Service Manual
For Agilent Model
6611C, 6612C, 6613C, 6614C
System DC Power Supply
For instruments with Serial Numbers:
Agilent 6611C: US37450101 and up
Agilent 6612C: US37460101 and up
Agilent 6613C: US37460101 and up
Agilent 6614C: US37460101 and up
Agilent Part No. 5962-8200
Microfiche No 5962-8201
Printed in U.S.A.
September, 2000
Warranty Information
CERTIFICATION
Agilent Technologies certifies that this product met its published specifications at time of shipment from the factory.
Agilent Technologies further certifies that its calibration measurements are traceable to the United States National
Bureau of Standards, to the extent allowed by the Bureau's calibration facility, and to the calibration facilities of other
International Standards Organization members.
WARRANTY
This Agilent Technologies hardware product is warranted against defects in material and workmanship for a period
of three years from date of delivery. Agilent Technologies software and firmware products, which are designated by
Agilent Technologies for use with a hardware product and when properly installed on that hardware product, are
warranted not to fail to execute their programming instructions due to defects in material and workmanship for a
period of 90 days from date of delivery. During the warranty period Agilent Technologies will, at its option, either
repair or replace products which prove to be defective. Agilent Technologies does not warrant that the operation for
the software firmware, or hardware shall be uninterrupted or error free.
For warranty service, with the exception of warranty options, this product must be returned to a service facility
designated by Agilent Technologies. Customer shall prepay shipping charges by (and shall pay all duty and taxes)
for products returned to Agilent Technologies. for warranty service. Except for products returned to Customer from
another country, Agilent Technologies shall pay for return of products to Customer.
Warranty services outside the country of initial purchase are included in Agilent Technologies’ product price, only if
Customer pays Agilent Technologies international prices (defined as destination local currency price, or U.S. or
Geneva Export price).
If Agilent Technologies is unable, within a reasonable time to repair or replace any product to condition as warranted,
the Customer shall be entitled to a refund of the purchase price upon return of the product to Agilent Technologies.
LIMITATION OF WARRANTY
The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by the
Customer, Customer-supplied software or interfacing, unauthorized modification or misuse, operation outside of the
environmental specifications for the product, or improper site preparation and 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 THE CUSTOMER'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.
ASSISTANCE
The above statements apply only to the standard product warranty. Warranty options, extended support contacts,
product maintenance agreements and customer assistance agreements are also available. Contact your nearest
Agilent Technologies Sales and Service office for further information on Agilent Technologies' full line of Support
Programs.
2
Safety Summary
The following general safety precautions must be observed during all phases of operation of this instrument. Failure to comply
with these precautions or with specific warnings elsewhere in this manual violates safety standards of design, manufacture, and
intended use of the instrument. Agilent Technologies assumes no liability for the customer's failure to comply with these
requirements.
WARNING
Servicing instructions are for use by service-trained personnel. To avoid dangerous electrical shock, do not perform any servicing
unless you are qualified to do so. Some procedures described in this manual are performed with power supplied to the instrument
while its protective covers are removed. If contacted, the energy available at many points may result in personal injury.
BEFORE APPLYING POWER.
Verify that the product is set to match the available line voltage, the correct line fuse is installed, and all safety precautions (see
following warnings) are taken. In addition, note the instrument's external markings described under "Safety Symbols"
GROUND THE INSTRUMENT.
Before switching on the instrument, the protective earth terminal of the instrument must be connected to the protective conductor
of the (mains) power cord. The mains plug shall be inserted only in an outlet socket that is provided with a protective earth
contact. This protective action must not be negated by the use of an extension cord (power cable) that is without a protective
conductor (grounding). Any interruption of the protective (grounding) conductor or disconnection of the protective earth
terminal will cause a potential shock hazard that could result in personal injury.
FUSES
Only fuses with the required rated current, voltage, and specified type (normal blow, time delay, etc.) should be used. Do not use
repaired fuses or short-circuited fuseholders. To do so could cause a shock or fire hazard.
KEEP AWAY FROM LIVE CIRCUITS.
Operating personnel must not remove instrument covers. Component replacement and internal adjustments must be made by
qualified service personnel. Do not replace components with power cable connected. Under certain conditions, dangerous
voltages may exist even with the power cable removed. To avoid injuries, always disconnect power, discharge circuits and
remove external voltage sources before touching components.
DO NOT SERVICE OR ADJUST ALONE.
Do not attempt internal service or adjustment unless another person, capable of rendering first aid and resuscitation, is present.
Any adjustment, maintenance, and repair of this instrument while it is opened and under voltage should be avoided as much as
possible. When this is unavoidable, such adjustment, maintenance, and repair should be carried out only by a skilled person who
is aware of the hazard involved.
DO NOT SUBSTITUTE PARTS OR MODIFY INSTRUMENT.
Because of the danger of introducing additional hazards, do not install substitute parts or perform any unauthorized modification
to the instrument. Return the instrument to an Agilent Technologies Sales and Service Office for service and repair to ensure that
safety features are maintained.
SAFETY SYMBOLS
Refer to the table on the following page
WARNING
The WARNING sign denotes a hazard. It calls attention to a procedure, practice, or the like, which, if not
correctly performed or adhered to, could result in personal injury. Do not proceed beyond a WARNING sign
until the indicated conditions are fully understood and met.
Caution
The CAUTION sign denotes a hazard. It calls attention to an operating procedure, or the like, which, if not
correctly performed or adhered to, could result in damage to or destruction of part or all of the product. Do
not proceed beyond a CAUTION sign until the indicated conditions are fully understood and met.
3
Safety Symbol Definitions
Symbol
Description
Direct current
Alternating current
Both direct and alternating current
Three-phase alternating current
Earth (ground) terminal
Protective earth (ground) terminal
Frame or chassis terminal
Terminal is at earth potential (Used for measurement and control circuits designed to be
operated with one terminal at earth potential.)
Terminal for Neutral conductor on permanently installed equipment
Terminal for Line conductor on permanently installed equipment
On (supply)
Off (supply)
Standby (supply)
Units with this symbol are not completely disconnected from ac mains when this switch
is off. To completely disconnect the unit from ac mains, either disconnect the power
cord or have a qualified electrician install an external switch.
In position of a bi-stable push control
Out position of a bi-stable push control
Caution, risk of electric shock
Caution, hot surface
Caution (refer to accompanying documents)
4
Notice
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.
This document contains proprietary information which is protected by copyright. All rights are reserved. No part of
this document may be photocopied, reproduced, or translated into another language without the prior written consent
of Agilent Technologies.
ã Copyright 1998, 2000 Agilent Technologies, Inc.
Printing History
The edition and current revision of this manual are indicated below. Reprints of this manual containing minor
corrections and updates may have the same printing date. Revised editions are identified by a new printing date. A
revised edition incorporates all new or corrected material since the previous printing date.
Changes to the manual occurring between revisions are covered by change sheets shipped with the manual. In some
cases, the manual change applies only to specific instruments. Instructions provided on the change sheet will indicate
if a particular change applies only to certain instruments.
Edition 1...............................................................June, 1998
Edition 2...............................................................September, 2000
Instrument Identification
The power supply is identified by a unique, two-part serial number, such as, US37450101. The items in this serial
number are explained as follows:
US37450101
The first two letters indicate the country of manufacture. US = United States.
The next four digits are the year and week of manufacture or last significant design change. Add
1960 to the first two digits to determine the year. For example, 37=1997. The third and fourth
digits specify the week of the year (45 = the forty-fifth week).
The last four digits (0101) are a unique sequential number assigned to each unit.
5
Table of Contents
Warranty Information
Safety Summary
Notice
Printing History
Instrument Identification
Table of Contents
INTRODUCTION
Organization
Safety Considerations
Related Documents
Revisions
Manual Revisions
Firmware Revisions
Electrostatic Discharge
VERIFICATION AND PERFORMANCE TESTS
Introduction
Test Equipment Required
Measurement Techniques
Setup for Most Tests
Electronic Load
Current-Monitoring Resistor
Operation Verification Tests
Performance Tests
Programming
Constant Voltage (CV) Tests
CV Setup
Voltage Programming and Readback Accuracy
CV Load Effect
CV Source Effect
CV Noise (PARD)
Transient Recovery Time
Constant Current (CC) Tests
CC Setup
Current Programming and Readback Accuracy
Current Sink (CC-) Operation
CC Load and Line Regulation
CC Load Effect
CC Source Effect
CC Noise (PARD)
Performance Test Equipment Form
Performance Test Record Form
TROUBLESHOOTING
Introduction
Test Equipment Required
Overall Troubleshooting
Flow Charts
Specific Troubleshooting Procedures
Power-on Self-test Failures
6
2
3
4
5
5
6
9
9
9
9
10
10
10
10
11
11
11
12
12
13
14
14
14
14
15
15
15
15
16
16
16
17
17
17
18
18
19
20
20
21
22
27
27
28
28
28
33
33
CV/CC Status Annunciators Troubleshooting
Bias and Reference Supplies
J307 Voltage Measurements
Manual Fan Speed Control
Disabling Protection Features
Post-repair Calibration
Inhibit Calibration Switch
Calibration Password
Initialization
ROM Upgrade
Identifying the Firmware
Upgrade Procedure
Disassembly Procedures
List of Required Tools
Cover, Removal and Replacement
A2 Interface Board, Removal and Replacement
Front Panel Assembly, Removal and Replacement
A3 Front Panel Board, Removal and Replacement
A1 Main Control Board
T1 Power Transformer, Removal and Replacement
Line Voltage Wiring
PRINCIPLES OF OPERATION
Introduction
I/O Interface Signals
A3 Front Panel Circuits
A2 Interface Circuits
Primary Interface
Secondary Interface
A1 Main Board Circuits
Power Circuits
Control Circuits
REPLACEABLE PARTS LIST
34
34
35
36
36
37
37
37
38
38
38
38
39
39
40
40
40
41
41
41
42
43
43
43
44
44
44
44
45
45
46
49
Introduction
49
DIAGRAMS
53
Introduction
53
INDEX
57
7
1
Introduction
Organization
This manual contains information for troubleshooting and repairing Agilent Models 6611C, 6612C, 6613C and
6614C System DC Power Supplies. Hereafter all models will be referred to as the dc power supply.
This manual is organized as follows:
Chapter 1
Organization
Chapter 2
Performance tests
Chapter 3
Troubleshooting procedures
Chapter 4
Principles of operation on a block-diagram level
Chapter 5
Replaceable parts
Chapter 6
Diagrams
Safety Considerations
WARNING:
Hazardous voltages exist within the dc power supply chassis.
This dc power supply; is a Safety Class I instrument, which means it has a protective earth terminal. This terminal
must be connected to earth ground through a power source equipped with a 3-wire, ground receptacle. Refer to the
"Safety Summary" page at the beginning of this manual for general safety information. Before operation or repair,
check the dc power supply and review this manual for safety warnings and instructions. Safety warnings for specific
procedures are located at appropriate places in the manual.
Related Documents
The following documents are shipped with your dc power supply:
a a User’s Guide, Agilent part number 5962-8194, containing installation, operating, and calibration information
a a Programming Guide, Agilent part number 5962-8198, containing detailed GPIB programming information.
9
1 - Introduction
Revisions
Manual Revisions
This manual was written for dc power supplies that have the same manufacturing dates (the first four digits) as those
listed on the title page and whose unique identification number (the last four digits) are equal to or higher than those
listed in the title page.
NOTE:
1) If the first four digits of the serial number of your unit are higher than those shown in the title
page, your unit was made after the publication of this manual and may have hardware or firmware
differences not covered in this manual. If they are significant to the operation and/or servicing of
the dc power supply, those differences are documented in one or more Manual Change sheets
included with this manual.
2) If the first four digits of the serial number of your unit are lower than those shown on the title
page, your unit was made before the publication of this manual and may be different from that
described here. Such differences, if any, will be covered in a backdating section in Chapter 6.
Firmware Revisions
You can obtain the firmware revision number by either reading the integrated circuit label, or query the dc power
supply using the GPIB *IDN?' query command (See Chapter 3, ROM Upgrade).
Electrostatic Discharge
CAUTION:
The dc power supply has components that can be damaged by ESD (electrostatic discharge).
Failure to observe standard antistatic practices can result in serious degradation of performance,
even when an actual failure does not occur.
When working on the dc power supply, observe all standard, antistatic work practices. These include, but are not
limited to:
a
Working at a static-free station such as a table covered with static-dissipative laminate or with a conductive
table mat (Agilent P/N 9300-0797, or equivalent).
a
Using a conductive wrist strap, such as Agilent P/N 9300-0969 or 9300-0970.
a
Grounding all metal equipment at the station to a single common ground.
a
Connecting low-impedance test equipment to static-sensitive components only when those
components have power applied to them.
a
Removing power from the dc power supply before removing or installing printed circuit boards.
10
2
Verification and Performance Tests
Introduction
This document contains test procedures to verify that the dc power supply is operating normally and is within
published specifications. There are three types of tests as follows:
Built-in Self Tests
These tests, run automatically when the power supply is turned on, check most
of the digital circuits and the programming and readback DACs.
Operation Verification
These tests verify that the power supply is probably operating normally but do
not check all of the specified operating parameters.
Performance Tests
These tests check that the supply meets all of the operating specifications as
listed in the User’s Guide.
NOTE:
The dc power supply must pass the built-in self-tests before calibration or any of the verification
or performance tests can be performed. If the supply fails any of the tests or if abnormal test results
are obtained, refer to the troubleshooting procedures in Chapter 3. The troubleshooting procedures
will determine if repair and/or calibration is required.
Test Equipment Required
Table 2-1 lists the equipment required to perform the verification and performance tests. A test record sheet with
specification limits and measurement uncertainties (when test using the recommended test equipment) may be found
at the back of this section.
WARNING:
SHOCK HAZARD. These tests should only be performed by qualified personnel. During the
performance of these tests, hazardous voltages may be present at the output of the supply.
11
2 - Verification and Performance Tests
Table 2-1. Test Equipment Required for Verification and Performance Tests
Type
Specifications
Recommended Model
Current Monitor Resistor
15 A (0.1 ohm) 0.04%
Guildline 9230/15
DC Power Supply
Minimum 5 A output current rating
Agilent 6632B
Digital Voltmeter
Resolution: 10 nV @ 1V
Readout: 8 1/2 digits
Accuracy: 20 ppm
Agilent 3458A or equivalent
Electronic Load
100V, 5 A minimum, with transient capability
Agilent 6060B (60V max.), 6063B
(240V) or equivalent
GPIB Controller
Controller with full GPIB capabilities
HP Series 300 or equivalent
Resistors
400 ohm, 5W
Agilent p/n 0811-1857
1 ohm, 100 W (or 2 ohm adjustable)
Ohmite D12K2R0 (2 ohm adjustable)
(Load resistors may
substitute for electronic
load if load is too noisy
for CC PARD test)
0.6 ohm, 100W (6611C)
9 ohm, 100W (6612C)
49 ohm, 100W (6613C)
99 ohm, 100W (6614C)
or an appropriate 150W Rheostat
Oscilloscope
Sensitivity: 1 mV
Bandwidth Limit: 20 MHz
Probe: 1:1 with RF tip
Agilent 54504A or equivalent
RMS Voltmeter
True RMS
Bandwidth: 20 MHz
Sensitivity: 100 µV
Agilent 3400B or equivalent
Variable-Voltage
Transformer
Adjustable to highest rated input voltage
range.
Power: 500 VA
Measurement Techniques
Test Setup
All tests are performed at the rear terminals of the supply as shown in Figure 2-1. Measure the dc voltage directly at
the +S and -S terminals. Set the Remote/Local switch to Remote and connect the output for remote sensing. Use
adequate wire gauge for the load leads.
12
Verification and Performance Tests - 2
-S
-
+
SENSE
+S
-S
-
+
+S
Remote
Remote
NOTE: Connector
SENSE
Local
Local
is removable
+
-
+
-
50VDC MAX TO
Set to
Remote
Remote
-
-
DVM, Scope, or
DC
RMS voltmeter
(for CV tests)
DVM or
50VDC MAX TO
Set to
Load
resistor
400 ohm
Ampmeter
+
+
B.
Current
monitor
RMS voltmeter
-S
-
+
+S
SENSE
Local
(for CC tests)
+
Remote
+
-
-
50VDC MAX TO
Set to
+
Remote
Electronic
-
Load
DC
(see note)
Load
resistor
Ampmeter
400 ohm
+
Note: Use dc supply with same polarity
+
-
connectons for - CC tests.
Replace electronic load with resistors
External
for CC noise test.
DC supply
C.
A.
Figure 2-1. Test Setup
Electronic Load
Many of the test procedures require the use of a variable load capable of dissipating the required power. If a variable
resistor is used, switches should be used to either; connect, disconnect, or short the load resistor. For most tests, an
electronic load can be used. The electronic load is considerably easier to use than load resistors, but it may not be
fast enough to test transient recovery time and may be too noisy for the noise (PARD) tests.
Fixed load resistors may be used in place of a variable load, with minor changes to the test procedures. Also, if
computer controlled test setups are used, the relatively slow (compared to computers and system voltmeters) settling
times and slew rates of the power supply may have to be taken into account. "Wait" statements can be used in the test
program if the test system is faster than the supply.
13
2 - Verification and Performance Tests
Current-Monitoring Resistor
To eliminate output-current measurement error caused by voltage drops in the leads and connections, connect the
current monitoring resistor between the -OUT and the load as a four-terminal device. Connect the current-monitoring
leads inside the load-lead connections directly at the monitoring points on the resistor element.
Operation Verification Tests
To assure that the supply is operating properly, without testing all specified parameters, perform the turn-on and
checkout procedures given in the User’s Guide.
Performance Tests
NOTE:
A full Performance Test consists of only those items listed as “Specifications” in Table A-1 of the
User’s Guide, and that have a procedure in this document.
The following paragraphs provide test procedures for verifying the supply's compliance with the specifications listed
in Table A-1 of the User’s Guide. All of the performance test specifications and calculated measurement
uncertainties are entered in the appropriate Performance Test Record Card for your specific model. You can record
the actual measured values in the column provided in this card.
If you use equipment other than that recommended in Table 2-1, you must recalculate the measurement uncertainties
for the actual equipment used.
Programming
You can program the supply from the front panel keyboard or from a GPIB controller when performing the tests. The
test procedures are written assuming that you know how to program the supply either; remotely from a GPIB
controller or locally using the control keys and indicators on the supply's front panel. Complete instructions on
remote and local programming are given in the User’s Guide and in the Programming Guide.
Table 2-2. Programming and Output Values
Model
6611C
6612C
6613C
6614C
14
Full scale
Voltage
8
20
50
100
Vmax
8.190
20.475
51.187
102.38
Full Scale
Current
5
2
1
0.5
Imax
Isink
OV Max
5.1187
2.0475
1.0238
0.5118
-3A
- 1.2 A
- 0.6 A
- 0.3 A
8.8
22
55
110
Verification and Performance Tests - 2
Constant Voltage (CV) Tests
CV Setup
If more than one meter or if a meter and an oscilloscope are used, connect each to the terminals by a separate pair of
leads to avoid mutual coupling effects. For constant voltage dc tests, connect only to +S and -S, since the unit
regulates the output voltage that appears between +S and -S, and not between the (+) and (-) output terminals. Use
coaxial cable or shielded two-wire cable to avoid noise pickup on the test leads.
Voltage Programming and Readback Accuracy
This test verifies that the voltage programming, GPIB readback and front panel display functions are within
specifications. Note that the values read back over the GPIB should be identical to those displayed on the front
panel.
a.
Turn off the supply and connect a digital voltmeter between the +S and the -S terminals as shown in Figure 2-1a.
b.
Turn on the supply and program the supply to zero volts and the maximum programmable current (Imax in
Table 2-2) with the load off.
c.
Record the output voltage readings on the digital voltmeter (DVM) and the front panel display. The readings
should be within the limits specified in the performance test record card for the appropriate model under Voltage
Programming and Readback @ 0 Volts. Also, note that the CV annunciator is on. The output current reading
should be approximately zero.
d.
Program the output voltage to full-scale (See Table 2-2) .
e.
Record the output voltage readings on the DVM and the front panel display. The readings should be within the
limits specified in the performance test record card for the appropriate model under Voltage Programming and
Readback @ Full Scale.
CV Load Effect
This test measures the change in output voltage resulting from a change in output current from full load to no load.
a.
Turn off the supply and connect the output as shown in Figure 2-1a with the DVM connected between the +S
and -S terminals.
b.
Turn on the supply and program the current to the maximum programmable value (Imax) and the voltage to the
full-scale value in Table 2-2.
c.
Adjust the load for the full-scale current in Table 2-2 as indicated on the front panel display. The CV
annunciator on the front panel must be on. If it is not, adjust the load so that the output current drops slightly.
d.
Record the output voltage reading on the DVM connected to +S and -S.
e. Open the load and again record the DVM voltage reading. The difference between the DVM readings
in steps (d) and (e) is the load effect voltage, and should not exceed the value listed in the
performance test record card for the appropriate model under CV Load Effect.
15
2 - Verification and Performance Tests
CV Source Effect
This test measures the change in output voltage that results from a change in ac line voltage from the minimum to
maximum value within the line voltage specifications.
a.
Turn off the supply and connect the ac power line through a variable voltage transformer.
b.
Connect the output as shown in Figure 2-1a with the DVM connected between the +S and the -S terminals. Set
the transformer to nominal line voltage.
c.
Turn on the supply and program the current to the maximum programmable value (Imax) and the output voltage
to the full-scale value in Table 2-2.
d.
Adjust the load for the full-scale current value in Table 2-2 as indicated on the front panel display. The CV
annunciator on the front panel must be on. If it is not, adjust the load so that the output current drops slightly.
e.
Adjust the transformer to the lowest rated line voltage (e.g., 104 Vac for a 115 Vac nominal line voltage input).
f.
Record the output voltage reading on the DVM.
g.
Adjust the transformer to the highest rated line voltage (e.g., 127 Vac for 115 Vac nominal line voltage input).
h.
Record the output voltage reading on the DVM. The difference between the DVM reading is steps (f) and (h) is
the source effect voltage and should not exceed the value listed in the performance test record card for the
appropriate model under CV Source Effect.
CV Noise (PARD)
Periodic and random deviations (PARD) in the output (ripple and noise) combine to produce a residual ac voltage
superimposed on the dc output voltage. CV PARD is specified as the rms or peak-to-peak output voltage in the
frequency range specified in the User’s Guide.
a.
Turn off the supply and connect the output as shown in Figure 2-1a to an oscilloscope (ac coupled) between the
(+) and the (-) terminals. Set the oscilloscope's bandwidth limit to 20 MHz and use an RF tip on the oscilloscope
probe.
b.
Turn on the supply and program the current to the maximum programmable value (Imax) and the output voltage
to the full-scale value in Table 2-2.
c.
Adjust the load for the full-scale current value in Table –2 as indicated on the front panel display.
d.
Note that the waveform on the oscilloscope should not exceed the peak-to-peak limits in the performance test
record card for the appropriate model under CV Noise (PARD).
e.
Disconnect the oscilloscope and connect an ac rms voltmeter in its place. The rms voltage reading should not
exceed the RMS limits in the performance test record card for the appropriate model under CV Noise (PARD).
Transient Recovery Time
This test measures the time for the output voltage to recover to within the specified value following a 50% change in
the load current.
16
Verification and Performance Tests - 2
Loading
Transient
tttt
t
v
t
v
Unloading
Transient
Figure 2-2. Transient Waveform
a.
Turn off the supply and connect the output as in Figure 2-1a with the oscilloscope across the +S and -S
terminals.
b.
Turn on the supply and program the output current to the maximum programmable value (Imax) and the voltage
to the full-scale value in Table 2-2.
c.
Set the load to the Constant Current mode and program the load current to 1/2 the power supply full-scale rated
current.
d.
Set the electronic load's transient generator frequency to 100 Hz and its duty cycle to 50%.
e.
Program the load's transient current level to the supply's full-scale current value and turn the transient generator
on.
f.
Adjust the oscilloscope for a waveform similar to that in Figure 2-2.
g.
The output voltage should return to within the specified voltage (v) in less than 100uS (t). Check both loading
and unloading transients by triggering on the positive and negative slope. Record the voltage at time “t” in the
performance test record card under CV Transient Response.
Constant Current (CC) Tests
CC Setup
Follow the general setup instructions in the Measurement Techniques paragraph and the specific instructions given in
the following paragraphs.
Current Programming and Readback Accuracy
This test verifies that the current programming and readback are within specification.
a.
Turn off the supply and connect the current monitoring resistor across the power supply output and the DVM
across the resistor. See "Current Monitoring Resistor" for connection information.
b.
Turn on the supply and program the output voltage to 5 V and the current to zero amps. The power supply’s
current detector must be set to DC and the programming language mode to SCPI. See the specifications for high
range current readback in the User’s Guide if operating with the detector in ACDC or the language in
Compatibility mode.
17
2 - Verification and Performance Tests
c.
Divide the voltage drop (DVM reading) across the current monitoring resistor by its resistance to convert to
amps and record this value (Iout). Also, record the current reading on the front panel display. The readings
should be within the limits specified in the performance test record card for the appropriate model under Current
Programming and Readback @ 0 Amps.
d.
Program the output current to the full-scale value in Table 2-2.
e.
Divide the voltage drop (DVM reading) across the current monitoring resistor by its resistance to convert to
amps and record this value (Iout). Also, record the current reading that appears on the front panel display. The
readings should be within the limits specified in the performance test record card for the appropriate model
under Current Programming and Readback @ Full Scale.
Current Sink (-CC) Operation
This test verifies current sink operation and readback.
a.
Turn off the supply and connect the output as shown in Figure 2-1a, except connect a dc power supply in place
of the electronic load as indicated. Set the DMM to operate in voltage mode.
b.
Set the external power supply to 5 V and the current to the full scale current rating of the supply under test as in
Table 2-2.
c.
Turn on the supply under test and program the output voltage to zero and the current to full scale as in Table 22. The current on the UUT display should be negative and approximately 60% of the current rating.
d.
Divide the voltage drop across the current monitoring resistor by its resistance to obtain the current sink value in
amps and subtract this from the current reading on the display. The difference between the readings should be
within the limits specified in the performance test record card under Current Sink Readback.
Low Range Current Readback Accuracy
This test verifies the readback accuracy of the 20 milliampere current range.
a.
Turn off the supply and connect the output as shown in Figure 2-1b. Set the DMM to operate in current mode.
b.
Turn on the supply under test and set the current range readback to Low or Auto. Program the output voltage to
zero and the current to the full scale value in Table 2-2. The current on the UUT display should be
approximately 0 mA.
c.
Record the current reading on the DMM and the reading on the front panel display. The difference between the
two readings should be within the limits specified in the performance test record card under 20mA Range
Current Readback Accuracy @ 0A.
d.
Program the output voltage to 8V and record the current reading on the DMM and the reading on the front
panel display. If the meter indicates overrange, lower the 8 volts slightly. The difference between the readings
should be within the limits specified in the performance test record card for the appropriate model under 20mA
Range Current Readback Accuracy @ +20mA
e.
Turn off the supply and connect the output and an external supply as shown in Figure 2-1c. Set the DMM to
operate in current mode.
f.
Turn on the external supply and program it to 8V and 1 amp. Then program the supply under test to zero volts
and 1 amp. If the meter indicates overrange, lower the voltage of the external supply slightly. The UUT display
should read approximately −20 mA.
g.
Record the current reading on the DMM and the reading on the front panel display. The difference between the
two readings should be within the limits specified in the performance test record card under 20mA Range
Current Readback Accuracy @ −20 mA.
18
Verification and Performance Tests - 2
CC Load and Line Regulation
These tests (CC Load Effect and CC Source Effect given below) are tests of the dc regulation of the power supply's
output current. To insure that the values read are not the instantaneous measurement of the ac peaks of the output
current ripple, several dc measurements should be made and the average of these readings calculated. An example of
how to do this is given below using an Agilent 3458A System Voltmeter programmed from the front panel. Set up
the voltmeter and execute the "Average Reading" program follows:
a.
Program 10 power line cycles per sample by pressing NPLC 1 0 ENTER .
b.
Program 100 samples per trigger by pressing (N Rdgs/Trig) 1 0 0 ENTER .
c.
Set up voltmeter to take measurements in the statistical mode as follows:
Press Shift key, f0, Shift key, N
Press ^ (up arrow) until MATH function is selected, then press >.
Press ^ (up arrow until STAT function is selected then press (ENTER).
d.
Set up voltmeter to read the average of the measurements as follows:
Press Shift key, f1, Shift key, N.
Press down arrow until RMATH function is selected, then press >.
Press ^ (up arrow) until MEAN function is selected, then press ENTER.
e.
Execute the program by pressing f0, ENTER, TRIG, ENTER
f.
Wait for 100 readings and then read the average measurement by pressing f1, ENTER.
To repeat the measurement, perform steps (e) and (f).
CC Load Effect
This test measures the change in output current for a change in load from full scale output voltage to short circuit.
a.
Turn off the supply and connect the output as shown in Figure 2-1a with the DVM connected across the current
monitoring resistor.
b.
Turn on the supply and if it was set to low range readback in the previous test, set it back to high or auto.
Program the current to full scale and the output voltage to the maximum programmable voltage value (Vmax) in
Table 2-2.
c.
Adjust the load in the CV mode for the UUT full scale voltage in Table 2-2 as indicated on the front panel
display. Check that the CC annunciator is on. If it is not, adjust the load so that the output voltage drops slightly.
d.
Record the output current reading (DVM reading/current monitor resistance value in ohms). You may want to
use the average reading program described under “CC Load and Line Regulation”.
e.
Short the load switch and record the output current reading. The difference in the current readings in steps (d)
and (e) is the load effect and should not exceed the limit specified in the performance test record card for the
appropriate model under CC Load Effect.
19
2 - Verification and Performance Tests
CC Source Effect
This test measures the change in output current that results when the AC line voltage changes from the minimum to
the maximum value within the specifications.
a.
Turn off the supply and connect the ac power line through a variable voltage transformer.
b.
Connect the output terminals as shown in Figure 2-1a with the DVM connected across the current monitoring
resistor. Set the transformer to the nominal line voltage.
c.
Turn on the supply and program the current to the full scale value and the output voltage to the maximum
programmable value (Vmax) in Table 2-2.
d.
Adjust the load in the CV mode for full scale voltage as indicated on the front panel display. Check that the CC
annunciator is on. If it is not, adjust the load so that the output voltage drops slightly.
e.
Adjust the transformer to the lowest rated line voltage.
f.
Record the output current reading (DVM reading/current monitoring resistor in ohms). You may want to use the
average reading program described under “CC Load and Line Regulation”.
g.
Adjust the transformer to the highest rated line voltage.
h.
Record the output current reading again. The difference in the current readings in steps (f) and (h) is the CC
source effect and should not exceed the values listed in the performance test record card under CC Source
Effect.
CC Noise (PARD)
Periodic and random deviations (PARD) in the output combine to produce a residual ac current, as well, as an ac
voltage superimposed on the dc output. Constant current (CC) PARD is specified as the rms output current in a
frequency range 20 Hz to 20 Mhz with the supply in CC operation.
a.
Turn off the supply and connect the load, monitoring resistor, and rms voltmeter as shown in Figure 2-1a. The
Current Monitoring resistor may have to be substituted by one with a higher resistance and power rating, such as
a 1 ohm 50W, to get the RMS voltage drop high enough to measure with the RMS voltmeter. Leads should be as
short as possible to reduce noise pick-up. An electronic load may contribute ripple to the measurement so if the
RMS noise is above the specification a resistive load may have to be substituted for this test.
b.
Check the test setup for noise with the supply turned off. Other equipment (e.g. computers, DVMs, etc.) may
affect the reading.
c.
Turn on the supply and program the current to full scale and the output voltage to the maximum programmable
value (Vmax) in Table 2-2.
d.
The output current should be at the full scale rating with the CC annunciator on.
e.
Divide the reading on the rms voltmeter by the load resistance to obtain rms current. It should not exceed the
values listed in the performance test record card under CC Noise (RMS).
20
Verification and Performance Tests - 2
Performance Test Equipment Form
Test Facility:_________________________
Report Number ________________________
____________________________________
Date _________________________________
____________________________________
Customer _____________________________
____________________________________
Tested By ____________________________
Model ______________________________
Ambient Temperature (C) ________________
Serial No. ____________________________
Relative Humidity (%) ___________________
Options _____________________________
Nominal Line Frequency __________________
Firmware Revision ____________________
Special Notes:
Test Equipment Used:
Description
Model No.
Trace No.
Cal. Due Date
AC Source
_________________
_________________
_________________
DC Voltmeter
_________________
_________________
_________________
RMS Voltmeter
_________________
_________________
_________________
Oscilloscope
_________________
_________________
_________________
Electronic Load
_________________
_________________
_________________
Current Shunt
_________________
_________________
_________________
_________________
_________________
_________________
21
2 - Verification and Performance Tests
Performance Test Record Form
Model Agilent 6611C
Test Description
Report No _______________ Date __________________
Minimum
Specs.
Results*
Maximum
Specs.
Measurement
Uncertainty
− 5 mV
__________
+ 5 mV
1.6 µV
Vout + 2 mV
1.6 µV
Constant Voltage Tests
Voltage Programming and Readback
Low Voltage (0V) Vout
Vout − 2 mV
__________
High Voltage (Full Scale) Vout
7.991 V
__________
8.009 V
335 µV
Front Panel Display Readback
Vout − 4.4mV
__________
Vout + 4.4 mV
335 µV
Load Effect
Vout − 2.0mV
__________
Vout + 2.0mV
20 µV
Source Effect
Vout − 0.5mV
__________
Vout + 0.5 mV
20 µV
Peak-to-Peak
Vout − 3 mV
__________
Vout + 3 mV
872 µV
RMS
Vout − 0.5mV
__________
Vout + 0.5 mV
50 µV
Vout − 20 mV
__________
Vout + 20 mV
3 mV
− 2.0 mA
__________
+ 2.0 mA
15.2 µA
Iout − 0.5 mA
__________
Iout + 0.5 mA
15.2 µA
4.9955 A
__________
5.0045 A
252 µA
Front Panel Display Readback
PARD (Ripple and Noise)
Transient Response
Time in 100 µs
Constant Current Tests
Current Programming and Readback
Low current (0A) Iout
Readback Accuracy @ Iout
High Current (Full Scale) Iout
Readback Accuracy @ Iout
Current Sink (@ -3A) Readback
Iout − 10.5mA __________ Iout + 10.5mA
252 µA
Iout − 7.1 mA
__________
Iout + 7.1 mA
200 µA
− 2.5 µA
__________
+ 2.5 µA
0.1 µA
20 mA Range Current Readback
Readback Accuracy @ 0 A
Readback Accuracy @ + 20 mA
Readback Accuracy @ − 20 mA
Iout − 22.5 µA __________ Iout + 22.5 µA
Iout − 22.5 µA __________ Iout + 22.5 µA
1.7 µA
1.7 µA
PARD (Current Ripple and Noise)
RMS
Load Effect
Source Effect
22
− 2.0 mA
__________
+ 2.0 mA
200 µA
− 1 mA
__________
+ 1 mA
1.6 µA
− 0.5 mA
__________
+ 0.5 mA
1.6 µA
Verification and Performance Tests - 2
Model 6612C
Test Description
Report No _______________ Date __________________
Minimum
Specs.
Results*
Maximum
Specs.
Measurement
Uncertainty
− 10 mV
__________
+ 10 mV
1.6 µV
Front Panel Display Readback
Vout − 3 mV
__________
Vout + 3 mV
1.6 µV
High Voltage (Full Scale) Vout
19.980 V
__________
20.020 V
335 µV
Front Panel Display Readback
Vout − 9 mV
__________
Vout + 9 mV
335 µV
Load Effect
Vout − 2.0 mV __________
Vout + 2.0mV
20 µV
Source Effect
Vout − 0.5 mV __________
Vout + 0.5 mV
20 µV
Vout + 3 mV
872 µV
Vout − 0.5 mV __________
Vout + 0.5 mV
50 µV
Vout − 20 mV
__________
Vout + 20 mV
3 mV
− 1.0 mA
__________
+ 1.0 mA
15.2 µA
Constant Voltage Tests
Voltage Programming and Readback
Low Voltage (0V) Vout
PARD (Ripple and Noise)
Peak-to-Peak
RMS
Vout − 3 mV
__________
Transient Response
Time in 100 µs
Constant Current Tests
Current Programming and Readback
Low current (0A) Iout
15.2 µA
High Current (Full Scale) Iout
Iout − 0.25 mA __________ Iout + 0.25 mA
__________
2.002 A
1.998 A
Readback Accuracy @ Iout
Readback Accuracy @ Iout
Current Sink (@ -1.2A) Readback
252 µA
Iout − 4.3 mA
__________
Iout + 4.3 mA
252 µA
Iout − 3.3 mA
__________
Iout + 3.3 mA
200 µA
− 2.5 µA
__________
+ 2.5 µA
0.1 µA
20 mA Range Current Readback
Readback Accuracy @ 0 A
Readback Accuracy @ + 20 mA
Readback Accuracy @ − 20 mA
Iout − 22.5 µA __________ Iout + 22.5 µA
Iout − 22.5 µA __________ Iout + 22.5 µA
1.7 µA
1.7 µA
PARD (Current Ripple and Noise)
− 1.0 mA
__________
+ 1.0 mA
200 µA
Load Effect
− 0.5 mA
__________
+ 0.5 mA
1.6 µA
Source Effect
− 0.5 mA
__________
+ 0.5 mA
1.6 µA
RMS
23
2 - Verification and Performance Tests
Model Agilent 6613C
Test Description
Report No _______________ Date __________________
Minimum
Specs.
Results*
Maximum
Specs.
Measurement
Uncertainty
− 20 mV
__________
+ 20 mV
1.6 µV
Front Panel Display Readback
Vout − 6 mV
__________
Vout + 6 mV
1.6 µV
High Voltage (Full Scale) Vout
49.955 V
__________
50.045 V
335 µV
Front Panel Display Readback
Vout − 21 mV
__________
Vout + 21 mV
335 µV
Load Effect
Vout − 4 mV
__________
Vout + 4 mV
20 µV
Source Effect
Vout − 1 mV
__________
Vout + 1 mV
20 µV
Peak-to-Peak
Vout − 4 mV
__________
Vout + 4 mV
872 µV
RMS
Vout − 0.5mV
__________
Vout + 0.5 mV
50 µV
Vout − 50 mV
__________
Vout + 50 mV
3 mV
− 0.5 mA
__________
+ 0.5 mA
15.2 µA
Iout − 0.2 mA
__________
Iout + 0.2 mA
15.2 µA
0.999 A
__________
1.001 A
252 µA
Iout − 2.2 mA
__________
Iout + 2.2 mA
252 µA
Iout − 2 mA
__________
Iout + 2 mA
200 µA
− 2.5 µA
__________
+ 2.5 µA
0.1 µA
Constant Voltage Tests
Voltage Programming and Readback
Low Voltage (0V) Vout
PARD (Ripple and Noise)
Transient Response
Time in 100 µs
Constant Current Tests
Current Programming and Readback
Low current (0A) Iout
Readback Accuracy @ Iout
High Current (Full Scale) Iout
Readback Accuracy @ Iout
Current Sink (@ -0.6A) Readback
20 mA Range Current Readback
Readback Accuracy @ 0 A
Readback Accuracy @ + 20 mA
Readback Accuracy @ − 20 mA
Iout − 22.5 µA __________ Iout + 22.5 µA
Iout − 22.5 µA __________ Iout + 22.5 µA
1.7 µA
1.7 µA
PARD (Current Ripple and Noise)
− 1.0 mA
__________
+ 1.0 mA
200 µA
Load Effect
− 0.5 mA
__________
+ 0.5 mA
1.6 µA
Source Effect
− 0.25mA
__________
+ 0.25mA
1.6 µA
RMS
24
Verification and Performance Tests - 2
Model Agilent 6614C
Test Description
Report No _______________ Date __________________
Minimum
Specs.
Results*
Maximum
Specs.
Measurement
Uncertainty
− 50 mV
__________
+ 50 mV
1.6 µV
Front Panel Display Readback
Vout − 12 mV
__________
Vout + 12 mV
1.6 µV
High Voltage (Full Scale) Vout
99.900 V
__________
100.100 V
335 µV
Front Panel Display Readback
Vout − 42 mV
__________
Vout + 42 mV
335 µV
Load Effect
Vout − 5 mV
__________
Vout + 5 mV
20 µV
Source Effect
Vout − 1 mV
__________
Vout + 1 mV
20 µV
Vout − 5 mV
__________
Vout + 5 mV
872 µV
Vout − 0.5 mV __________
Vout + 0.5 mV
50 µV
Vout − 100mV __________
Vout + 100mV
3 mV
Constant Voltage Tests
Voltage Programming and Readback
Low Voltage (0V) Vout
PARD (Ripple and Noise)
Peak-to-Peak
RMS
Transient Response
Time in 100 µs
Constant Current Tests
Current Programming and Readback
Low current (0A) Iout
Readback Accuracy @ Iout
High Current (Full Scale) Iout
Readback Accuracy @ Iout
Current Sink (@ -0.3A) Readback
− 0.25 mA
__________
+ 0.25 mA
15.2 µA
Iout − 0.1 mA
__________
Iout + 0.1 mA
15.2 µA
0.4995 A
__________
0.5005 A
252 µA
Iout − 1.1 mA
__________
Iout + 1.1 mA
252 µA
Iout − 1.3 mA
__________
Iout + 1.3 mA
200 µA
− 2.5 µA
__________
+ 2.5 µA
0.1 µA
20 mA Range Current Readback
Readback Accuracy @ 0 A
Readback Accuracy @ + 20 mA
Readback Accuracy @ − 20 mA
Iout − 22.5 µA __________ Iout + 22.5 µA
Iout − 22.5 µA __________ Iout + 22.5 µA
1.7 µA
1.7 µA
PARD (Current Ripple and Noise)
− 1.0 mA
__________
+ 1.0 mA
200 µA
Load Effect
− 0.5 mA
__________
+ 0.5 mA
1.6 µA
Source Effect
− 0.25mA
__________
+ 0.25mA
1.6 µA
RMS
* Enter your test results in this column
25
3
Troubleshooting
Introduction
WARNING:
SHOCK HAZARD. Most of the troubleshooting procedures given in this chapter are
performed with power applied and protective covers removed. Such maintenance should
be performed only by service trained personnel who are aware of the hazards (for
example, fire and electrical shock).
CAUTION:
This instrument uses components which can either be damaged or suffer serious
performance degradation as a result of ESD (electrostatic discharge). Observe the
standard antistatic precautions to avoid damage to the components. An ESD summary is
given in Chapter 1.
This chapter provides troubleshooting and repair information for the dc power supply. Before attempting to
troubleshoot the supply, first check that the problem is with the supply itself and not with an associated
circuit. The verification tests in Chapter 2 enable you to isolate a problem to the dc power supply.
Troubleshooting procedures are provided to isolate a problem to one of the circuit boards. Figure 3-2 shows
the location of the circuit boards and other major components of the unit. Disassembly procedures are
provided at the end of this chapter and should be referred to, as required, in order to gain access to and/or
replace defective components.
If an assembly is defective, replace it and then conduct the verification test given in Chapter 2.
NOTE:
Note that when either the A1 Control Board or the A2 Interface Board are replaced, the
supply must be calibrated (See "Post Repair Calibration" later in this chapter). If the A2
Interface Board is replaced, the supply must be initialized before it is calibrated. See
"Initialization" later in this chapter.
Chapter 5 lists all of the replaceable parts for the power supply. Chapter 6 contains block diagrams, test
point measurements, and component location diagrams to aid you in troubleshooting the supply.
27
3 - Troubleshooting
Test Equipment Required
Table 3-1 lists the test equipment required to troubleshoot the power supply. Recommended models are
listed.
Table 3-1. Test Equipment Required for Troubleshooting
Type
Purpose
Recommended Model
GPIB Controller
To communicate with the supply via the
GPIB interface
HP Series 200/300
Digital Voltmeter
To check various voltage levels
Agilent 3458A
Oscilloscope
To check waveforms and signal levels
Agilent 54504A/54111A
Electronic Load
To test operation of current circuit
Agilent 6060B (60V) or 6063B
(240V)
Ammeter/Current
Shunt
To measure output current
Guildline 9230/15
Overall Troubleshooting
Overall troubleshooting procedures for the power supply are given in the Figure 3-1. The procedures first
check that neither an AC input, nor a bias supply failure is causing the problem and that the supply passes
the turn-on self test (error annunciator stays off). The normal turn-on, self-test indications are described in
the "Checkout Procedure" in Chapter 3 of the User's Guide.
If the supply passes the self test and there are no obvious faults, you should perform the verification
procedures in Chapter 2 from the front panel to determine if any functions are not calibrated or are not
operating properly. Then program and read back a voltage via the GPIB to see if the supply responds
properly to bus commands. If the supply fails any of the tests, you will be directed to the applicable flow
chart or troubleshooting procedure.
Flow Charts
Troubleshooting flow charts are given in Figure 3-1 sheets 1-4. The flow charts make reference to the test
points listed in Chapter 6. The circuit locations of the test points are shown on the component location
diagrams in Chapter 6.
28
Troubleshooting - 3
Turn on unit and observe the
display. All of the segments and
annunciators, the address and
then after self test should display
an error message or go to the
metering mode.
Check Bias voltages
(see Table 3-3)
Bias voltages OK?
No
Transformer Inputs
OK?
No
Check Main Fuse,
Replace T1
Yes
Yes
Replace A1
Display comes on?
+5V @ A2J211-1 (to
chassis)?
No
No
Check A1F305,
Red/White/Black
cable A1-A2 &
cable A2-A3, track
on A2 (J206-J211)
Yes
Yes
Error Message?
Yes
Go to Error Message
Table 3-2.
A3J111-5 low (no
pulses)?
No
Replace A3
No
Yes
Protect
annunciator
on?
Yes
RI?
Yes
Replace A2
No
OV?
Yes
Check for OV setting <
Voltage setting, Replace
A1
Yes
Check that OCP is not
enabled, Replace A1
Yes
Check F309 (fuse near
main heat sink),
Replace A1
No
No
OC?
No
FS?
No
Go to Sheet 2
For OT check fan,
Replace A1
Figure 3-1 Sheet 1. Troubleshooting Flowchart
29
3 - Troubleshooting
From Sheet 1
Enable output and
program voltage and
current full scale with no
load. Measure output
voltage.
Unit OV's?
Check to insure OV
setting is not less than
Yes
the voltage setting. If not
then replace A1.
No
Output voltage
> 10% error?
Yes
CV_Prog &
CC_Prog OK? (see
Table 3-4)
Yes
Check cable W9,
Replace A1
No
No
Replace A2
Output out of spec
but close?
Yes
Calibrate voltage
No
Output OK but
meter wrong?
Yes
Calibrate voltage. If
still wrong or will not
calibrate, replace A2
No
Program the OV 2
volts lower than the
output voltage.
Unit OV's?
Yes
Go to Sheet 3
No
Program OV to
full scale
OV_Prog OK?
(see Table 3-4)
Yes
No
Replace A2
Figure 3-1 Sheet 2. Troubleshooting Flowchart
30
Calibrate OV. If OV is still
not functioning properly
check W9, replace A1.
Troubleshooting - 3
From Sheet 2
Program current to full
scale, voltage to Vmax
and load to the power
supply's rated current.
Supply should be in CC.
Will not go into CC
or error > 10%
?
Yes
CC_Prog OK ?
(see Table 3-4)
Yes
Replace A1
No
No
Replace A2
Output out of spec
but close?
Yes
Calibrate unit
No
Output OK but
meter wrong?
Yes
Calibrate current. If still
wrong or will not
calibrate, replace A2
No
Turn on OCP and
insure Protect trips.
Prot trips?
No
CC_detect* low?
(see Table 3-4)
No
Check cable W9,
replace A1
Yes
Yes
Replace A2
Goto Sheet 4
Figure 3-1 Sheet 3. Troubleshooting Flowchart
31
3 - Troubleshooting
From Sheet 3
Connect controller to the
HPIB port and send
commands to set the
output voltage and
current and readback the
output.
Accepts and reads
back?
No
Replace A2
Yes
Run the Performance
Test in Chapter 2.
Passes test?
No
Regulation, Transient
Response and ripple
problems are generally
caused by A1
Yes
Short RI terminals on
rear of supply and insure
output disables and Prot
annunciator comes on.
Remote Inhibit
OK?
No
Replace A2
Yes
There is either no fault
with the power supply or
the problem is not
covered by this
procedure.
Figure 3-1 Sheet 4. Troubleshooting Flowchart
32
Troubleshooting - 3
Specific Troubleshooting Procedures
Power-on Self-test Failures
The power-on self-test sequence tests most of the digital and DAC circuits. If the supply fails self-test, the
display "ERR" annunciator will come on. You can then query the unit to find out what the error(s) are.
When an error is detected, the output is not disabled so you can still attempt to program the supply to help
troubleshoot the unit. Table 3-2 lists the self test errors and gives the probable cause for each error.
NOTE:
A partial self test is performed when the *TST? query is executed. Those tests that
interfere with normal interface operation or cause the output to change are not performed
by *TST?. The return value of *TST? will be zero if all tests pass, or the error code of the
first test that failed. The power supply will continue normal operation if *TST? returns a
non-zero value.
Table 3-2. Self-Test Error Codes/Messages
Error Code
Description
Probable Cause
E1
Checksum in Read-only Non-volatile ROM
A2 Interface Bd
E2
Checksum in Config Non-volatile ROM
A2 Interface Bd
E3
Checksum in Cal Non-volatile ROM
A2 Interface Bd
E4
Checksum in State Non-volatile ROM
A2 Interface Bd
E5
Checksum in RST Non-volatile ROM
A2 Interface Bd
E10
RAM test failed
A2 Interface Bd
E11
12 bit DAC test failed, 0 is written to DAC U241A and B,
ADC U242 is checked for 133 +/- 7 counts
A2 Interface Bd
E12
12 bit DAC test failed, 4095 is written to DAC U241A
and 0 to B, ADC U242 is checked for 71 +/- 7 counts
A2 Interface Bd
E13
12 bit DAC test failed, 0 is written to DAC U241A and
4095 to B, ADC U242 is checked for 71 +/- 7 counts
A2 Interface Bd
E14
12 bit DAC test failed, 4095 is written to DAC U241A
and B, ADC U242 is checked for 10 +/- 7 counts
A2 Interface Bd
E15
8 bit DAC test failed, 10 and 240 are written to DAC
U244, ADC U242 is checked for 10 and 240 +/- 7 counts
A2 Interface Bd
E80
Dig I/O test failed, SEC_PCLR written low and high,
read back through Xilinx
A2 Interface Bd
E213
RS-232 input buffer overrun
A2 Interface Bd
E216
RS-232 framing error
A2 Interface Bd
E217
RS-232 parity error
A2 Interface Bd
E218
RS-232 UART input overrun
A2 Interface Bd
E220
Front Panel comm UART input overrun
A3 Front Panel/Display Bd
33
3 - Troubleshooting
E221
Front Panel comm UART framing error
A3 Front Panel/Display Bd
E222
Front Panel comm UART parity error
A3 Front Panel/Display Bd
E223
Front Panel firmware input buffer overrun
A3 Front Panel/Display Bd
CV/CC Status Annunciators Troubleshooting
The CV/CC annunciators are particularly helpful when troubleshooting a unit with no output voltage or
current. If the unit has passed self test the programming DAC circuits on the A2 circuit board are probably
working properly. If either the CV or CC annunciators is on then the problem is in either the CV or CC
control circuits located on the A1 Main board. If UNR is indicated then neither the voltage nor the current
circuits are in control and the problem would be in the main power transformer or the driver or output
regulator stages circuits, also on A1 but after the gating diodes.
Bias and Reference Supplies
Before troubleshooting any circuit check the bias and/or reference voltages to make sure that they are not
the cause. Table 3-3 lists the bias and reference voltage test points for the A1 Main Control , A2 Interface,
and the A3 Front Panel/Display boards. Unless otherwise noted, all voltages are measured with respect to
secondary common (R431-3) with no load on the supply. See Figure 6-1 for test point locations.
Table 3-3. Bias and Reference Voltages
Bias
Test Point
Measurement
A1 E320(Red wire)
+5V +/- 0.15V
A1 E3321(White wire)
+5V
+5V secondary 2
A1 R423 (jumper)
+5V +/- 0.2V
+15V secondary 2
A1 R419 (jumper)
+15V +/- 0.6V
A1 R422 (jumper)
-15V +/- 0.6V
6611C +Rail 3
A1 Main Heat Sink
+20V +/- 10% (50mV P/P)
6612C +Rail
3
A1 Main Heat Sink
+32V +/- 10% (120mV P/P)
6613C +Rail
3
A1 Main Heat Sink
+81V +/- 10% (300mV P/P)
6614C +Rail 3
A1 Main Heat Sink
+130V +/- 10% (400mV P/P)
A1 D307 Anode
-6.8 to - 9.1V (100mV P/P)
+5V primary 1
+5V primary (unreg)
-15V secondary
-Rail
3
2
1
1
Measured with respect to Primary common (Black wire at A1 E324).
2
Measured with respect to Secondary common (R431-3).
3
Measured with respect to - Output at nominal ac input line voltage.
34
Troubleshooting - 3
J307 Voltage Measurements
Cable W9 connects J307 of the A1 Main Board Assembly to J207 of the A2 Interface Assembly. Table 3-4
provides a quick method of determining if the voltages between these assemblies are within the normal
range. If any of these voltages is outside the normal range, refer to the flowcharts to further troubleshoot the
circuit associated with the abnormal voltage.
Table 3-4. Voltage Measurements at J207 (A2 Interface to A1 Main board)
A1J207
Pin #
Signal Name
CV Mode
Full Scale Voltage
No Load
CC Mode
Full Scale Voltage
Full Load
1
PM_INHIBIT (Enabled)
0
0
2
OV_SCR*
+5
+5
3
OV_PROG
+3.9
+3.9
4
FAN_PROG
+2.8
+3.8
5
OV_DETECT*
+5
+5
6
SW_POS (Norm)
+5
+5
7
RANGE_SELECT (High)
0
0
8
OS_TRIM_NEG (COMP)
+1.7
+1.7
OS_TRIM_NEG (SCPI)
+4.0
+4.0
9
+5Vs
+5
+5
10
COMMON
0
0
11
COMMON
0
0
12
+15Vs
+15
+15
13
-15Vs
-15
-15
14
HS_THERM (@25C)
+2.5
+2.5
15
FUSE
+2.4
+2.6
16
IMON_H
0
+3.5
17
IMON_L
IMON_L (@20mA Out)
0
+4.8
+14.7
+4.8
18
IMON_P
0
0
19
VMON
+4.8
+4.8
20
COMMON
0
0
21
COMMON
0
0
22
COMMON
0
0
23
COMMON
0
0
24
CV_PROG
-4.8
-4.8
25
CC_PROG
-4.8
-4.8
26
CC_DETECT*
+5
0
27
CCN_DETECT*
+5
+5
28
CV_DETECT*
0
+5
35
3 - Troubleshooting
Manual Fan Speed Control
Under some circumstances such as testing acoustical devices where the fan noise would interfere with the
test, it would be advantageous to reduce the fan speed. If the test requires a very light load, the ambient
temperature is low and the duration of the test is short, the fan speed may be temporarily reduced. The turnon default is "Automatic" so this procedure must be performed, as needed, every time the line voltage is
turned on. To manually control the fan speed:
a.
Simultaneously depress the "0" and "1" keys. EEINIT <model> will be displayed.
b.
Using the Up/Down annunciator keys select FAN:MODE<AUTO.>.
c.
Using the Up/Down arrows select FAN:MODE <MAN>
d.
Press "Enter"
e.
Simultaneously depress the "0" and "1" keys. EEINIT <model> will be displayed.
f.
Using the Up/Down annunciator keys select FAN:SPEED <data>
g.
Press "Enter Number".
h.
Enter the desired speed (numeric entry range is 0 to 100%)
i.
Press "Enter"
Disabling Protection Features
The power supply's protection features may be disabled. This is not recommended as a normal operating
condition but is helpful under some circumstances such as troubleshooting. The turn-on default is "NOPROTECT OFF" (protection enabled) so this procedure must be performed, as needed, every time the line
voltage is turned on. The overvoltage protection function is not disabled by this procedure. To disable the
protection:
a.
Simultaneously depress the "0" and "1" keys. EEINIT <model> will be displayed.
b.
Using the Up/Down annunciator keys select NO-PROTECT <OFF>.
c.
Using the Up/Down arrows select NO-PROTECT <ON>.
d.
Press "Enter"
36
Troubleshooting - 3
Post-repair Calibration
Calibration is required annually and whenever certain components are replaced. If either A1 or A2 are
replaced, the supply must be re-calibrated as described in Appendix B of the User's Guide.
If the Interface board A2 is replaced, the supply must be initialized first (see "Initialization" later in this
chapter) and then be calibrated.
Inhibit Calibration Switch
If "CAL DENIED" appears on the display when calibration is attempted, or if error code 401 occurs when
calibrating over the GPIB, the internal INHIBIT CAL switch has been set. This switch setting prevents
unauthorized or inadvertent power supply calibration. You must reset this switch in order to calibrate the
supply.
This four-section switch, S201, is located on the A2 Interface board near the GPIB connector. The switch
has 2 functions related to calibration. One is Inhibit Calibration. With this switch set the supply will not
respond to calibration commands, thus providing security against unauthorized calibration. The other
switch allows you to bypass the password in case it is forgotten.
Switch 3
Switch 4
Normal
Off
Off
Clear
Password
Off
On
Inhibit
Calibration
On
Off
4 3 2 1
ON
S201
Calibration Password
In order to enter the calibration mode, you must use the correct password as described in Appendix B of
the User’s Guide. As shipped from the factory, the number 0 (zero) is the password. If you use an incorrect
password, "OUT OF RANGE" will appear on the display for front panel calibration (or error code 402
occurs for GPIB calibration) and the calibration mode will not be enabled.
If you have changed the password and have forgotten it, you can set the configuration switch on A2
Interface board to bypass the password. See "Calibration Switch" paragraph above.
37
3 - Troubleshooting
Initialization
The dc power supply's GPIB address and model number as well as other constants which are required to
program and calibrate the supply are stored in a EEPROM on the A2 Interface board. The Interface board
also contains references and other components that will affect the alignment of the supply. If the Interface
board is replaced, the supply must be reinitialized and calibrated. To initialize the power supply:
a.
Enable the Calibration mode
b.
Simultaneously depress the "0" and "1" keys.
c.
Using the Up/Down arrows select the appropriate model number
d.
Press "Enter"
The dc power supply will go through the turn-on self test sequence. It is now re-initialized and must be
calibrated. See Appendix A of the User’s Guide for the calibration procedure.
ROM Upgrade
Identifying the Firmware
You can use the *IDN? query to identify the revision of the supply's firmware. The query will readback the
revisions of the Primary Interface ROM located on the A2 Interface board. The manufacturer and model
number of the supply are also returned. The following is a sample program:
10
20
30
40
50
ALLOCATE L$[42]
OUTPUT 705;"*IDN?"
ENTER 705;L$
DISP L$
END
The computer will display the manufacturer's name, the model number, a "0," and then the firmware
revision. Example: "AGILENT TECHNOLGIES,66312A,0,A.00.01". The revision level of the ROM can
also be found on the label affixed to the physical IC chip itself.
Upgrade Procedure
If the Interface board ROM is upgraded you can re-initialize the supply without affecting the calibration.
a.
Enable the Calibration mode.
b.
Simultaneously depress the "0" and "1" keys. EEINIT <model> will be displayed.
c.
Using the Up/Down annunciator keys select ROMUPD <model>.
d.
Using the Up/Down arrows select the appropriate model number.
e.
Press "Enter".
The supply will go through the turn-on self test sequence and return to the power supply metering mode.
38
Troubleshooting - 3
Disassembly Procedures
The following paragraphs provide instructions on how to disassemble various components of the dc power
supply. Once disassembled, the components can be reassembled by performing the disassembly
instructions in reverse order. Figure 3-2 shows the location of the major components of the unit.
Figure 3-2. Component Location
WARNING:
SHOCK HAZARD. To avoid the possibility of personal injury, turn off AC power and
disconnect the line cord before removing the top cover. Disconnect the GPIB cable and
any loads, and remote sense leads before attempting disassembly.
CAUTION:
Most of the attaching hardware is metric. Use of other types of fasteners will damage
threaded inserts. Refer to the list of required tools when performing disassembly and
replacement.
List of Required Tools
a.
2PT Pozidriv screwdrivers.
b.
T10 and T15 Torx screwdrivers.
c.
Hex drivers: 7 mm for GPIB connector,
3/16" for RS-232 connector,
1/4" for front panel binding posts
d.
Long nose pliers.
e.
Antistatic wrist discharge strap.
39
3 - Troubleshooting
Cover, Removal and Replacement
a.
Using a T15 Torx screwdriver, unscrew the two captive screws which hold the rear bezel to the dc
power supply, and then remove the two screws from the bottom of the case.
b.
Slide the cover backward until it clears the rear of the power supply.
A2 Interface Board, Removal and Replacement
To remove the Interface Board, proceed as follows:
a.
Remove the cover of the power supply as described under, "Cover Removal and Replacement."
b.
Remove the two 7 mm and two 3/16 inch hex screws that hold the GPIB and RS-232 connectors in
place.
c.
Slide the board forward and lift the right side of the board and slide it out.
d.
Unplug the 3 conductor cable from J206. Depress the release button located at the end of the connector
where the wires enter the housing.
e.
Unplug the flat cables. Note the position of the conductive side for reinstallation. Connectors release
the cable by pulling out end tabs as shown by the arrows in the following figure.
f.
To reinstall the Interface board, perform the above steps in reverse order.
Front Panel Assembly, Removal and Replacement
This procedure removes the front panel assembly from the dc power supply.
a.
Remove the Power Supply Cover as described earlier in, "Top Cover Removal and Replacement."
b.
Disconnect the cable between the Front Panel board and the Interface board at the Interface board. You
may have to remove the Interface board as described above to accomplish this.
c.
Using a Torx T10 driver remove the screw from the right side of the supply that holds the front panel
bracket to the chassis.
d
Unplug the Binding Post cable.
e.
Locate and carefully peel off the left vinyl trim to gain access to the side screw that secures the front
panel to the chassis. Using a Torx T15 driver remove the screw located behind the vinyl trim.
f.
Place the power switch in the on position and slide the switch extension forward as far as it can go and
lift up to disengage from switch. Remove extension from the unit.
g.
Rotate front panel forward from right side to disengage left mounting studs and pull forward.
h.
To remove the right bracket, depress the plastic tab located behind the front panel in the upper right
corner.
i.
To reinstall the Front Panel Assembly, perform the above steps in reverse order.
40
Troubleshooting - 3
A3 Front Panel Board, Removal and Replacement
First remove the front panel assembly as described under, "Front Panel Assembly, Removal and
Replacement." Once you have access to the front panel board perform these steps:
a.
Remove the RPG knob by pulling it away from the front panel.
b.
Pull back the right side of the board near the RPG about 1/8th of an inch. Slide the board to the left to
disengage the holding clips.
c.
To reinstall the Front Panel board, perform the above steps in reverse order.
A1 Main Control Board
a.
Remove the top cover and the A2 Interface board as described above.
b.
Disconnect all cables going to connectors on the main control board.
NOTE:
Be sure to note the position and orientation of all cables prior to removal so that no
mistake is made later when reinstalling these cables.
c.
Disconnect the ground wire between the main board and the chassis. This wire is secured to the side of
the chassis near the AC input by a Torx T10 screw.
d.
Remove two Torx T15 screws which secure the main control board to the chassis.
e.
Remove the Torx 15 screw that holds the main rectifier in the front right corner of the board.
f.
Slide the main board towards the front panel to release it from chassis mounted standoff and then lift
the board out of the chassis.
T1 Power Transformer, Removal and Replacement
To remove the power transformer, the front panel assembly must first be removed to gain access to the
bracket screws that hold the transformer in place.
a.
Remove the front panel assembly as described above.
b.
Remove the two Torx T10 screws securing the rear of the transformer bracket to the bottom of the
chassis and the two screws securing the front of the bracket.
c.
Use long nose pliers to disconnect all wires going to the transformer terminals.
d.
Lift the transformer out of the chassis.
NOTE:
The AC power connections at the transformer primary are line voltage dependent. Refer
to Figure 3-3 subsequent reconnection.
41
3 - Troubleshooting
Line Voltage Wiring
Figure 3-3 illustrates the primary wiring configuration of the power transformer for various ac line voltages.
Use long nose pliers to disconnect the wires going to the transformer terminals.
NOTE:
Install the correct fuse when changing the ac line voltage from a previous setting:
for 110/120 Vac: 2.5AT, 250V, Agilent p/n 2110-0633;
for 220/230 Vac: 1.25AT, 250V, Agilent p/n 2110-0788
grey
white/red/grey
orange
orange
1
2
3
4
5
6
7
120 VAC
orange
white/violet
white/yellow
Top part of
transformer
grey
Front of unit
orange
(spare)
1
2
3
4
5
6
7
220 VAC
Top part of
transformer
white/red/grey
Front of unit
grey
grey
orange
orange
white/red/grey
1
2
3
4
5
6
7
100 VAC
orange
(spare)
orange
white/violet
white/yellow
Top part of
transformer
Front of unit
white/red
white/black
white/brown
1
2
3
4
5
6
7
white/red/grey
All Voltages
Bottom part of
transformer
230 VAC
Top part of
transformer
Front of unit
white/red
red
white/black
black
white/brown
Front of unit
Figure 3-3. Transformer Wiring
42
white/violet
white/yellow
white/violet
white/yellow
4
Principles of Operation
Introduction
This section describes the different functional circuits used in the dc power supply. First, the I/O external
signals that connect to the Agilent power supply are described. Next, the overall block diagrams for the
dc power supply are described in detail.
The simplified block diagrams found in Chapter 6 show the major circuits on the dc power supply as well
as the signals between circuits. They also show the reference designations of some of the components in the
functional circuit.
I/O Interface Signals
Table 4-1 describes the interface signals between the power supply and the end user (or other external
circuits and devices).
Table 4-1. Power Supply Interface signals
Connector
Signal
Description
Front panel outputs
+OUT
-OUT
Positive DC output voltage
Negative DC voltage (or return)
Rear panel
output/sense screw
terminals
+OUT
-OUT
+ sense
- sense
common
Positive DC output voltage
Negative DC voltage (or return)
+OUT sensing terminal1
-OUT sensing terminal1
connected to ground conductor
1
Set SENSE switch to "Remote" when using the sensing
terminals.
INH/FLT connector
pin 1
pin 2
pin 3
pin 4
FLT/INH mode2
FLT output
FLT Common
INH Input
INH Common
2
Digital I/O mode
OUT 0
OUT 1
IN 2/OUT 2
Common
as-shipped configuration
RS-232 connector
XON-XOFF
RTS-CTS
DTR-DSR
NONE
uses ASCII control codes DC# and DC1
uses Request-To-Send and Clear-To-Send lines
uses Data-Terminal-Ready and Data-Set-Ready lines
there is no flow control
GPIB connector
GPIB/IEEE 488
Provides the interface to an external GPIB controller
Ac input connector
ac mains
Can be 100 Vac, 120 Vac, 220 Vac or 240 Vac Input
43
4 - Principles of Operation
A3 Front Panel Circuits
As shown in Figure 6-3, the supply's front panel assembly contains a circuit board, a keypad, a display, and
a rotary control (RPG) for the output voltage and current. With the exception of the RPG (A3G1), the A3
Front Panel board is an assembly-level replaceable part. A separate front panel binding post board is also
included on the unit. It is also available as an assembly-level replaceable part.
The A3 front panel board contains microprocessor circuits, which decode and execute all keypad and RPG
commands that are transferred to the power supply output via the serial I/O port to the primary interface
circuits on the A2 interface board. The front panel microprocessor circuits also process power supply
measurement and status data received on the serial I/O port and send them to the display.
A2 Interface Circuits
The circuits on the A2 interface board provide the interface between the GPIB interface, RS-232 interface,
and front panel interface and the dc power supply. Communication between the power supply and a GPIB
controller is processed by the GPIB interface and the primary microprocessor circuits on the A2 board. The
A2 Interface board is assembly-level replaceable; it contains no user-replaceable parts.
With the exception of the front panel microprocessor, all digital circuits, analog-to-digital converters (ADC)
and digital-to-analog converters (DAC) in the dc power supply are located on the A2 Interface board.
Control signals between the A2 interface board and the A1 main board are either analog or level signals.
Primary Interface
The primary microprocessor circuits (DSP, ROM, and RAM chips) decode and execute all instructions
and control all data transfers between the controller and the secondary interface. The primary
microprocessor circuits also processes measurement and status data received from the secondary interface.
A Dual Asynchronous Control chip on the A2 board converts the RS-232, RI/DFI, and front panel data into
the primary microprocessor's 8-bit data format. The serial data is transferred between the primary interface
and the secondary interface via a serial bus and optical isolator chips. These chips isolate the primary
interface circuits (referenced to earth ground) from the secondary interface circuits (referenced to the
supply’s output common).
Secondary Interface
The secondary interface circuits include a programmed logic array, EEPROM, boot-ROM, 8 and 12-bit
DAC circuits, and 8 and 16-bit ADC circuits. The programmed logic array translates the serial data
received from the primary interface into a corresponding digital signal for the appropriate DAC/ADC
circuits. The logic array is also connected directly to four DAC/ADC circuits. Under control of the logic
array, the selected DAC converts the data on the bus into an analog signal. Conversely, the selected ADC
converts the analog signals from the A1 board into a digital signal.
The logic array also directly receives status information from the A1 main board via three level-sensitive
signal lines, which inform the array of the following operating conditions: constant voltage mode
(CV_Detect*), constant current mode (CC_Detect*), and overvoltage (OV_Detect*). The PM_Inhibit
control signal is used to shut down the bias voltage to the output stages and keep the power supply output
off. The OV_SCR* control signal is used to fire the SCR and keep the power supply output off when an
overvoltage condition has occurred.
44
Principles of Operation - 4
The EEPROM (electrically erasable programmable read-only memory) chip on the A2 interface board
stores a variety of data and configuration information. This information includes calibration constants,
GPIB address, present programming language, and model-dependent data, such as the minimum and
maximum values of voltage and current. One of the EEPROM storage locations holds a checksum value
which is used to verify the integrity of the EEPROM data. Access to the calibration data in the EEPROM is
controlled by the combination of a password and switch settings on A2S201, located on A2 interface board
(See Chapter 3 "Inhibit Calibration Switch").
The Dual 12-bit DAC converts the programmed value of voltage and current on the bus into the CV_Prog
and CC_Prog signals, which are sent to the CV control circuits in order to control the magnitude of the
output voltage in the CV mode and output current in CC mode. The CV_Prog and CC_Prog signals are in
the 0 to -5 V range, which corresponds to the zero to full-scale output ratings of the dc power supply.
The Quad 8-bit DAC converts programmed information for the following circuits into analog format:
overvoltage setting (OV_Prog), and fan speed programming (Fan_Prog). The OV_Prog signal is applied to
the OV detect circuit, which compares the programmed overvoltage setting with the actual output voltage.
The Fan_Prog signal is applied to the fan speed control circuit in order to speed up the fan as temperature
increases, and to slow the fan speed down as temperature decreases.
The 16-bit ADC in conjunction with a 4x1 multiplexer returns data from the following measurement signals
to the logic array: monitored output voltage (VMon), monitored high-range current (Imon_H), monitored
low-range current (Imon_L), and monitored peak current (Imon_P). All measurement signals are in the
range of 0 to +5V, which corresponds to the zero to full-scale readback capability of the dc power supply.
The 8-channel, 8-bit ADC returns the following signals to the logic array: high-range output current
(Imon_H), overvoltage (V_Mon), ambient temperature (Temp_Amb), heatsink temperature (HS_Therm),
and output fuse state (Fuse). Four of these signals are for fan control. The logic array varies the Fan_Prog
signal depending upon the ambient temperature, the heatsink temperature, and the present output voltage
and current. The Fuse signal informs the logic array if the output fuse (F309) is open.
A1 Main Board Circuits
Power Circuits
As shown in Figures 6-2 and 6-4, the power circuits consist of: input power rectifiers and filter, primary and
secondary bias circuits, an output regulator, a downprogrammer circuit, current-monitoring resistors, an
overvoltage SCR, and an output filter. All bias circuits are located on the A1 PC board. Bias voltage test
points are shown in Figure 6-1 and transformer wiring diagrams are shown in Figure 3-3.
The primary bias circuits are referenced to chassis (earth) ground. They provide the bias for the GPIB,
RS232 and RI/DFI interfaces, the interface micro-processor circuits and the front panel.
The secondary bias circuits are referenced to secondary (output) common and are isolated from the chassis
ground. They provide the bias for the amplifier and output circuits located on the A1 PC board. They also
provide the bias for the logic array, EEPROM, DAC and ADC circuits and the secondary side of the Optoisolators on A2.
45
4 - Principles of Operation
As shown in Figure 6-2, the ac input rectifier and filter converts ac input to a dc level. The output regulator
regulates this dc level at the output of the power supply. The output regulator stage consists of two parallel
NPN series regulators mounted on a heatsink and connected between the +Rail and the +Output. The
conduction of these series regulators is increased or decreased by the Control signal from the CV/CC
control circuits in order to regulate the output voltage (in CV mode), or output current (in CC mode).
An NPN downprogramming transistor is connected between the +Output and the -Rail. The conduction of
the downprogramming transistor is controlled by the DP_Control signal from the CV/CC control circuits.
Whenever the output voltage is greater than the programmed voltage setting, the downprogramming
transistor conducts and shunts current away from the load until the output voltage equals the programmed
setting.
The SCR, connected across the output, will fire and short the output when an overvoltage condition is
detected. The SCR is controlled by the OV_SCR* signal from the crowbar control circuit (described in the
next section).
Two current shunt resistors (RmHi and RmLo) monitor the output current. RmHi monitors the high current
range; RmLo monitors the low current range. Shunt clamps are connected in parallel across RmLo to limit
the voltage across RmLo to about 2 volts. This corresponds to approximately 25 mA (the maximum rating
of the low current range).
The output filter capacitor provides additional filtering of the dc output.
Control Circuits
As shown in Figure 6-2, the control circuits consist of the CV/CC control, output voltage/current monitor,
bias supplies, and SCR control.
The CV/CC control circuits provide a CV control loop and a CC control loop. For any value of load
resistance, the supply must act either as a constant voltage (CV) or as a constant current (CC) supply.
Transfer between these modes is accomplished automatically by the CV/CC control circuit at a value of
load resistance equal to the ratio of the programmed voltage value to the programmed current value. A low
level CV_Detect* or CC_Detect* signal is returned to the secondary interface to indicate that the
corresponding mode is in effect.
With the CV loop in control, the output voltage is regulated by comparing the programmed voltage signal
CV_Prog (0 to -5V) with the output voltage monitor signal VMon. The VMon signal is in the 0 to +5 V
range, which corresponds to the zero to full-scale output voltage range of the supply. If the output voltage
exceeds the programmed voltage, the Control signal goes low, causing the output regulator to conduct less
and decrease the output voltage. Conversely, if the output voltage is less than the programmed voltage, the
Control signal goes high, causing the regulator to conduct more and increase the output voltage. Depending
upon the position of the Sense switch, the output voltage is either monitored at the supply's output terminals
(local), or at the load (remote), using the +S and -S terminals with remote sense leads connected to the load.
If the output voltage goes higher than the programmed value, the downprogramming stage is turned on.
With the CC loop in control, the output current is regulated by comparing the programmed current signal
CC_Prog (0 to -5V), with the output current monitor signal Imon_H. The Imon_H signal is produced by
measuring the voltage drop across current monitoring resistor and is in the 0 to +3.5 V range, which
corresponds to the zero to full-scale output current range. If the output current exceeds the programmed
value, the Control signal goes low, causing the output regulator to conduct less and thus decrease the output
current. Conversely, if the output current is less than the programmed value, the Control signal goes high,
causing the output transistors to conduct more and increase the output current. A gross current limit circuit
protects the output if the output current exceeds the maximum current rating of the unit.
46
Principles of Operation - 4
When the downprogramming stage is turned on (in either CV or CC mode), the CV/CC control circuit
causes the Control signal to go low, which in turn causes the downprogramming transistors to conduct
current away from the load and speed up downprogramming.
During operation, a PM_Inhibit signal will cause the output stage bias/shutdown circuit to turn off the gated
15 V bias voltages and shut down the output if any of the following occur:
The output is programmed off.
An overvoltage condition is detected (OV_Detect* signal is received).
The line voltage falls below 90 volts (approximately).
Current readback is provided by three separate circuits. The previously discussed high range current signal
(Imon_H) returns the high range currrent measurement. When the unit is operating in the low current
readback mode, a separate low range current shunt and amplifier provides low-current readback via the
Imon_L signal . A shunt clamp (Q302 and Q304) clamps the voltage across RmLo to approximately 1.8 V.
The third current readback circuit consists of a high bandwidth current amplifier that returns dynamic
current measurements from the output filter capacitor via the Imon_P signal. Note that the Imon_H and the
Imon_P signals are combined to return the actual output current measurement.
An overvoltage detect circuit compares the output voltage to the programmed overvoltage setting. When the
output exceeds the programmed setting, the OV_Detect* signal goes low, which informs the logic array that
an OV condition has occurred. The crowbar control circuit is enabled when the OV_SCR* signal is
received. When an overvoltage condition occurs, the SCR control circuit generates the OV signal, which
causes the following actions to occur:
1. The SCR fires, shorting the supply's output.
2. The microprocessor circuits are notified of the OV condition (OV_Detect* is low) in order to
program the ouput off, turn off the gated 15V bias supplies, and update the status of the unit.
3. The PM_Inhibit signal goes high, programming the output off and shutting down the gated 15V bias
for the output regulators.
4. When a output protection clear command is executed, the microprocessor circuits resets the OV
circuits, turns on the gated 15V biases, and programs the output to its previous level.
The fan driver control circuit provides the DC voltage to operate the cooling fan. The Fan_Prog signal
from the secondary interface circuit varies this voltage according to the ambient and heatsink temperature as
well as the output voltage and current of the supply.
47
5
Replaceable Parts List
Introduction
This section lists the replaceable parts for all models. Refer to Figures 5-1 and 5-2 for the
location of mechanical parts with the reference designators MP.
Designator
A1
A1
A1
A1
A2
A3
A4
A6
B1
F301
F301
F303
F305
F306
F308
F309
F309
F309
F309
F310
F311
F311
F311
F311
G1
T1
T1
T1
T1
W-1
W-2
Part_Number
06611-61024
5063-3497
06613-61020
06614-61020
5063-4874
5063-3430
06611-60022
5063-3434
06632-60002
2110-0633
2110-0788
2110-0699
2110-0699
2110-0699
2110-0932
2110-0685
2110-0967
2110-0967
2110-0967
2110-0932
2110-0946
2110-0932
2110-0936
2110-0936
0960-0892
9100-5187
9100-5399
9100-5186
9100-5188
06611-80003
5063-3480
Table 5-1. Chassis, Electrical
Qty
Description
1
6611C Control PCA
1
6612C Control PCA
1
6613C Control PCA
1
6614C Control PCA
1
Interface PCA
1
Front Panel PCA
1
Binding Post PCA
1
Relay Board (Optional)
1
Fan Assembly
1
Fuse, 2.5AT, 250V (115Vac input)
1
Fuse, 1.25AT, 250V (230Vac input)
1
Fuse, sub-min, 5AM, 125V
1
Fuse, sub-min, 5AM, 125V
1
Fuse, sub-min, 5AM, 125V
1
Fuse, smt, 5AM, 125V
1
Fuse, sub-min, 7AT 125V (6611C Output Fuse)
1
Fuse, sub-min, 4AT 125V (6612C Output Fuse)
1
Fuse, sub-min, 4AT 125V (6613C Output Fuse)
1
Fuse, sub-min, 4AT 125V (6614C Output Fuse)
1
Fuse, smt, 5AM, 125V
1
Fuse, smt, 10AM 125V (6611C)
1
Fuse, smt, 5AM, 125V (6612C)
1
Fuse, smt, 4AM 125V (6613C)
1
Fuse, smt, 4AM 125V (6614C)
1
Rotary pulse generator
1
6611C Main Power Transformer
1
6612C Main Power Transformer
1
6613C Main Power Transformer
1
6614C Main Power Transformer
1
Primary Power Cable (E312/313 to T1)
1
Secondary Power Cable (T1 to J304)
49
5 - Replaceable Parts List
W-3
W-4
W-5
W-6
W-7
W-8
W-9
W-10
W-11
50
5063-4825
5063-3479
5063-3481
5063-3478
5080-2544
5080-2452
5080-2448
06611-60056
5080-2605
8120-4383
8120-1351
8120-1369
8120-1689
8120-0698
8120-2104
8120-2956
8120-4211
8120-4753
5962-8194
5962-8198
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
Secondary Power Cable (T1 to J306)
Secondary Bias Cable (T1 to J305)
Output Cable (EB315/ER315 to front panel)
Primary Bias Cable (T1 to J303)
Display Power/Comm Cable (A2 to A3)
Interface Power Cable (E320/321 to A2J206)
Interface Signal/Bias Cable (A1J307 to A2J207)
T1 Primary Jumper
Relay Cable (J320 to relay board) not used in 6611C
Line Cord, (std U.S. 115Vac input)
Line Cord, Option 900,
Line Cord, Option 901,
Line Cord, Option 902,
Line Cord, Option 904,
Line Cord, Option 906,
Line Cord, Option 912,
Line Cord, Option 917,
Line Cord, Option 918,
User’s Guide
Programming Guide
Replaceable Parts List - 5
Figure 5-1. Mechanical Parts Identification
51
5 - Replaceable Parts List
Designator
MP1
MP2
MP3
MP4
MP5
MP6
MP7
MP8
MP8
MP8
MP8
MP9
MP10
MP11
MP12
MP13
MP14
MP15
MP16
MP17
MP18
MP19
MP20
MP21
MP22
MP23
MP24
MP25
MP26
MP27
MP28
MP29
MP30
MP31
52
Table 5-2. Chassis, Mechanical
Part_Number
Qty
Description
5001-9873
1
Chassis
5063-3413
1
Front Panel
5040-1723
1
Side Bracket, Right
1400-0977
2
Battery Clip
1510-0091
2
Binding Post
0590-0305
2
Hex Nut 6-32 w/Lockwasher
33120-87401
1
Knob
06611-40008
1
Window (6611C)
06612-40003
1
Window (6612C)
06613-40001
1
Window (6613C)
06614-40001
1
Window (6614C)
06611-40001
1
Pushrod (Ref Line Switch)
06611-40002
1
Keypad
5001-9874
1
Cover
03478-88304
1
Rear Bezel
5041-8801
4
Foot
0515-0433
7
Screw M4x0.7x16mm, Torx T15, Pan, Conical cup
06611-00004
1
Transformer Bracket
0515-0430
4
Screw M3x0.5x6mm, Torx T10, Pan, Conical cup
0380-0644
2
Stud Mounted Standoff (ref GPIB Connector)
2190-0586
2
Helical Lock Washer, M4
3050-0849
2
Flat Washer, #10
5040-1722
1
Fan Spacer
0515-2535
2
Screw M3x0.5x8mm, Torx T10, Pan Head, Thread rolling
0515-0374
1
Screw M3x0.5x10mm, Torx T10, Pan, Conical cup
5080-2541
1
Rear Panel Label
1400-0493
1
Cable Tie
5001-0538
2
Side Trim
0515-0383
1
Screw M4x0.7x16mm, Torx T15, Pan, Conical cup
1252-1488
1
Terminal Block, 4 Position, RI/DFI
0360-2604
1
Terminal Block, 5 Position, Output/Sense
0370-2862
1
Pushbutton (Ref Sense Switch)
1252-3056
2
Screw Lock Kit (ref RS232 Connector)
5001-9876
1
Insulator
6
Diagrams
Introduction
None
Blue
-15Vs
+15Vs
+5Vs
R431
Sec Common
F309
+Rail
Heat Sink
Red
Brown
Opt
J320
Grn/Yel
Yellow
Orange
Relay
White
Gray
Violet
This chapter contains drawings and diagrams for troubleshooting and maintaining the Agilent Model
6611C, 6612C, 6613C and 6614C System DC Power Supplies.
Conductor Side
J305
Pri Common
F308
D330
D307
F303
F306
+5Vp
J304
-Rail
F310
F311
J306
J314
J303
F305
J307
+5Vp (unreg)
Figure 6-1. A1 Board Component and Test Point Locations
53
6 - Diagrams
Figure 6-2. A1 Board Block Diagram
54
Diagrams - 6
Figure 6-3. A2/A3 Boards Block Diagram
55
T1
56
Figure 6-4. Rail and Bias Circuits
11Vac
20Vac
20Vac
8Vac
8Vac
Red
20Vac
Black
2
1
J303
3
2
1
J305
3
2
1
J304
2
1
J306
F305
F303
F306
F308
F310
F311
D330
U306
U304
P
R422
Sec Com
+5V Sec
R423
R419
Pri Com
+5V Pri
-15V Sec
S
U307
+15V Sec
+5Vp Unreg
U305
+ 26V
To Fan Circuit
E324
E320
E321
J307
14
White
A1
Black
Red
J206
1
3
2
A2
4 nu
J207
14
10
11
12
21
22
23
27
11
12
21
22
23
27
13
10
13
- RAIL
RAIL_CT
+ RAIL
P
6
7
8
1
2
3
4
5
J211
5V
J111
8
7
6
5
4
3
2
1
A3
5V
P
6 - Diagrams
Index
—+—
+OUT, 43
+sense, 43
—A—
A1 block diagram, 54
A1 board removal, 41
A1 Main board, 45
A1 test point locations, 53
A2 board removal, 40
A2 Interface Board, 44
A2/A3 block diagram, 55
A2S201, 45
A3 board removal, 41
A3 Front Panel, 44
ADC, 44
—B—
bias voltages, 34, 35
—C—
cal denied, 37
calibration, 37
calibration - post repair, 37
CC, 34
CC line regulation, 19
CC load effect, 19
CC load regulation, 19
CC loop, 46
CC noise, 20
CC- operation, 18
CC source effect, 20
CC_Detect*, 44, 46
CC_Prog, 45, 46
clear password, 37
constant current tests, 17
constant voltage tests, 15
Control, 45, 46
copyrights, 5
cover removal, 40
current monitoring resistor, 14
current sink, 18
CV, 34
CV load effect, 15
CV loop, 46
CV Noise, 16
CV source effect, 16
CV/CC control, 45, 46
CV_Detect*, 44, 46
CV_Prog, 45, 46
—D—
DAC, 44
disable protection, 36
disassembly - tools, 39
disassembly procedure, 39
downprogramming, 45, 47
DP_Control, 45
—E—
EEPROM, 45
electronic load, 13
electrostatic discharge, 10
error codes, 33
—F—
F309, 45
fan speed, 36
Fan_Prog, 45, 47
firmware revisions, 10, 38
FLT, 43
front panel removal, 40
Fuse, 45
—G—
GPIB, 43
—H—
hazardous voltages, 9
history, 5
HS_Therm, 45
—I—
identification, 5
IDN? query, 38
Imon_H, 45
IMon_H, 46
Imon_L, 45
Imon_P, 45
INH, 43
inhibit calibration, 37
initialization, 38
interface signals, 43
—J—
J207 voltages, 35
57
Index
—M—
manual revisions, 10
—N—
notice, 5
—O—
-OUT, 43
out of range, 37
OV_Detect*, 44, 47
OV_Prog, 45
OV_SCR*, 44, 46
—S—
safety considerations, 9
safety summary, 3
schematic notes, 53
SCR, 46, 47
secondary interface, 44
self-test, 33
-sense, 43
sense switch, 46
serial number, 5
series regulator, 45
shunt clamp, 46, 47
status annunciators, 34
—T—
—P—
PARD, 16, 20
password, 37
performance test form, 21
performance tests, 14
PM_Inhibit, 47
power-on self-test, 33
primary interface, 44
printing, 5
programming, 14
programming and output values, 14
protection, 36
Temp_Amb, 45
test equipment, 11
test setup, 12
trademarks, 5
transformer removal, 41
transient recovery, 16
troubleshooting - bias and reference supplies, 34, 35
troubleshooting - equipment, 28
troubleshooting - flowcharts, 28
troubleshooting - introduction, 27
troubleshooting - overall, 28
troubleshooting - status annunciators, 34
—U—
—R—
rail and bias circuits, 56
readback accuracy, 15
reference voltages, 34, 35
replaceable parts - chassis, 49
revisions, 10
RmHi, 46
RmLo, 46
ROM upgrade, 38
RPG, 44
RS-232, 43
UNR, 34
—V—
verification tests, 14
VMon, 45, 46
voltage programming, 15
—W—
warranty, 2
58