on
page 5-144.
NOTE
Ensure that the instrument handle is in the rear-facing position in order to reduce
the possibility of damage during shipping. Refer to the following illustration.
NOTE
Install the transportation disk into the floppy drive to reduce the possibility of
damage during shipping. If the original transportation disk is not available, a blank
floppy may be substituted.
142
Chapter 5
Parts List
How to Return Your Analyzer for Service
Chapter 5
143
Parts List
How to Return Your Analyzer for Service
Other Packaging
CAUTION
Analyzer damage can result from using packaging materials other than those
specified. Never use styrene pellets in any shape as packaging materials. They do
not adequately cushion the equipment or prevent it from shifting in the carton.
They cause equipment damage by generating static electricity and by lodging in
the analyzer louvers, blocking airflow.
You can repackage the instrument with commercially available materials, as
follows:
1. Attach a completed service tag to the instrument.
2. Install the transportation disk or a blank floppy disk into the disk drive.
3. If you have a front-panel cover, install it on the instrument. If you do not have a
front panel cover, make sure the instrument handle is in the forward-facing
position to protect the control panel.
4. Wrap the instrument in antistatic plastic to reduce the possibility of damage
caused by electrostatic discharge.
5. Use a strong shipping container. A double-walled, corrugated cardboard carton
with 159 kg (350 lb) bursting strength is adequate. The carton must be both
large enough and strong enough to accommodate the analyzer. Allow at least 3
to 4 inches on all sides of the analyzer for packing material.
6. Surround the equipment with three to four inches of packing material to
prevent the equipment from moving in the carton. If packing foam is not
available, the best alternative is S.D.-240 Air Cap™ from Sealed Air
Corporation (Hayward, California, 94545). Air Cap looks like a plastic sheet
filled with 1-1/4 inch air bubbles. Use the pink-colored Air Cap to reduce static
electricity. Wrapping the equipment several times in this material should both
protect the equipment and prevent it from moving in the carton.
7. Seal the shipping container securely with strong nylon adhesive tape.
8. Mark the shipping container “FRAGILE, HANDLE WITH CARE” to assure
careful handling.
9. Retain copies of all shipping papers
144
Chapter 5
6
Replacing Assemblies
Chapter 6
145
Replacing Assemblies
What You Will Find in This Chapter
What You Will Find in This Chapter
The procedures in this chapter describe the location, removal and replacement of
assemblies in the noise figure analyzer. Refer to Chapter 5, “Parts List,” for part
numbers and ordering information. Refer to Chapter 4, “Assembly Descriptions
and Block Diagrams,” for assembly descriptions.
Numbers in parentheses, for example (1), indicate numerical callouts on the
figures.
146
Chapter 6
Replacing Assemblies
Before You Start
Before You Start
Before starting to disassemble the instrument:
•
Check that you are familiar with the safety symbols marked on the instrument,
and read the general safety considerations and the safety note definitions given
in the front of this guide.
•
The noise figure analyzer contains static sensitive components. Read the
section entitled “ESD Information” in Chapter 1.
Service tools you will need
Figure 6-1
TORX Tool
Table 6-1
Description
NOTE
Agilent Part Number
TORX Hand Driver - Size T8
8710-1614
TORX Hand Driver - Size T10
8710-1623
TORX Hand Driver - Size T15
8710-1622
Refer to Table 2-2 for the correct torque value to be applied to the cable connector.
After a noise figure analyzer repair
If one or more noise figure analyzer assemblies have been replaced, perform the
calibration and performance verification tests. Refer to Chapter 7, “Post-Repair
Procedures,” for further information on the calibration and performance
verification tests.
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147
Replacing Assemblies
Removal and Replacement Procedures in This Chapter
Removal and Replacement Procedures in This Chapter
This chapter describes the removal and replacement procedures for the following
Agilent NFA series noise figure analyzer assemblies:
“Instrument Outer Case” on page 149
“Chassis Cover” on page 153
“A1 Front Frame Assembly” on page 155
“A1MP16 Nameplate” on page 159
“Connector Label” on page 160
“Front Frame Subassemblies” on page 164, which includes:
“A1A2 Display” on page 164
“A1A1 Front Panel Interface Board” on page 167
“Front Panel RPG” on page 169
“Keypad/Flex Circuit” on page 170
“A1A3MP9 Lens/Keypad Assembly” on page 171
“A1A2DS1/A1A2DS2 Display Backlight” on page 172
“A1MP11 Media Door/Bezel” on page 173
“A3 Microwave Front End Assembly” on page 177
“A2 RF Front End” on page 179
“A4 Processor Assembly” on page 181
“A4A1 and A4A2 Flash and DRAM SIMM” on page 183
“A4BT1 Battery” on page 184
“A5 Power Supply” on page 185
“A5B1 Fan” on page 187
“A6 Floppy Disc Assembly” on page 189
“A7 Motherboard Assembly” on page 191
“Card Cage Assemblies” on page 194, which includes:
“GPIB, RS-232, Frequency Extension, DSP, IF” on page 194
“A8 RF Assembly” on page 197
“A8 Sub-assemblies” on page 203, which includes:
“A8A4 LO Amp/IF Switch Assembly” on page 203
“A8A5 Input Attenuator” on page 207
“A8A6 YIG-Tuned Filter/Mixer” on page 204
“A8A2 Second Converter” on page 209
“Input Connector” on page 213
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Chapter 6
Replacing Assemblies
Instrument Outer Case
Instrument Outer Case
Figure 6-2
Outer Case, Rear Frame Removal
Removal
Step 1. Referring to Figure 6-2 disconnect the noise figure analyzer from ac power (1).
Step 2. Remove any adapters or cables (2) connected to the front frame.
Step 3. Carefully place the analyzer on the work surface with the front frame (3) facing
down.
Step 4. Remove the handle (4) as shown in Figure 6-3.
Chapter 6
149
Replacing Assemblies
Instrument Outer Case
Figure 6-3
Handle Removal
Step 5. Remove the 6 screws (5), as shown in Figure 6-4, that hold the rear frame and
outer case in place.
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Chapter 6
Replacing Assemblies
Instrument Outer Case
Figure 6-4
Rear Panel Screw Removal
5
5
5
5
5
5
Step 6. Remove the rear frame assembly.
Step 7. Pull the outer cover off towards the rear of the instrument as shown in Figure 6-5.
Chapter 6
151
Replacing Assemblies
Instrument Outer Case
Figure 6-5
Outer Cover Removal
Replacement
Step 1. Referring to Figure 6-2, carefully place the analyzer on the work surface with the
front frame (3) facing down.
Step 2. Replace the instrument outer case, matching the grill (8) on the bottom of the case
to the bottom of the analyzer.
Step 3. Fit the leading edge of the case completely into the slot (9) on the back of the
front frame assembly.
Step 4. Replace the rear frame assembly, using the 6 screws (5) to fasten the rear frame to
the instrument. Tighten them to 21 inch-pounds.
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Replacing Assemblies
Chassis Cover
Chassis Cover
Removal
Step 1. If you have not previously done so, remove the instrument outer case. Refer to the
removal procedure “Instrument Outer Case” on page 149.
Step 2. Lay the instrument flat as shown in Figure 6-6.
Step 3. Remove the 18 screws (2) and (3) attaching the chassis cover (1) to the chassis.
Step 4. The chassis cover can now be removed from the chassis.
Figure 6-6
Chassis Cover Screw Removal
(5 Places)
(This side)
3
3
1
3
(3 places)
2
2
3
2
3
(5 Places)
(This side)
3
3
3
3
3
3
Chapter 6
153
Replacing Assemblies
Chassis Cover
Figure 6-7
Chassis Cover Replacement
Replacement
Step 1. Position the chassis cover (1) over the instrument as shown in Figure 6-7, then
lower onto the instrument. Ensure all external connectors are not obstructing the
cover.
Step 2. Replace the 18 screws (2) as (3) shown and tighten them to 9 inch-pounds.
Step 3. Replace the outer case. Refer to the replacement procedure “Instrument Outer
Case” on page 149.
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Chapter 6
Replacing Assemblies
A1 Front Frame Assembly
A1 Front Frame Assembly
CAUTION
Use ESD precautions when performing this replacement procedure.
Extension of the Front Frame Assembly
The A1 front frame assembly can be extended from the instrument without
detaching any connections.
Figure 6-8
A1 Front Frame Assembly Removal
Step 1. Remove the instrument outer case. Refer to the removal procedure “Instrument
Outer Case” on page 149.
Chapter 6
155
Replacing Assemblies
A1 Front Frame Assembly
Step 2. Refer to Figure 6-8. With the instrument still on its face, remove the 5 screws (1),
two on the bottom side and three on the top of the instrument. These screws secure
the front frame to the RF assembly and chassis cover.
Step 3. Place the instrument with the top side facing up and remove the remaining 2
screws (2) that secure the front frame subpanel to the chassis.
Step 4. Slide the front frame forward until it catches on the tabs on the sides of the chassis.
Removal
Refer to Figure 6-8. To completely remove the A1 front frame assembly, complete
the “Extension of the Front Frame Assembly” procedure, then continue with the
following steps:
Figure 6-9
Front Frame Ribbon Cable
Step 1. Refer to Figure 6-9. Disconnect the ribbon cable W1(1) from the A1A1 front
panel interface board.
Step 2. Refer to Figure 6-10. Disconnect the smart noise source cable (2) from the A7A2
J104 connector.
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Chapter 6
Replacing Assemblies
A1 Front Frame Assembly
Figure 6-10
Smart Noise Source Cable
2
Step 3. Carefully pull the sides of the front frame assembly away from the chassis and over
the tabs on the chassis.
Step 4. Slide the front frame forward to disengage from the chassis assembly.
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157
Replacing Assemblies
A1 Front Frame Assembly
Replacement
Step 1. Align the A1 front frame assembly rails with the chassis as shown in Figure 6-8.
Step 2. Refer to Figure 6-10. Connect the smart noise source cable (2) to the J104
connector on the A7A2 assembly.
Step 3. Refer to Figure 6-9. Connect the ribbon cable W1 (1) to the front frame assembly.
Step 4. Carefully slide the front frame toward the chassis, assuring the ribbon cable is not
pinched between assemblies, and the RF input and normal noise source connectors
lines up correctly with the openings in the front frame.
Step 5. Refer to Figure 6-8. Replace the screws (1) that secure the front frame to the
chassis. Tighten them to 9 inch-pounds.
Step 6. Replace the outer case. Refer to the replacement procedure for the “Instrument
Outer Case” on page 149.
Step 7. Refer to Chapter 7, “Post-Repair Procedures,” for further information on the
calibration and performance verification tests required.
Figure 6-11
Front Panel Assembly
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Chapter 6
Replacing Assemblies
A1MP16 Nameplate
A1MP16 Nameplate
Removal and Replacement
Step 1. Remove the existing nameplate (1) as shown in Figure 6-12.
Step 2. Clean the surface (2) of any adhesive residue.
Step 3. Peel the backing (3) off the new nameplate.
Step 4. Place the new nameplate (4) as shown.
Figure 6-12
Nameplate Replacement
Chapter 6
159
Replacing Assemblies
Connector Label
Connector Label
CAUTION
Use ESD precautions when performing this replacement procedure.
Removal
Step 1. Remove the instrument outer case. Refer to the removal procedure “Instrument
Outer Case” on page 149.
Step 2. Remove the front frame assembly. Refer to the removal procedure “A1 Front
Frame Assembly” on page 155.
Step 3. Remove the RPG knob. Refer to the removal procedure “A1A1 Front Panel
Interface Board” on page 167.
Step 4. Remove the SNS connector, with a pair of C-clip extractors at the back of the front
panel.
Step 5. Remove the two connector covers from the front panel by pinching them from the
sides (4) and removing them through the front of the front frame assembly. See
Figure 6-13.
Step 6. Peel off the old connector label (1) removing any residual adhesive with a sharp
knife or razor blade. See Figure 6-14.
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Chapter 6
Replacing Assemblies
Connector Label
Figure 6-13
Connector Covers
Chapter 6
161
Replacing Assemblies
Connector Label
Installation
Before installing the new connector label, ensure the surface is free from any
adhesive residue from the old label. Failure to do so may result in an uneven
appearance of the new label.
Step 1. Peel the backing (2) off the new label as show in Figure 6-14.
Step 2. Align and install the label by placing a finger in the SNS Serial Noise Source and
EXT KEYBOARD holes. Observe the alignment of the INPUT and
PROBE POWER holes (3).
Figure 6-14
Connector Label Removal and Installation
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Chapter 6
Replacing Assemblies
Connector Label
TIP
It may be helpful to trim off about 2 mm of the tabs (5) on the connector covers
prior to reinstalling them. This will help in aligning the covers. See Figure 6-13.
Step 3. Reinstall the two connector covers from the front panel by pinching them from the
sides (4) and installing them through the front of the assembly. See Figure 6-13.
Step 4. Align the connector covers so they open downward as shown.
Replacement
Step 1. Re-install or re-attach the front panel interface board. Refer to the replacement
procedure “A1A1 Front Panel Interface Board” on page 167.
Step 2. Inspect the ribbon cables to the front panel interface board to ensure they have not
come loose.
Step 3. Replace the RPG knob. It may be helpful to add a drop of isopropyl alcohol or
water to the RPG to make it easier to press on the shaft.
Step 4. Re-install the front frame assembly. Refer to the replacement procedure “A1 Front
Frame Assembly” on page 155.
Step 5. Re-install the instrument outer case. Refer to the replacement procedure
“Instrument Outer Case” on page 149.
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163
Replacing Assemblies
Front Frame Subassemblies
Front Frame Subassemblies
In order to remove any of the following subassemblies, it is necessary to remove
the A1 front frame assembly from the main chassis. Refer to the removal
procedure “A1 Front Frame Assembly” on page 155.
After the subassembly is replaced, reconnect the front frame to the chassis. Refer
to the replacement procedure for the “A1 Front Frame Assembly” on page 155.
Refer to Chapter 7, “Post-Repair Procedures,” for further information on the
calibration and performance verification tests required after the assembly has been
replaced.
CAUTION
Use ESD precautions when performing the following replacement procedures.
A1A2 Display
Figure 6-15
A1A2 Display Replacement
7
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Chapter 6
Replacing Assemblies
Front Frame Subassemblies
Removal
Refer to Figure 6-15 for the following procedure.
Step 1. Place the front frame assembly face down on the work surface.
Step 2. Disconnect the two 2-wire backlight cables (1) from the front panel interface
inverter board.
Step 3. Refer to Figure 6-15. Disconnect the ribbon cable W3 (2) from the front panel
interface board.
CAUTION
The W3 display ribbon cable connector (2) is delicate. Use a small screwdriver or
similar tool, gently push the lock tabs out from the back of the connector.
Excessive force on the locking tab can break the retaining clips, and if broken,
board replacement is necessary.
Step 4. Remove the 4 screws (3) securing the display (in a bracket) (4) to the front
frame.
Step 5. Carefully lift the display out of the front frame assembly.
Replacement
CAUTION
The display monitor comes with a protective plastic sheet over the glass. Remove
this plastic very slowly to avoid ESD damage.
CAUTION
The display’s surface is very easily scratched. Avoid touching it with your bare
hands or other objects. Use a blower to remove any dust from the display surface.
Step 1. Clean the inside of the lens that is attached to the front frame.
Step 2. Refer to Figure 6-16. Place the display (3) into the front frame assembly. Make
sure that the cables are not pinched between the display and the front frame, and
the W3 ribbon cable is not folded.
Step 3. Replace the 4 screws (3) that secure the display bracket to the front frame.
Tighten them to 9 inch-pounds.
Step 4. Connect the W3 display ribbon cable (2) to the front panel interface board.
TIP
An easy way to insert this delicate cable into the connector is to place your finger
on the cable, in the center of the LCD display, and gently slide the cable toward the
connector until they align. Then, providing guidance with the other hand as
necessary, slide the cable until the end slips into the connector.
Ensure the cable end is seated completely and is aligned straight within the
connector body.
Continue to hold the cable in place with your finger, and with the other hand gently
press the locking tabs (5) into place. See Figure 6-15.
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Replacing Assemblies
Front Frame Subassemblies
NOTE
If you experience display problems, check this connection.
Step 5. Connect the two backlight cables (1) to the front panel interface inverter board.
Figure 6-16
Front Frame Assembly Parts
10
(4 Places)
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Replacing Assemblies
Front Frame Subassemblies
A1A1 Front Panel Interface Board
Removal
Step 1. Refer to Figure 6-17. Remove the media door(1) from the front panel.
Step 2. Insert a flat-blade screwdriver under the RPG knob(2) as shown in Figure 6-17,
and twist it to remove the knob.
Figure 6-17
Removing the Knob
Step 3. Refer to Figure 6-15. Disconnect the two 2-wire backlight cables (1) from the
inverter board.
Step 4. Disconnect the display ribbon cable W3 (2) and the keypad ribbon cable (7)
from the front panel interface board.
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167
Replacing Assemblies
Front Frame Subassemblies
CAUTION
The display ribbon cable connector (2) is delicate. Refer to Figure 6-15. With a
small screwdriver or similar tool, gently push the lock tabs (6) out from the back
of the connector. Excessive force on the locking tab will break the retaining clips,
and if broken, the board’s replacement is necessary.
Step 5. Refer to Figure 6-16. Remove the 4 screws that secure the A1A1 front panel
interface board (10) to the front frame.
Step 6. Remove the front panel interface board from the front frame assembly.
Replacement
Step 1. Place the front panel interface board (10) in the correct position in the front frame
assembly.
Step 2. Replace the 4 screws that secure the board to the front frame. Tighten them to 9
inch-pounds.
Step 3. Connect the ribbon cable W3 (2) to the front panel interface board.
TIP
An easy way to insert this delicate cable into the connector is to place your finger
on the cable, in the center of the LCD display, and gently slide the cable toward the
connector until they align. Then, providing guidance with the other hand as
necessary, slide the cable until the end slips into the connector.
Ensure the cable end is seated completely and is aligned straight within the
connector body.
Continue to hold the cable in place with your finger, and with the other hand gently
press the locking tabs (5) into place. See Figure 6-15.
NOTE
If you experience display problems, check the W3 display connection.
Step 4. Connect the keypad ribbon cable (7) to the front panel interface board.
Step 5. Reconnect the two 2-wire backlight cables (1) to the inverter board.
Step 6. Press the RPG knob onto its control shafts.
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Chapter 6
Replacing Assemblies
Front Frame Subassemblies
Front Panel RPG
Removal/Replacement
Step 1. Remove the front panel interface board. Refer to the removal procedure “A1A1
Front Panel Interface Board” on page 167.
Step 2. Unsolder the appropriate RPG and remove it from the front panel interface board.
Step 3. Place the new RPG in the correct position and resolder the leads.
Step 4. Replace the front panel interface board. Refer to the replacement procedure “A1A1
Front Panel Interface Board” on page 167.
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Replacing Assemblies
Front Frame Subassemblies
Keypad/Flex Circuit
Removal
Step 1. Remove the RPG knob.
TIP
To facilitate knob removal, slide any flat flexible material (such as a flat-blade
screwdriver) under the knob and pry upward, refer to Figure 6-17.
Step 2. Remove the front panel interface board. Refer to the removal procedure “A1A1
Front Panel Interface Board” on page 167.
Step 3. Refer to Figure 6-16. Remove the 4 screws (1) that secure the display to the front
frame.
Step 4. Remove the display assembly (2) then the support bracket (3).
Step 5. Remove the 6 screws (8) securing the subpanel assembly (9) to the front frame.
Step 6. Remove the subpanel assembly (9).
Step 7. Lift out the keypad/flex circuit (4) and the main keypad (7). Be careful to avoid
touching the keypad contacts with your fingers.
Replacement
Step 1. Refer to Figure 6-16. Place the main keypad (7) so it lays flat in the front frame
(6). Be careful to avoid touching the keypad contacts with your fingers.
Step 2. Insert the flex circuit (4) so it aligns with the pegs on the front frame and lies flat.
Step 3. Replace the subpanel (9), and secure with the 6 screws (8). Tighten them to 9
inch-pounds.
NOTE
If you are putting in a new flex circuit, it will need to be preformed in order to fit
properly in the front frame. Slightly bend the circuit along the slits in two places
between the main key section and the display section to conform to the contours of
the front frame. Be careful to not bend the circuit too much (no more than a 90°
angle), and do not crease it. This can damage the traces in the flex circuit.
Step 4. Replace the support bracket (3), along with the display (2) and secure with the 4
screws (1). Tighten them to 9 inch-pounds.
Step 5. Replace the front panel interface board. Refer to the replacement procedure “A1A1
Front Panel Interface Board” on page 167.
Step 6. Replace the RPG knobs.
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Front Frame Subassemblies
A1A3MP9 Lens/Keypad Assembly
Removal
NOTE
The lens/keypad assembly is pressed into place, using a strong adhesive instead of
hardware. It is made of a plastic material and will bend but not break.
Step 1. Remove the keypad/flex circuit. Refer to the removal procedure “Keypad/Flex
Circuit” on page 170.
Step 2. To remove the lens/keypad from the front frame, apply pressure from the front
side. Using both thumbs, press in the corner of the lens as shown in Figure 6-18
until it pops out.
Figure 6-18
Lens Removal
Replacement
Step 1. Remove the paper covering the adhesive on the lens/keypad assembly.
Step 2. Carefully fit the new lens/keypad assembly into place in the front frame. Press
along the edges of the lens from the inside to adhere it to the front frame.
Step 3. Make sure the inside of the lens is clean from contaminants, such as lint and
fingerprints, before proceeding.
Step 4. Replace the main keypad, flex circuit, and subpanel assembly (with the display and
front panel interface board attached). Refer to the replacement procedure
“Keypad/Flex Circuit” on page 170.
Step 5. Replace the front panel interface board. Refer to the replacement procedure “A1A1
Front Panel Interface Board” on page 167.
Step 6. After the front frame is reattached to the chassis, remove the protective plastic
covering from the lens.
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Replacing Assemblies
Front Frame Subassemblies
A1A2DS1/A1A2DS2 Display Backlight
Removal
Step 1. Remove the display. Refer to the removal procedure “A1A2 Display” on page 164.
Step 2. Figure 6-19. Loosen 2 frame retaining screws (1 turn) adjacent to the backlight
being removed. Press the black locking tab (wire end) outward, and pull the
backlight (1) out carefully. Repeat the operation for the other backlight.
Figure 6-19
Display Backlight Replacement
Replacement
CAUTION
Do not touch the bulb encased in the plastic backlight assembly.
Step 1. Insert the new backlight assembly (1) by sliding it into the display, non-wired end
first, taking care not to force it. It is keyed so it only fits one way. Slide it all the
way in to the end of the casing.
NOTE
It is recommended that both backlights be replaced at the same time, even though
only one has failed. The remaining (functioning) backlight will likely fail shortly
after the first backlight fails.
Step 2. Tighten the 4 screws that secure the backlight to the frame. Tighten them to
9 inch-pounds.
Step 3. Replace the display. Refer to the replacement procedure “A1A2 Display” on page
164.
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Front Frame Subassemblies
A1MP11 Media Door/Bezel
Step 1. The media door snaps on and off of the media bezel.
Step 2. Refer to Figure 6-20. To remove the media bezel (1), it is necessary to remove the
front frame. Refer to the removal procedure “A1 Front Frame Assembly” on page
155.
Step 3. The bezel snaps into place. It can be removed by pressing the tabs together from
the inside and pushing the bezel out of the front frame.
Figure 6-20
Media Door/Bezel
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Replacing Assemblies
MP7 Vibration Support Bar
MP7 Vibration Support Bar
Removal
Step 1. Referring to Figure 6-21, loosen, but do not remove, all 9 of the screws (1)
securing the boards and blank panels at the rear of the chassis.
CAUTION
The vibration support bar is fragile. When removing the bar use caution to avoid
breaking it.
Step 2. On the vibration support bar, press in the locking tabs (2) and rotate the bar (3)
upward. Remove the bar by sliding it out of the holes in each of the assemblies and
lifting it up.
Figure 6-21
Removing the Vibration Support Bar
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Chapter 6
Replacing Assemblies
MP7 Vibration Support Bar
Replacing the Vibration Support Bar
Step 1. Referring to Figure 6-22, replace the vibration support bar (1) as follows:
1. Position the vibration support bar (1) as shown and insert the hook (2) into
the A2 front end assembly’s support arm.
2. Engage each hook (3) of the other assemblies or blank panels.
3. After you position each of the assemblies or blank panels, rotate (4) the
support bar to lock them in place.
4. Referring to Figure 6-23, make sure that the tab (1) is positioned in the slot of
the power supply chassis and the vibration bar is fully seated and locked (2)
into position.
CAUTION
The vibration support bar can easily be broken if it is forced. Install it with care.
Step 2. Refer to Figure 6-21. Tighten the 9 screws (1) that were loosened in the removal
procedure to 9 inch-pounds.
Figure 6-22
Installing the Vibration Support Bar
Chapter 6
175
Replacing Assemblies
MP7 Vibration Support Bar
Figure 6-23
Seating the Vibration Support Bar
176
Chapter 6
Replacing Assemblies
A3 Microwave Front End Assembly
A3 Microwave Front End Assembly
(N8974A and 8975A)
CAUTION
Use ESD precautions when performing this replacement procedure.
Removal
Step 1. Remove the instrument chassis cover. Refer to the removal procedure “Chassis
Cover” on page 153.
Step 2. Extend the A1 front frame assembly. Refer to the extension procedure “Extension
of the Front Frame Assembly” on page 155.
Step 3. Refer to Figure 6-24. Remove the 9 screws (1), (6 from the side, 3 from the top).
Step 4. Disconnect the W6 semi-rigid from the A3J1 connector on the microwave front
end.
Step 5. Disconnect the W7 semi-rigid from the A3J2 connector on the microwave front
end.
Step 6. Disconnect the W14 semi-rigid from the A3J5 connector on the microwave front
end.
Step 7. Carefully pull up on the microwave front end assembly to remove it from the
motherboard connector.
Figure 6-24
A3 Microwave Front End Hardware
1
(3 PLACES)
1 (6 PLACES)
Chapter 6
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Replacing Assemblies
A3 Microwave Front End Assembly
Replacement
CAUTION
Use ESD precautions when performing the following replacement procedures.
Step 1. Carefully plug the microwave front end assembly into the motherboard.
Step 2. Replace the 3 semi-rigids to the microwave front end. Torque to 5 inch-pounds.
Step 3. Refer to Figure 6-24. Replace the 9 screws. Tighten them to 9 inch-pounds.
Step 4. Reconnect the A1 front frame to the chassis. Refer to the replacement procedure
“A1 Front Frame Assembly” on page 155.
Step 5. Replace the chassis cover. Refer to the replacement procedure “Chassis Cover” on
page 153.
Step 6. Replace the outer case. Refer to the replacement procedure “Instrument Outer
Case” on page 149.
Step 7. Refer to Chapter 7, “Post-Repair Procedures,” for further information on the
calibration and performance verification tests required after the assembly has been
replaced.
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Chapter 6
Replacing Assemblies
A2 RF Front End
A2 RF Front End
CAUTION
Use ESD precautions when performing this replacement procedure.
Removal
Step 1. Remove the instrument chassis cover. Refer to the removal procedure “Chassis
Cover” on page 153.
Step 2. Remove the vibration support bar. Refer to the removal procedure “MP7 Vibration
Support Bar” on page 174.
Step 3. Refer to Figure 6-25. Remove the 2 screws (1) securing the A2 front end
assembly to the chassis. (On the N8974A and N8975A models remove 4 screws.)
Step 4. Disconnect the W15 coaxial cable from the A2J3 connector on the front end
assembly.
Step 5. Disconnect the 2 semi-rigids W8 and W13 from the A2J3 and A2J1 respectively
on the front end assembly.
Step 6. Carefully lift the front end assembly to remove it from the motherboard connector.
Figure 6-25
A2 Front End Assembly
Chapter 6
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Replacing Assemblies
A2 RF Front End
Replacement
Step 1. Carefully plug the front end assembly into the motherboard.
Step 2. Refer to Figure 6-25. Replace the 2 screws (1) that secure the front end assembly
to the chassis. Tighten them to 9 inch-pounds. (On the N8974A and N8975A
models replace 4 screws.)
Step 3. Connect the 2 semi-rigids W8 and W13 to the front end assembly. Torque to 5
inch-pounds.
Step 4. Connect the W15 coaxial cable to the front end assembly. Torque to 5 inch-pounds.
Step 5. Replace the vibration support bar. Refer to the replacement procedure “MP7
Vibration Support Bar” on page 174.
Step 6. Replace the chassis cover. Refer to the replacement procedure “Chassis Cover” on
page 153.
Step 7. Replace the outer case. Refer to the replacement procedure “Instrument Outer
Case” on page 149.
Step 8. Refer to Chapter 7, “Post-Repair Procedures,” for further information on the
calibration and performance verification tests required after the assembly has been
replaced.
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Chapter 6
Replacing Assemblies
A4 Processor Assembly
A4 Processor Assembly
CAUTION
Use ESD precautions when performing this replacement procedure.
Removal
Step 1. Remove the instrument chassis cover. Refer to the removal procedure “Chassis
Cover” on page 153.
Step 2. Remove the vibration support bar. Refer to the removal procedure “MP7 Vibration
Support Bar” on page 174.
Step 3. Refer to Figure 6-26. Remove the single screw (1) securing the A4 processor
assembly to the chassis.
Step 4. Disconnect the front panel ribbon cable W1 (2) from the processor assembly.
Step 5. Carefully lift the processor assembly to remove it from the motherboard connector.
Figure 6-26
A4 Processor Assembly
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Replacing Assemblies
A4 Processor Assembly
Replacement
Step 1. Carefully plug the processor assembly into the motherboard.
Step 2. Refer to Figure 6-26. Replace the single screw (1) that secures the processor
assembly to the chassis, but do not fully tighten.
Step 3. Reconnect the front panel ribbon cable W1(2) to the processor assembly.
Step 4. Replace the vibration support bar. Refer to the replacement procedure “MP7
Vibration Support Bar” on page 174.
Step 5. Tighten the screw (1) to 9 inch-pounds.
Step 6. Replace the chassis cover. Refer to the replacement procedure “Chassis Cover” on
page 153.
Step 7. Replace the outer case. Refer to the replacement procedure “Instrument Outer
Case” on page 149.
Step 8. Refer to Chapter 7, “Post-Repair Procedures,” for further information on the
calibration and performance verification tests required after the assembly has been
replaced.
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Chapter 6
Replacing Assemblies
A4A1 and A4A2 Flash and DRAM SIMM
A4A1 and A4A2 Flash and DRAM SIMM
CAUTION
Use ESD precautions when performing this replacement procedure.
Removal and Replacement
Step 1. Remove the A4 processor assembly. Refer to the removal procedure “A4 Processor
Assembly” on page 181.
Step 2. Refer to Figure 6-27. Carefully remove the flash SIMM (1) or the DRAM SIMM
(2).
Step 3. Replace the flash SIMM (1) or the DRAM SIMM (2).
Step 4. Replace the A4 processor assembly. Refer to the replacement procedure “A4
Processor Assembly” on page 181.
Step 5. Refer to Chapter 7, “Post-Repair Procedures,” for further information on the
calibration and performance verification tests required after the assembly has been
replaced.
Figure 6-27
Flash SIMM and DRAM SIMM
NOTE
Ensure that after either of these parts have been replaced that you follow the
procedure in “Firmware Installation Procedure” on page 10 and reload the
firmware.
Chapter 6
183
Replacing Assemblies
A4BT1 Battery
A4BT1 Battery
CAUTION
Use ESD precautions when performing this replacement procedure.
WARNING
There is a danger of explosion if the battery is incorrectly replaced. Replace
only with the same or equivalent type recommended. Discard used batteries
according to manufacturer’s instruction.
DO NOT THROW BATTERIES AWAY BUT
COLLECT AS SMALL CHEMICAL WASTE.
sk780a
Removal and Replacement
Step 1. Remove the A4 processor assembly from the instrument. Refer to the removal
procedure “A4 Processor Assembly” on page 181.
Step 2. Refer to Figure 6-28. Gently pry the A4BT1 lithium battery from the processor
board.
Step 3. Insert the new battery, ensuring proper polarity as indicated on the socket.
Step 4. Replace the processor assembly in the instrument. Refer to the replacement
procedure “A4 Processor Assembly” on page 181.
Step 5. Refer to Chapter 7, “Post-Repair Procedures,” for further information on the
calibration and performance verification tests required after the assembly has been
replaced.
Figure 6-28
Processor Battery Location
184
Chapter 6
Replacing Assemblies
A5 Power Supply
A5 Power Supply
CAUTION
Use ESD precautions when performing this replacement procedure.
Removal
Step 1. Remove the instrument chassis cover. Refer to the removal procedure “Chassis
Cover” on page 153.
Step 2. Remove the vibration support bar. Refer to the removal procedure “MP7 Vibration
Support Bar” on page 174.
Step 3. Extend the A1 front frame assembly. Refer to the extension procedure “A1 Front
Frame Assembly” on page 155.
Step 4. Refer to Figure 6-29. Remove the single screw (1) securing the A5 power supply
assembly to the chassis at the rear of the instrument.
Step 5. Carefully pull up on the power supply assembly to remove it from motherboard
connector.
Figure 6-29
A5 Power Supply
1
Chapter 6
185
Replacing Assemblies
A5 Power Supply
Replacement
Step 1. Carefully plug the A5 power supply assembly into the motherboard.
Step 2. Refer to Figure 6-29. Replace the single screw (1) that secures the power supply
to the chassis, but do not fully tighten.
NOTE
Ensure you change the switch at the rear of the A5 power supply, so the power is
set to PWR NORM. Refer to the Overview of the Rear Panel section of the User’s
Guide for information on this switch.
Step 3. Reconnect the front frame assembly to the chassis. Refer to the replacement
procedure “A1 Front Frame Assembly” on page 155.
Step 4. Replace the vibration support bar. Refer to the replacement procedure “MP7
Vibration Support Bar” on page 174.
Step 5. Tighten the screw (1) to 9 inch-pounds.
Step 6. Replace the chassis cover. Refer to the replacement procedure “Chassis Cover” on
page 153.
Step 7. Replace the outer case. Refer to the replacement procedure “Instrument Outer
Case” on page 149.
Step 8. Refer to Chapter 7, “Post-Repair Procedures,” for further information on the
calibration and performance verification tests required after the assembly has been
replaced.
186
Chapter 6
Replacing Assemblies
A5B1 Fan
A5B1 Fan
CAUTION
Use ESD precautions when performing this replacement procedure.
Removal
Step 1. Remove the power supply assembly. Refer to the removal procedure “A5 Power
Supply” on page 185.
Step 2. Unplug the fan wires (2) from the power supply board connector (3) inside the
assembly. Refer to Figure 6-30.
Step 3. Refer to Figure 6-30. Remove the 4 screws (1) securing the top cover to the power
supply assembly.
Figure 6-30
Power Supply Cover Removal
Step 4. Remove the top cover.
Step 5. Locate the 4 plastic rivets (5) that secure the fan (6) to the cover.
Step 6. The rivets are not reusable and need to be cut off in order to change the fan.
Step 7. The fan can be removed after the 4 rivets are cut out.
Chapter 6
187
Replacing Assemblies
A5B1 Fan
Replacement
Step 1. Position the fan on the outside of the power supply cover so that the fan wires go
through the opening of the cover and are aligned with the notch. Be careful not to
pinch the fan wires against the cover.
NOTE
Be careful to install the fan so that the arrow indicating the direction of the air flow,
(on the body of the fan), is pointing away from the cover. This will ensure the
proper air flow through the instrument and exiting through the side panel.
Step 2. Refer to Figure 6-30. Assemble the bushing, grommet, and rivet as shown in 4
places.
Step 3. Replace the power supply cover, with fan, on the power supply assembly. Make
sure the lip on the top cover catches underneath (4) the bottom cover.
Step 4. Replace the 4 screws (1) that secure the top cover to the power supply assembly.
Tighten them to 9 inch-pounds.
Step 5. Plug the fan connector into the power supply board.
Step 6. Replace the power supply assembly. Refer to the replacement procedure “A5
Power Supply” on page 185.
Step 7. Refer to Chapter 7, “Post-Repair Procedures,” for further information on the
calibration and performance verification tests required after the assembly has been
replaced.
188
Chapter 6
Replacing Assemblies
A6 Floppy Disc Assembly
A6 Floppy Disc Assembly
CAUTION
Use ESD precautions when performing this replacement procedure.
Removal
Step 1. Remove the instrument chassis cover. Refer to the removal procedure “Chassis
Cover” on page 153.
Step 2. Extend the A1 front frame. Refer to the extension procedure “Extension of the
Front Frame Assembly” on page 155.
Step 3. Refer to Figure 6-31. Remove the 4 screws (1) securing the A6 floppy assembly
(2) to the side frame.
Step 4. Carefully pull up on the floppy assembly to remove it from the motherboard
connector.
Figure 6-31
A6 Floppy Disc Assembly Removal
Chapter 6
189
Replacing Assemblies
A6 Floppy Disc Assembly
Replacement
Step 1. Carefully plug the A6 floppy assembly into the motherboard.
Step 2. Refer to Figure 6-31. Replace the 4 screws (1) that secure the floppy assembly
(2) to the side chassis. Tighten them to 9 inch-pounds.
Step 3. Reconnect the A1 Front Frame to the chassis. Refer to the replacement procedure
“A1 Front Frame Assembly” on page 155.
Step 4. Replace the chassis cover. Refer to the replacement procedure “Chassis Cover” on
page 153.
Step 5. Replace the outer case. Refer to the replacement procedure “Instrument Outer
Case” on page 149.
Step 6. Refer to Chapter 7, “Post-Repair Procedures,” for further information on the
calibration and performance verification tests required after the assembly has been
replaced.
190
Chapter 6
Replacing Assemblies
A7 Motherboard Assembly
A7 Motherboard Assembly
CAUTION
Use ESD precautions when performing this replacement procedure.
Removal
Step 1. Remove the instrument outer case. Refer to the removal procedure “Instrument
Outer Case” on page 149.
Step 2. Remove the instrument chassis cover. Refer to the removal procedure “Chassis
Cover” on page 153.
Step 3. Extend the A1 front frame. Refer to the extension procedure “A1 Front Frame
Assembly” on page 155.
Step 4. Remove the vibration support bar. Refer to the removal procedure “MP7 Vibration
Support Bar” on page 174.
Step 5. Remove the A6 floppy drive assembly. Refer to the removal procedure“A6 Floppy
Disc Assembly” on page 189.
Step 6. On models N8974A and N8975A, remove the A3 microwave front end assembly.
Refer to the removal procedure “A3 Microwave Front End Assembly” on page
177.
Step 7. Remove the A2 front end assembly. Refer to the removal procedure “A2 RF Front
End” on page 179.
Step 8. Remove the A4 processor assembly. Refer to the removal procedure “A4 Processor
Assembly” on page 181.
Step 9. Remove the A5 power supply assembly. Refer to the removal procedure “A5
Power Supply” on page 185.
Step 10. Remove all card cage assemblies from the motherboard. Refer to the removal
procedure “Card Cage Assemblies” on page 194.
Chapter 6
191
Replacing Assemblies
A7 Motherboard Assembly
Figure 6-32
A7 Motherboard Removal
Step 11. Refer to Figure 6-32. Disconnect the RF ribbon cable W4 (1) from the
motherboard (2).
Step 12. Remove the 3 screws (3) as indicated in Figure 6-32.
Step 13. Slide the motherboard sideways to disengage the shoulder lock standoffs (4), and
lift the motherboard out of the chassis.
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Chapter 6
Replacing Assemblies
A7 Motherboard Assembly
Replacement
Step 1. Refer to Figure 6-32. Carefully place the motherboard (2) into the chassis.
Step 2. Slide the motherboard sideways to engage the shoulder locks (4) on the chassis.
Step 3. Replace the 3 screws (3) that secure the motherboard to the chassis. Tighten them
to 9 inch-pounds.
Step 4. Refer to Figure 6-32. Connect the RF ribbon cable W4 (1) to the motherboard.
Step 5. Replace the A5 power supply assembly. Refer to the replacement procedure “A5
Power Supply” on page 185.
Step 6. Replace the A4 processor assembly. Refer to the replacement procedure “A4
Processor Assembly” on page 181.
Step 7. Replace the A2 front end assembly. Refer to the replacement procedure “A2 RF
Front End” on page 179.
Step 8. Replace the A3 front end assembly, if applicable. Refer to the replacement
procedure “A3 Microwave Front End Assembly” on page 177.
Step 9. Replace the A6 floppy disc assembly. Refer to the replacement procedure “A6
Floppy Disc Assembly” on page 189.
Step 10. Replace the card cage assemblies. Refer to the replacement procedure “Card Cage
Assemblies” on page 194.
Step 11. Reconnect the A1 front frame to the chassis. Refer to the replacement procedure
“A1 Front Frame Assembly” on page 155.
Step 12. Replace the vibration support bar. Refer to the replacement procedure “MP7
Vibration Support Bar” on page 174.
Step 13. Tighten all the screws (1) to 9 inch-pounds. Refer to Figure 6-34.
Step 14. Replace the chassis cover. Refer to the replacement procedure “Chassis Cover” on
page 153.
Step 15. Replace the outer case. Refer to the replacement procedure “Instrument Outer
Case” on page 149.
Step 16. Refer to Chapter 7, “Post-Repair Procedures,” for further information on the
calibration and performance verification tests required after the assembly has been
replaced.
Chapter 6
193
Replacing Assemblies
Card Cage Assemblies
Card Cage Assemblies
GPIB, RS-232, Frequency Extension, DSP, IF
Use ESD precautions when performing this replacement procedure.
CAUTION
The following procedure can be used for all of the Card Cage assemblies:
Figure 6-33
•
A7A1 GPIB/Parallel Assembly (1)
•
A7A2 RS-232/SIB Assembly (2)
•
A7A3 Frequency Extension Assembly (N8974A and N8975A) (3)
•
A7A4 DSP Assembly (4)
•
A7A5 IF Assembly (5)
Card Cage Assembly Locations
1
2
3
4
5
Removal
Step 1. Remove the instrument chassis cover. Refer to the removal procedure “Chassis
Cover” on page 153.
Step 2. Remove the vibration support bar. Refer to the removal procedure “MP7 Vibration
Support Bar” on page 174.
Step 3. Locate the assembly to be removed.
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Chapter 6
Replacing Assemblies
Card Cage Assemblies
Step 4. Refer to Figure 6-34. Remove the single screw (1) securing the card cage
assembly to the chassis.
Figure 6-34
Card Cage Hardware
3
Step 5. Remove the assembly and disconnect any cables, for example, when removing the
DSP assembly, disconnect the ribbon cable (2) and the clock cable (3) from the
DSP assembly
Step 6. Carefully pull up on the assembly to remove it from the motherboard connector.
Chapter 6
195
Replacing Assemblies
Card Cage Assemblies
Replacement
Step 1. Carefully plug the assembly into the motherboard.
Step 2. Replace the assembly and reconnect any cables, for example, replace the DSP
assembly, connect the ribbon cable (2) and the clock cable (3) to the DSP
assembly.
Step 3. Refer to Figure 6-34. Replace the single screw (1) that secures the card cage
assembly to the chassis, but do not fully tighten.
Step 4. Replace the vibration support bar. Refer to the replacement procedure “MP7
Vibration Support Bar” on page 174.
Step 5. Tighten the screw (1) to 9 inch-pounds.
Step 6. Replace the chassis cover. Refer to the replacement procedure “Chassis Cover” on
page 153.
Step 7. Replace the outer case. Refer to the replacement procedure “Instrument Outer
Case” on page 149.
Step 8. Refer to Chapter 7, “Post-Repair Procedures,” for further information on the
calibration and performance verification tests required after the assembly has been
replaced.
196
Chapter 6
Replacing Assemblies
A8 RF Assembly
A8 RF Assembly
CAUTION
Use ESD precautions when performing this replacement procedure.
Removal
Step 1. Remove instrument outer case. Refer to the removal procedure “Instrument Outer
Case” on page 149
Step 2. Remove the instrument chassis cover. Refer to the removal procedure “Chassis
Cover” on page 153.
Step 3. Remove the A1 front frame assembly. Refer to the removal procedure “A1 Front
Frame Assembly” on page 155.
Figure 6-35
RF Assembly Ribbon Cable
1
Step 4. Referring to Figure 6-36. Remove the 4 screws (1) and the shock spreader
assembly bar (2).
Chapter 6
197
Replacing Assemblies
A8 RF Assembly
Figure 6-36
Shock Spreader Bar
2
1
Step 5. Disconnect the ribbon cable W4 (1) from the rear of the A8 RF assembly, shown
in Figure 6-35, and the ribbon cable W5 from the front of the assembly.
Step 6. Refer to Figure 6-37. Disconnect the coaxial cable W33 (1) from the SIB (A7A2)
assembly.
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Chapter 6
Replacing Assemblies
A8 RF Assembly
Figure 6-37
SIB Noise Source Cable
1
Step 7. On models N8974A and N8975A, disconnect the ribbon cable W16 from the
Frequency Extension (A7A3) assembly.
Step 8. Disconnect the 2 semi-rigid cables W13 and W8, and 1 coax cable W15 from the
front end (A2) assembly. Refer to the “A2 RF Front End” on page 179.
Step 9. On models N8974A and N8975A, disconnect the 3 semi-rigid cables W6, W7, and
W14 from the microwave front end (A3) assembly. Refer to the “A3 Microwave
Front End Assembly” on page 177.
Step 10. Disconnect the coaxial cable W31 from the A8P5 connector on the RF Assembly
(A8).
Step 11. Referring to Figure 6-38, position the instrument upside down and remove the 6
screws (1) marked “RF Deck” securing the RF assembly (A8) to the chassis.
Chapter 6
199
Replacing Assemblies
A8 RF Assembly
Figure 6-38
A8 RF Assembly
1
1
1
1
1
1
Step 12. Carefully lift the RF assembly from the chassis.
CAUTION
The cables and assemblies are easily damaged. Once removed, it is best to lay the
RF assembly flat on a work surface. Do not rest it against any of the RF assemblies
or cables.
Step 13. On models N8974A and N8975A, remove the A8A4 LOIS assembly and all
connections. Refer to the removal procedure “A8A4 LO Amp/IF Switch
Assembly” on page 203.
Step 14. On models N8974A and N8975A, remove the A8A6 YIG and all connections.
Refer to the removal procedure “A8A6 YIG-Tuned Filter/Mixer” on page 204.
Step 15. Remove the A8FL1 low pass filter and W12 from the A8A5 input attenuator.
Step 16. Remove the A8A5 input attenuator and all connections. Refer to the removal
procedure “A8A5 Input Attenuator” on page 207.
Step 17. Replace the A8MP4 metal bracket, ensure the W5 ribbon cable goes underneath
this bracket and is connected to the A8P4 connector on the A8 RF assembly.
Step 18. Remove the A8A2 second Converter and all connections. Refer to the removal
procedure “A8A2 Second Converter” on page 209.
Step 19. Remove the 4 screws holding on the A8MP2 metal bracket.
Step 20. Pull the bracket to separate it for the A8 Assembly.
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Chapter 6
Replacing Assemblies
A8 RF Assembly
Replacement
Step 1. Position the A8MP2 metal bracket such that the two adhesive materials link.
Figure 6-39
Adhesive Material Location
1
Step 2. Replace the 4 screws holding on the A8MP2 metal bracket.
Step 3. Replace the A8A2 Second Converter and all connections. Refer to the replacement
procedure “A8A2 Second Converter” on page 209.
Step 4. Replace the A8MP4 (metal bracket), ensure the W5 ribbon cable is below this
bracket and is connected to the A8P4 connector on the A8 RF assembly.
Step 5. Replace the A8A5 input attenuator and all connections. Refer to the replacement
procedure “A8A5 Input Attenuator” on page 207.
Step 6. Replace the A8FL1 low pass filter and W12 to the A8A5 input attenuator.
Step 7. Replace the A8A6 YIG and all connections. Refer to the replacement procedure
“A8A6 YIG-Tuned Filter/Mixer” on page 204.
Step 8. Replace the A8A4 LOIS and all connections. Refer to the replacement procedure
“A8A4 LO Amp/IF Switch Assembly” on page 203.
Chapter 6
201
Replacing Assemblies
A8 RF Assembly
Step 9. Position the A8 RF assembly resting on the work surface, and lower the card cage
assembly onto the RF assembly taking care not to pinch any cables.
Step 10. Referring to Figure 6-38, replace the 6 screws (1) securing the RF assembly to the
chassis, tighten them to 9 inch-pounds.
Step 11. Reconnect the coaxial cable W31 to the A8P5 connector on the RF Assembly.
Step 12. On models N8974A and N8975A, reconnect the 3 semi-rigid cables W6, W7, and
W14 to the microwave front end (A3) assembly. Refer to the “A3 Microwave Front
End Assembly” on page 177.
Step 13. Reconnect the 2 semi-rigid cables W13 and W8, and 1 coax cable W15 to the front
end (A2) assembly. Refer to the “A2 RF Front End” on page 179.
Step 14. On models N8974A and N8975A, reconnect the W16 ribbon cable to A7A3
frequency extension assembly and the A8A6 YIG and the A8A4 LOIS.
Step 15. Refer to Figure 6-36. Replace the shock spreader assembly bar (2), and tighten
the 4 screws. (1) to 9 inch-pounds.
Step 16. Refer to Figure 6-37. Reconnect the coaxial cable W33 (1) to the SIB A7A2
assembly.
Step 17. Reconnect the ribbon cable W4 (1) from the rear of the A8 RF assembly, shown
in Figure 6-35, and the ribbon cable W5 to the front of the assembly.
Step 18. Replace the A1 front frame assembly. Refer to the replacement procedure “A1
Front Frame Assembly” on page 155.
Step 19. Replace the instrument chassis cover. Refer to the replacement procedure “Chassis
Cover” on page 153.
Step 20. Replace instrument outer case. Refer to the replacement procedure “Instrument
Outer Case” on page 149.
Step 21. Refer to Chapter 7, “Post-Repair Procedures,” for further information on the
calibration and performance verification tests required after the assembly has been
replaced.
202
Chapter 6
Replacing Assemblies
A8 Sub-assemblies
A8 Sub-assemblies
A8A4 LO Amp/IF Switch Assembly
(N8974A and N8975A)
CAUTION
Use ESD precautions when performing this replacement procedure.
NOTE
The LO amplifier and IF switch (LOIS) assembly can be removed without
removing the RF assembly.
Removal
Step 1. Remove the instrument chassis cover. Refer to the removal procedure “Chassis
Cover” on page 153.
Step 2. Remove the A1 front frame assembly. Refer to the removal procedure “A1 Front
Frame Assembly” on page 155.
Step 3. Referring to Figure 6-40, disconnect the 2 semi-rigid cables W24 and W23 (1)
and the 2 Flexible coaxial cables W20 and W21 (2) from the A8A4 assembly.
Step 4. Referring to Figure 6-40, disconnect the 50 ohm loads (3) from the J3 and J4
connectors on the A8A4 assembly.
Step 5. Disconnect the frequency extension ribbon cable W16 (4).
Step 6. Remove the 3 screws (5) and remove the A8A4 assembly.
Figure 6-40
Removing the LO Amplifier/IF Switch Assembly
1
1
2
3
4
5
Chapter 6
203
Replacing Assemblies
A8 Sub-assemblies
Replacement
CAUTION
Use care not to pinch any cables during reassembly.
Step 1. Referring to Figure 6-40, replace the A8A4 assembly and secure with the 3 screws
(5). Tighten them to 9 inch-pounds.
Step 2. Reconnect the frequency extension ribbon cable W16 (4).
Step 3. Referring to Figure 6-40, reconnect the 50 ohm loads (3) to the J3 and J4
connectors on the A8A4 assembly. Torque the SMA connectors to 8 inch-pounds.
Step 4. Referring to Figure 6-40, reconnect the 2 flexible coaxial cables W20 and W21
(2) and the 2 semi-rigid cables W24 and W23 (1) to the A8A4 assembly.
Torque the 2 semi-rigid cables connectors to 5 inch-pounds.
Step 5. Replace the A1 front frame assembly. Refer to the replacement procedure “A1
Front Frame Assembly” on page 155.
Step 6. Replace the instrument chassis cover. Refer to the replacement procedure “Chassis
Cover” on page 153.
Step 7. Refer to Chapter 7, “Post-Repair Procedures,” for further information on the
calibration and performance verification tests required after the assembly has been
replaced.
A8A6 YIG-Tuned Filter/Mixer
(N8974A and N8975A)
CAUTION
Use ESD precautions when performing this replacement procedure.
NOTE
The YIG-Tuned filter/mixer assembly can be removed without removing the RF
assembly.
Removal
Step 1. Remove the instrument chassis cover. Refer to the removal procedure “Chassis
Cover” on page 153.
Step 2. Extend the A1 front frame assembly. Refer to the removal procedure “Extension of
the Front Frame Assembly” on page 155.
Step 3. Referring to Figure 6-41, disconnect the 2 semi-rigid cables W14 and W24 (1)
and the flexible coaxial cable W20 (2) from the A8A6 assembly.
Step 4. Referring to Figure 6-41, disconnect the frequency extension ribbon cable W16
(3).
Step 5. Referring to Figure 6-41, remove the 2 screws (4) from the assembly bracket.
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Chapter 6
Replacing Assemblies
A8 Sub-assemblies
Figure 6-41
YIG Tuned Mixer Cables and Screw Locations
1
4
2
3
Step 6. Pull on the card cage to aid the removal of the A8A6 assembly from the assembly
bracket, as shown in Figure 6-42.
Figure 6-42
YIG Tuned Mixer Removal
Chapter 6
205
Replacing Assemblies
A8 Sub-assemblies
Replacement
CAUTION
Do not to overtighten the SMA connections to the YIG-tuned filter/mixer
assembly. If the connectors are broken loose, the assembly must be returned to the
factory for repair.
Step 1. Refer to Figure 6-42. Replace the A8A6 YIG-tuned filter/mixer assembly onto the
assembly bracket.
Step 2. Referring to Figure 6-41, replace the 2 screws (4) to the assembly bracket, tighten
them to 9 inch-pounds.
Step 3. Reconnect the frequency extension ribbon cable W16 (3).
Step 4. Reconnect the flexible coaxial cable W20 (2) to the A8A6 assembly.
Step 5. Referring to Figure 6-41, reconnect the 2 semi-rigid cables W14 and W24 (1) and
tighten them to 8 inch-pounds with a 5/16” wrench
Step 6. Replace the A1 front frame assembly. Refer to the replacement procedure “A1
Front Frame Assembly” on page 155.
Step 7. Replace the instrument chassis cover. Refer to the replacement procedure “Chassis
Cover” on page 153.
Step 8. Align the YTF using the procedure described in “Align YTF” on page 21.
Step 9. Refer to Chapter 7, “Post-Repair Procedures,” for further information on the
calibration and performance verification tests required after the assembly has been
replaced.
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Chapter 6
Replacing Assemblies
A8 Sub-assemblies
A8A5 Input Attenuator
Use ESD precautions when performing this replacement procedure.
CAUTION
Removal
Step 1. Remove the instrument chassis cover. Refer to the removal procedure “Chassis
Cover” on page 153.
Step 2. Remove the A1 front frame assembly. Refer to the removal procedure “A1 Front
Frame Assembly” on page 155.
Step 3. On models N8974A and N8975A, remove the A8A4 LO amplifier and IF switch
(LOIS) assembly. Refer to the removal procedure “A8A4 LO Amp/IF Switch
Assembly” on page 203.
Step 4. On models N8974A and N8975A, remove the A8A6 YIG-Tuned filter/mixer
assembly. Refer to the removal procedure “A8A6 YIG-Tuned Filter/Mixer” on
page 204.
Step 5. Refer to Figure 6-43. Disconnect the ribbon cable W5 (1) from the A8A5 input
attenuator.
Step 6. Refer to Figure 6-43. Disconnect the 2 semi-rigid cables W12 and W13 (2) from
the A8A5 input attenuator.
Step 7. Referring to Figure 6-43, remove the 2 screws (4) from the assembly bracket.
Step 8. Remove the A8A5 assembly.
Figure 6-43
Input Attenuator Hardware
1
3
2
Chapter 6
207
Replacing Assemblies
A8 Sub-assemblies
Replacement
CAUTION
Use care not to pinch any cables during reassembly.
Step 1. Replace the A8A5 assembly.
Step 2. Referring to Figure 6-43, align the A8A5 assembly with the screw holes on the
assembly bracket, and replace the 2 screws (3). Tighten them to 9 inch-pounds.
Step 3. Refer to Figure 6-43. Reconnect the 2 semi-rigid cables W12 and W13 (2) to the
A8A5 attenuator. Torque to 5 inch-pounds.
Step 4. Refer to Figure 6-43. Reconnect the ribbon cable W5 (1) to the A8A5 attenuator.
Step 5. On models N8974A and N8975A, replace the A8A6 YIG-Tuned filter/mixer
assembly. Refer to the replacement procedure “A8A6 YIG-Tuned Filter/Mixer” on
page 204.
Step 6. On models N8974A and N8975A, replace the A8A4 LO amplifier and IF switch
(LOIS) assembly. Refer to the replacement procedure “A8A4 LO Amp/IF Switch
Assembly” on page 203.
Step 7. Replace the instrument chassis cover. Refer to the replacement procedure “Chassis
Cover” on page 153.
Step 8. Replace the A1 front frame assembly. Refer to the replacement procedure “A1
Front Frame Assembly” on page 155.
Step 9. On models N8974A and N8975A, align the YTF using the procedure described in
“Align YTF” on page 21.
Step 10. Refer to Chapter 7, “Post-Repair Procedures,” for further information on the
calibration and performance verification tests required after the assembly has been
replaced.
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Chapter 6
Replacing Assemblies
A8 Sub-assemblies
A8A2 Second Converter
CAUTION
Use ESD precautions when performing this replacement procedure.
Removal
Step 1. Remove the instrument chassis cover. Refer to the removal procedure “Chassis
Cover” on page 153.
Step 2. Remove the A1 front frame assembly. Refer to the removal procedure “A1 Front
Frame Assembly” on page 155.
Step 3. On models N8974A and N8975A, remove the A8A4 LO amplifier and IF switch
(LOIS) assembly. Refer to the removal procedure “A8A4 LO Amp/IF Switch
Assembly” on page 203.
Step 4. On models N8974A and N8975A, remove the A8A6 YIG-Tuned filter/mixer
assembly. Refer to the removal procedure “A8A6 YIG-Tuned Filter/Mixer” on
page 204.
Step 5. Remove the A8A5 input attenuator assembly. Refer to the removal procedure
“A8A5 Input Attenuator” on page 207.
Step 6. Refer to Figure 6-44, remove the 4 screws (1) from the assembly bracket and
remove the bracket.
Figure 6-44
Position of Screws Securing Assembly Bracket
1
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4 places
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Replacing Assemblies
A8 Sub-assemblies
Step 7. Refer to Figure 6-45 viewing the bottom side of the NFA, disconnect the flexible
coaxial cable W10 (1) from the A8A2 J4 connector.
Figure 6-45
Second Converter, Bottom View
1
Step 8. Refer to Figure 6-46. Disconnect the ribbon cable W5 (1) from the A8A2 second
converter.
Figure 6-46
Second Converter Hardware
1
2
3
5
5
3 places
4
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A8 Sub-assemblies
Step 9. Refer to Figure 6-46. Disconnect the semi-rigid cable W9 (2) from the A8A2 J1
connector.
Step 10. Refer to Figure 6-46. Disconnect the flexible coaxial cable W11 (3) from the
A8A2 J2 connector.
Step 11. On models N8974A and N8975A and referring to Figure 6-46. Disconnect the
SMA connector W21 (4) from the A8A2 J3 connector.
Step 12. Referring to Figure 6-46, remove the 3 screws (5) from the assembly bracket.
Step 13. Remove the A8A2 second converter assembly.
Replacement
Step 1. Refer to Figure 6-46. Install the second converter assembly with a single screw
(5), but do not fully tighten.
NOTE
The screws that secure the second converter in place are longer than the other
assembly screws.
Step 2. Install the other 2 screws (5), and tighten all 3 screws to 9 inch-pounds.
Step 3. On models N8974A and N8975A and referring to Figure 6-46. Reconnect the
SMA connector W21 (4) to the A8A2 J3 connector.
Step 4. Refer to Figure 6-46. Reconnect the flexible coaxial cable W11 (3) to the A8A2
J2 connector.
Step 5. Refer to Figure 6-46. Reconnect the semi-rigid cable W9 (2) to the A8A2 J1
connector. Torque to 5 inch-pounds.
Step 6. Refer to Figure 6-46. Reconnect the ribbon cable W5 (1) to the A8A2 second
converter.
Step 7. Refer to Figure 6-45 viewing the bottom side of the NFA, reconnect the flexible
coaxial cable W10 (1) to the A8A2 J4 connector.
Step 8. Refer to Figure 6-44. Replace the sub-bracket to the microcircuit bracket and
replace the 4 screws (1) to secure the assembly bracket. Tighten them to 9
inch-pounds.
Step 9. Replace the A8A5 attenuator assembly. Refer to the replacement procedure “A8A5
Input Attenuator” on page 207.
Step 10. On models N8974A and N8975A, replace the A8A6 YIG-Tuned filter/mixer
assembly. Refer to the replacement procedure “A8A6 YIG-Tuned Filter/Mixer” on
page 204.
Step 11. On models N8974A and N8975A, replace the A8A4 LO amplifier and IF switch
(LOIS) assembly. Refer to the replacement procedure “A8A4 LO Amp/IF Switch
Assembly” on page 203.
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Replacing Assemblies
A8 Sub-assemblies
Step 12. Replace the A1 front frame assembly. Refer to the replacement procedure “A1
Front Frame Assembly” on page 155.
Step 13. Replace the instrument chassis cover. Refer to the replacement procedure “Chassis
Cover” on page 153.
Step 14. On models N8974A and N8975A, align the YTF using the procedure described in
“Align YTF” on page 21.
Step 15. Refer to Chapter 7, “Post-Repair Procedures,” for further information on the
calibration and performance verification tests required after the assembly has been
replaced.
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Replacing Assemblies
A8 Sub-assemblies
Input Connector
CAUTION
Use ESD precautions when performing this replacement procedure.
Removal
Step 1. Remove the instrument chassis cover. Refer to the removal procedure “Chassis
Cover” on page 153.
Step 2. Remove the A1 front frame assembly. Refer to the removal procedure “A1 Front
Frame Assembly” on page 155.
Step 3. Remove the RF connector. For a Type-N connector, refer to the removal procedure
“Type-N Connector” on page 213. For a APC 3.5, refer to the removal procedure
“APC 3.5 Connector” on page 214.
Figure 6-47
RF Connector, Type-N and APC 3.5
Type-N Connector
(N8972A and N8973A)
1. Refer to Figure 6-47. Gently twist the water seal (1) and remove it from
around the input connector. Make sure the O-ring (2) is retained within the
water seal.
2. Use a 5/16” wrench to remove the semi-rigid (6) cable from the input
connector.
3. Loosen the nut (5) from the back side of the input connector with a 9/16”
wrench, and gently remove the connector, retaining the washer (4) and nut.
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Replacing Assemblies
A8 Sub-assemblies
APC 3.5 Connector
(N8974A and N8975A)
1. Refer to Figure 6-47. Use a 5/16” wrench to remove the semi-rigid (6) cable
from the input connector.
2. Remove the 2 screws that fasten the APC 3.5 connector assembly (3) to the
frame.
3. Remove the connector assembly.
Replacement
Step 1. Install the RF connector. For a Type-N connector, refer to the replacement
procedure “Type-N Connector” on page 213. For a APC 3.5, refer to the
replacement procedure “APC 3.5 Connector” on page 214.
Type-N Connector
1. Refer to Figure 6-47. Reattach the input connector and secure with the
washer(5), and nut(4). Tighten the nut to 21 inch-pounds.
2. Reattach the semi-rigid cable (6) to the input connector with a 5/16” wrench.
Tighten it to 10 inch-pounds.
3. Make sure the O-ring (2) is still inside the water seal (1), then gently twist
and push the water seal onto the input connector.
4. Continue with step 2 below.
APC 3.5 Connector
1. Refer to Figure 6-47. Reattach the APC 3.5 input connector assembly (2) and
secure with the 2 screws. Tighten them to 9 inch-pounds.
2. Reattach the semi-rigid cable (6) to the input connector with a 5/16” wrench.
Tighten it to 10 inch-pounds.
3. Continue with step 2 below.
Step 2. Reconnect the A1 front frame to the chassis. Refer to the replacement procedure
“A1 Front Frame Assembly” on page 155.
Step 3. Replace the chassis cover. Refer to the replacement procedure “Chassis Cover” on
page 153.
Step 4. Replace the outer case. Refer to the replacement procedure “Instrument Outer
Case” on page 149.
Step 5. Refer to Chapter 7, “Post-Repair Procedures,” for further information on the
calibration and performance verification tests required after the assembly has been
replaced.
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7
Post-Repair Procedures
Chapter 7
215
Post-Repair Procedures
What You Will Find in This Chapter
What You Will Find in This Chapter
The post repair and calibration and performance verification tests in this chapter
must be performed if there is an assembly has been replaced. The 10.0 MHz
adjustment should be performed if the NFA fails the 10.0 MHz performance test.
NOTE
Familiarize yourself with the safety symbols marked on the noise figure analyzer
and read the general safety considerations and the safety note definitions in the
front of this guide, before you begin the procedures in this chapter.
There is also an overview of the N2716A Performance Software.
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Chapter 7
Post-Repair Procedures
Before You Start
Before You Start
There are three things you should do before starting the post-repair procedures and
the calibration and performance verification procedure:
•
Check that you are familiar with the safety symbols marked on the noise figure
analyzer and read the general safety considerations and the symbol definitions
given in the front of this service guide.
•
Check that the noise figure analyzer has been turned on and allowed to warm
up for at least 30 minutes at room temperature before making any performance
verification. The noise figure analyzer must be allowed to stand at room
temperature at least 2 hours prior to the 30 minute warm-up.
•
Read the rest of this section.
Post-Repair Procedure
Step 1. Power up the repaired NFA.
Step 2. Check it passes the self-test. See “Bootrom Self-Test Check” on page 24.
Step 3. Ensure there are no error messages annotated in the display status line.
Step 4. Check there are no errors in the error queue, as shown in Figure 7-1.
Figure 7-1
Example of an Error Queue without any Errors Displayed
Step 5. Set the instrument to its Full Span. (This menu key is found under the Frequency
key.)
Chapter 7
217
Post-Repair Procedures
Before You Start
Step 6. Enter the noise source ENR Table data.
Step 7. Connect the Noise Source to the Input.
Step 8. Calibrate the NFA across the Full Span.
Step 9. If it performs the post-repair procedures correctly then run all the calibration and
performance verification checks located in the Calibration and Performance
Verification Guide for your noise figure analyzer or use the N2716A Performance
Verification Software. The tests are listed in the “Performance Verification and
Adjustment Procedures” section.
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Chapter 7
Post-Repair Procedures
Performance Verification and Adjustment Procedures
Performance Verification and Adjustment Procedures
Performance Verification Procedures
The NFA performance verification consists of the tests shown in Table 7-1. You
must run all these tests to verify the instrument’s performance.
Table 7-1
List of Performance Verification Tests
Test no.
Performance Verification Test
1
10 MHz Out Frequency Reference Accuracy a
2
Input VSWR
3
Frequency Accuracy
4
Noise Source Supply Accuracy
5
Noise Figure Range & Accuracy
6
Gain Measurement Uncertainty
7
Instrument Noise Figure
8
Measurement Jitter
a. If the 10.0 MHz Out Frequency Reference Accuracy performance verification
test fails, perform the calibration adjustment listed in Table 7-2.
Adjustment Procedures
The 10.0 MHz Out Frequency Reference can be adjusted using the procedure
described in the Calibration and Performance Verification Guide.
Table 7-2
NOTE
Adjustment
Adjustment no.
Calibration Adjustments
1
10 MHz Out Frequency Reference Adjustment
No other user adjustment is possible.
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Post-Repair Procedures
Agilent N2716A Performance Verification Software
Agilent N2716A Performance Verification Software
This section provides a brief description of performance verification and a list of
the tests supported by the performance verification software.
NOTE
For additional information on Performance Verification tests, refer to the on-line
help on the Agilent N2716A Performance Verification Software or the N2716A
Getting Started Guide.
Test Environment
Agilent Test Management Environment is the new high performance, 32 bit,
component-based calibration platform from Agilent Technologies, Inc.
Agilent Test Management Environment can be expanded by purchasing test
packages to test additional Agilent instruments. Agilent Test Management
Environment reduces the cost of instrument maintenance by providing quick and
accurate automated tests—reducing instrument downtime—and providing a
“common look and feel”—reducing operator training.
Performance Verification Tests
Performance verification tests are tests designed to provide the highest level of
confidence that the instrument being tested conforms to published, factory-set
specifications. The tests are supplied in an automated test software package. The
automatic execution of the full set of performance tests will take between two and
three hours to complete. Performance tests are designed to test an instrument
operating within the operational temperature range defined by the instrument
specifications. Some repairs require a performance test to be run after the repair.
If the instrument is unable to pass any of the performance tests or adjustment tests,
further repairs are needed.
The Agilent N2716A Performance Verification Software is sold as a separate
product that compliments the Agilent NFA products. For ordering information get
in touch with your local Agilent sales and service office listed in “Contacting
Agilent Technologies, Inc.” on page 140.
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Chapter 7
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