Keithley 2520 Service Manual

2520-902-01.qxd 5/9/06 10:55 AM Page 1

www.keithley.com

Model 2520 Pulsed Laser Diode Test System

Service Manual

2520-902-01 Rev. B / January 2006

www.keithley.com

Model 2520 Pulsed Laser Diode Test System

Service Manual

2520-902-01 Rev. B / January 2006

A G R E A T E R M E A S U R E O F C O N F I D E N C E A G R E A T E R M E A S U R E O F C O N F I D E N C E

WARRANTY

Keithley Instruments, Inc. warrants this product to be free from defects in material and workmanship for a period of 1 year from date of shipment.

Keithley Instruments, Inc. warrants the following items for 90 days from the date of shipment: probes, cables, rechargeable batteries, diskettes, and documentation.

During the warranty period, we will, at our option, either repair or replace any product that proves to be defective.

To exercise this warranty, write or call your local Keithley representative, or contact Keithley headquarters in

Cleveland, Ohio. You will be given prompt assistance and return instructions. Send the product, transportation prepaid, to the indicated service facility. Repairs will be made and the product returned, transportation prepaid.

Repaired or replaced products are warranted for the balance of the original warranty period, or at least 90 days.

LIMITATION OF WARRANTY

This warranty does not apply to defects resulting from product modification without Keithley’s express written consent, or misuse of any product or part. This warranty also does not apply to fuses, software, non-rechargeable batteries, damage from battery leakage, or problems arising from normal wear or failure to follow instructions.

THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUD-

ING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE.

THE REMEDIES PROVIDED HEREIN ARE BUYER’S SOLE AND EXCLUSIVE REMEDIES.

NEITHER KEITHLEY INSTRUMENTS, INC. NOR ANY OF ITS EMPLOYEES SHALL BE LIABLE

FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING

OUT OF THE USE OF ITS INSTRUMENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS,

INC., HAS BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH DAMAGES. SUCH

EXCLUDED DAMAGES SHALL INCLUDE, BUT ARE NOT LIMITED TO: COSTS OF REMOVAL

AND INSTALLATION, LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY PERSON, OR

DAMAGE TO PROPERTY.

A G R E A T E R M E A S U R E O F C O N F I D E N C E

Keithley Instruments, Inc.

Corporate Headquarters • 28775 Aurora Road • Cleveland, Ohio 44139

440-248-0400 • Fax: 440-248-6168 • 1-888-KEITHLEY (534-8453) • www.keithley.com

12/04

Model 2520

Pulsed Laser Diode Test System

Service Manual

©2001, Keithley Instruments, Inc.

All rights reserved.

Cleveland, Ohio, U.S.A.

Second Printing, January 2006

Document Number: 2520-902-01 Rev. B

Manual Print History

The print history shown below lists the printing dates of all Revisions and Addenda created for this manual. The Revision Level letter increases alphabetically as the manual undergoes subsequent updates. Addenda, which are released between Revisions, contain important change information that the user should incorporate immediately into the manual. Addenda are numbered sequentially. When a new Revision is created, all Addenda associated with the previous Revision of the manual are incorporated into the new Revision of the manual. Each new Revision includes a revised copy of this print history page.

Revision A (Document Number 2520-902-01) ...................................................... September 2001

Revision B (Document Number 2520-902-01) .......................................................... January 2006

All Keithley product names are trademarks or registered trademarks of Keithley Instruments, Inc.

Other brand names are trademarks or registered trademarks of their respective holders.

S

afety Precautions

The following safety precautions should be observed before using this product and any associated instrumentation. Although some instruments and accessories would normally be used with non-hazardous voltages, there are situations where hazardous conditions may be present.

This product is intended for use by qualified personnel who recognize shock hazards and are familiar with the safety precautions required to avoid possible injury. Read and follow all installation, operation, and maintenance information carefully before using the product. Refer to the manual for complete product specifications.

If the product is used in a manner not specified, the protection provided by the product may be impaired.

The types of product users are:

Responsible body is the individual or group responsible for the use and maintenance of equipment, for ensuring that the equipment is operated within its specifications and operating limits, and for ensuring that operators are adequately trained.

Operators use the product for its intended function. They must be trained in electrical safety procedures and proper use of the instrument. They must be protected from electric shock and contact with hazardous live circuits.

Maintenance personnel perform routine procedures on the product to keep it operating properly, for example, setting the line voltage or replacing consumable materials. Maintenance procedures are described in the manual. The procedures explicitly state if the operator may perform them. Otherwise, they should be performed only by service personnel.

Service personnel are trained to work on live circuits, and perform safe installations and repairs of products. Only properly trained service personnel may perform installation and service procedures.

Keithley products are designed for use with electrical signals that are rated Measurement Category I and Measurement Category

II, as described in the International Electrotechnical Commission (IEC) Standard IEC 60664. Most measurement, control, and data I/O signals are Measurement Category I and must not be directly connected to mains voltage or to voltage sources with high transient over-voltages. Measurement Category II connections require protection for high transient over-voltages often associated with local AC mains connections. Assume all measurement, control, and data I/O connections are for connection to

Category I sources unless otherwise marked or described in the Manual.

Exercise extreme caution when a shock hazard is present. Lethal voltage may be present on cable connector jacks or test fixtures.

The American National Standards Institute (ANSI) states that a shock hazard exists when voltage levels greater than 30V RMS,

42.4V peak, or 60VDC are present. A good safety practice is to expect that hazardous voltage is present in any unknown circuit before measuring.

Operators of this product must be protected from electric shock at all times. The responsible body must ensure that operators are prevented access and/or insulated from every connection point. In some cases, connections must be exposed to potential human contact. Product operators in these circumstances must be trained to protect themselves from the risk of electric shock.

If the circuit is capable of operating at or above 1000 volts, no conductive part of the circuit may be exposed.

Do not connect switching cards directly to unlimited power circuits. They are intended to be used with impedance limited sources. NEVER connect switching cards directly to AC mains. When connecting sources to switching cards, install protective devices to limit fault current and voltage to the card.

Before operating an instrument, make sure the line cord is connected to a properly grounded power receptacle. Inspect the connecting cables, test leads, and jumpers for possible wear, cracks, or breaks before each use.

When installing equipment where access to the main power cord is restricted, such as rack mounting, a separate main input power disconnect device must be provided, in close proximity to the equipment and within easy reach of the operator.

For maximum safety, do not touch the product, test cables, or any other instruments while power is applied to the circuit under test. ALWAYS remove power from the entire test system and discharge any capacitors before: connecting or disconnecting ca-

5/03

bles or jumpers, installing or removing switching cards, or making internal changes, such as installing or removing jumpers.

Do not touch any object that could provide a current path to the common side of the circuit under test or power line (earth) ground. Always make measurements with dry hands while standing on a dry, insulated surface capable of withstanding the voltage being measured.

The instrument and accessories must be used in accordance with its specifications and operating instructions or the safety of the equipment may be impaired.

Do not exceed the maximum signal levels of the instruments and accessories, as defined in the specifications and operating information, and as shown on the instrument or test fixture panels, or switching card.

When fuses are used in a product, replace with same type and rating for continued protection against fire hazard.

Chassis connections must only be used as shield connections for measuring circuits, NOT as safety earth ground connections.

If you are using a test fixture, keep the lid closed while power is applied to the device under test. Safe operation requires the use of a lid interlock.

If a screw is present, connect it to safety earth ground using the wire recommended in the user documentation.

The

!

symbol on an instrument indicates that the user should refer to the operating instructions located in the manual.

The symbol on an instrument shows that it can source or measure 1000 volts or more, including the combined effect of normal and common mode voltages. Use standard safety precautions to avoid personal contact with these voltages.

The symbol indicates a connection terminal to the equipment frame.

The WARNING heading in a manual explains dangers that might result in personal injury or death. Always read the associated information very carefully before performing the indicated procedure.

The CAUTION heading in a manual explains hazards that could damage the instrument. Such damage may invalidate the warranty.

Instrumentation and accessories shall not be connected to humans.

Before performing any maintenance, disconnect the line cord and all test cables.

To maintain protection from electric shock and fire, replacement components in mains circuits, including the power transformer, test leads, and input jacks, must be purchased from Keithley Instruments. Standard fuses, with applicable national safety approvals, may be used if the rating and type are the same. Other components that are not safety related may be purchased from other suppliers as long as they are equivalent to the original component. (Note that selected parts should be purchased only through Keithley Instruments to maintain accuracy and functionality of the product.) If you are unsure about the applicability of a replacement component, call a Keithley Instruments office for information.

To clean an instrument, use a damp cloth or mild, water based cleaner. Clean the exterior of the instrument only. Do not apply cleaner directly to the instrument or allow liquids to enter or spill on the instrument. Products that consist of a circuit board with no case or chassis (e.g., data acquisition board for installation into a computer) should never require cleaning if handled according to instructions. If the board becomes contaminated and operation is affected, the board should be returned to the factory for proper cleaning/servicing.

Table of Contents

1

2

Performance Verification

Introduction ................................................................................

1-2

Verification test requirements ....................................................

1-4

Environmental conditions ...................................................

1-4

Warm-up period ..................................................................

1-4

Line power ..........................................................................

1-4

Recommended test equipment ...................................................

1-5

Resistor characterization .....................................................

1-5

Verification limits ......................................................................

1-6

Example limits calculation ..................................................

1-6

Restoring factory defaults ..........................................................

1-6

Performing the verification test procedures ...............................

1-6

Test summary ......................................................................

1-6

Test considerations .............................................................

1-7

Testhead connections .................................................................

1-7

Voltage measurement accuracy .................................................

1-8

Current source accuracy .............................................................

1-9

Current measurement accuracy ................................................ 1-13

Voltage bias source accuracy ................................................... 1-15

Calibration

Introduction ................................................................................

2-2

Environmental conditions ..........................................................

2-4

Temperature and relative humidity .....................................

2-4

Warm-up period ..................................................................

2-4

Line power ..........................................................................

2-4

Calibration considerations ..........................................................

2-4

Calibration cycle .................................................................

2-5

Recommended calibration equipment ................................

2-5

Resistor characterization .....................................................

2-5

Calibration menus ......................................................................

2-6

Unlocking calibration .................................................................

2-7

Unlocking calibration from the front panel ........................

2-7

Unlocking calibration by remote ........................................

2-7

Changing the password ..............................................................

2-8

Changing the password from the front panel ......................

2-8

Changing the password by remote ......................................

2-8

Resetting the calibration password ............................................

2-8

Viewing calibration dates and calibration count ........................

2-9

3

4

5

Calibration errors ........................................................................

2-9

Front panel error reporting ..................................................

2-9

Remote error reporting ........................................................

2-9

Aborting calibration steps ...........................................................

2-9

Testhead connections ................................................................ 2-10

Front panel calibration .............................................................. 2-10

Remote calibration .................................................................... 2-22

Remote calibration command summary ............................ 2-22

Remote calibration procedure ........................................... 2-23

Routine Maintenance

Introduction ................................................................................

3-2

Line fuse replacement .................................................................

3-2

Troubleshooting

Introduction ................................................................................

4-2

Safety considerations ..................................................................

4-2

Repair considerations .................................................................

4-2

Power-on self-test .......................................................................

4-3

Front panel tests ..........................................................................

4-3

KEYS test ............................................................................

4-3

DISPLAY PATTERNS test ................................................

4-3

CHAR SET test ...................................................................

4-4

Principles of operation ................................................................

4-4

Overall block diagram .........................................................

4-5

Analog circuits ....................................................................

4-7

Power supply ..................................................................... 4-10

Digital circuitry ................................................................. 4-11

Troubleshooting ........................................................................ 4-13

Display board checks ........................................................ 4-13

Power supply checks ......................................................... 4-14

Digital circuitry checks ..................................................... 4-15

Analog circuitry checks ..................................................... 4-16

No comm link error .................................................................. 4-17

Disassembly

Introduction ................................................................................

5-2

Handling and cleaning ................................................................

5-2

Handling PC boards ............................................................

5-2

Solder repairs .......................................................................

5-2

Static sensitive devices ...............................................................

5-3

Assembly drawings ....................................................................

5-3

Case cover removal ....................................................................

5-4

6

A

B

Motherboard removal .................................................................

5-4

Front panel disassembly .............................................................

5-5

Removing power components ....................................................

5-6

Power supply module removal ...........................................

5-6

Power module removal .......................................................

5-6

Instrument re-assembly ..............................................................

5-6

Testhead disassembly .................................................................

5-7

Case disassembly ................................................................

5-7

Output board removal .........................................................

5-7

Input board removal ............................................................

5-7

Testhead re-assembly .................................................................

5-7

Replaceable Parts

Introduction ................................................................................

6-2

Parts lists ....................................................................................

6-2

Ordering information .................................................................

6-2

Factory service ...........................................................................

6-2

Component layouts ....................................................................

6-2

Specifications

Accuracy calculations ............................................................... A-8

Measurement accuracy ...................................................... A-8

Source accuracy ................................................................. A-8

Calibration Reference

Introduction ............................................................................... B-2

Command summary .................................................................. B-2

Miscellaneous commands ......................................................... B-3

Measurement commands ........................................................... B-6

Current source commands ......................................................... B-7

Voltage bias source commands ................................................. B-8

Detecting calibration errors ....................................................... B-9

Reading the error queue ..................................................... B-9

Error summary ................................................................... B-9

Status byte EAV (Error Available) bit .............................

B-10

Generating an SRQ on error ............................................

B-10

Detecting calibration step completion .....................................

B-10

Using the *OPC? query ...................................................

B-10

Using the *OPC command ..............................................

B-11

Generating an SRQ on calibration complete ...................

B-11

List of Illustrations

1

Figure 1-1

Figure 1-2

Figure 1-3

Figure 1-4

Figure 1-5

Figure 1-6

Figure 1-7

Figure 1-8

Figure 1-9

Figure 1-10

2

Figure 2-1

Figure 2-2

Figure 2-3

Figure 2-4

Figure 2-5

Figure 2-6

Figure 2-7

Figure 2-8

Figure 2-9

3

Figure 3-1

4

Figure 4-1

Figure 4-2

Figure 4-3

Figure 4-4

Performance Verification

Testhead connections ..........................................................................................

1-7

Connections for voltage measurement verification tests ....................................

1-9

Connections for current source verification tests ............................................. 1-10

Parallel resistor construction ............................................................................. 1-10

Resistor mounting and connections .................................................................. 1-11

Connections for current source pulse verification tests .................................... 1-12

Connections for DETECTOR 1 current measurement verification tests .......... 1-13

Connections for DETECTOR 2 current measurement verification tests .......... 1-14

Connections for DETECTOR 1 voltage bias source verification tests ............ 1-15

Connections for DETECTOR 2 voltage bias source verification tests ............. 1-16

Calibration

Testhead connections ........................................................................................ 2-10

Voltage measurement calibration connections ................................................. 2-12

Current source calibration connections ............................................................ 2-13

Pulse low calibration connections .................................................................... 2-15

Detector 1 voltage bias source calibration connections .................................... 2-16

Detector 2 voltage bias source calibration connections .................................... 2-17

Detector 1 current measurement calibration connections ................................. 2-18

Detector 2 current measurement calibration connections ................................. 2-19

Compliance calibration connections ................................................................. 2-20

Routine Maintenance

Model 2520 rear panel ........................................................................................

3-2

Troubleshooting

Overall block diagram ........................................................................................

4-6

Analog circuitry block diagram ..........................................................................

4-8

Power supply block diagram ............................................................................ 4-10

Digital circuitry block diagram ......................................................................... 4-12

List of Tables

1

Table 1-1

Table 1-2

Table 1-3

Table 1-4

2

Table 2-1

Table 2-2

Table 2-3

Table 2-4

Table 2-5

Table 2-6

Table 2-7

Table 2-8

Table 2-9

Table 2-10

Table 2-11

Table 2-12

Table 2-13

Table 2-14

3

Table 3-1

4

Table 4-1

Table 4-2

Table 4-3

Table 4-4

6

Table 6-1

Table 6-2

Table 6-3

Table 6-4

Table 6-5

B

Table B-1

Table B-2

Performance Verification

Recommended verification equipment ...............................................................

1-5

Voltage measurement accuracy limits ................................................................

1-8

Current source verification limits ..................................................................... 1-12

Current measurement verification limits .......................................................... 1-14

Calibration

Recommended calibration equipment ................................................................

2-5

Calibration menu ................................................................................................

2-6

Calibration execution menu ................................................................................

2-6

Voltage measurement calibration values .......................................................... 2-11

Current source calibration values ..................................................................... 2-13

Pulse low calibration values ............................................................................. 2-14

Current measurement calibration values .......................................................... 2-18

Remote calibration command summary ........................................................... 2-22

Voltage measurement calibration voltages and commands .............................. 2-25

Remote current source calibration summary .................................................... 2-27

Remote pulse low calibration summary ........................................................... 2-29

Remote voltage bias source calibration summary ............................................ 2-31

Remote current measurement calibration currents and commands .................. 2-33

Remote compliance calibration summary ........................................................ 2-36

Routine Maintenance

Power line fuse ...................................................................................................

3-3

Troubleshooting

Display board checks ........................................................................................ 4-13

Power supply checks ......................................................................................... 4-14

Digital circuitry checks ..................................................................................... 4-15

Analog circuitry checks .................................................................................... 4-16

Replaceable Parts

Mainframe digital board parts list .......................................................................

6-3

Mainframe display board parts list .....................................................................

6-9

Test head board parts list .................................................................................. 6-10

Pulse board parts list ......................................................................................... 6-13

Miscellaneous parts list ..................................................................................... 6-16

Calibration Reference

Calibration commands ....................................................................................... B-2

Calibration errors ............................................................................................... B-9

1

Performance Verification

1-2 Performance Verification Model 2520 Pulsed Laser Diode Test System Service Manual

Introduction

Use the procedures in this section to verify that Model 2520 Pulsed Laser Diode Test

System accuracy is within the limits stated in the instrument’s one-year accuracy specifications. You can perform these verification procedures:

• When you first receive the instrument to make sure that it was not damaged during shipment.

• To verify that the unit meets factory specifications.

• To determine if calibration is required.

• Following calibration to make sure it was performed properly.

Model 2520 Pulsed Laser Diode Test System Service Manual Performance Verification 1-3

WARNING While the Model 2520 does not incorporate a laser, it is designed to operate (power) laser diode devices. Read all safety precautions listed at the beginning of the Model 2520 User’s Manual. The following safety practices must be used to protect operators and other users of this product from potential exposure to laser radiation:

• Operators must be protected from radiation and electrical hazards at all times.

• The installer must comply with all applicable laws and regulations on laser safety. This requirement includes warning signs and operator training.

• The interlock is required for safe operation. The test fixtures must ensure that the interlock circuit is disabled (source outputs inhibited) so that an operator is not exposed to any radiation. The test fixture interlock must not be defeated.

• The testhead key control must be used to prevent operation unless authorized by the responsible body. This requirement must be part of the facilities administrative controls for laser safety.

Outputs cannot be turned on with the key removed.

• When servicing the test system, any required personnel protection equipment (e.g. laser safety goggles) must be provided by the customer’s responsible body.

• The customer’s laser safety officer (LSO) must review and approve all installations before they are put into operation. Any safety concerns must be immediately reported to the customer’s

LSO.

• If at any time, the indicators provided on the testhead for

INTERLOCK STATUS or LASER POWER ON should fail to light or properly indicate status, immediately contact a Keithley service representative for repair. Failure to do so may expose the user to hazards without proper warnings. See “Interlock status indicator test sequence” in Section 9 of the User’s manual for details on testing the indicator lights.

• Maximum isolation from earth ground is 10V. Exceeding this value may result in a shock hazard.

• When making connections, do not leave any exposed connections.

Ensure that all external circuits are properly insulated.

NOTE If the instrument is still under warranty and its performance is outside specified limits, contact your Keithley representative or the factory to determine the correct course of action.

1-4 Performance Verification Model 2520 Pulsed Laser Diode Test System Service Manual

Verification test requirements

Be sure that you perform the verification tests:

• Under the proper environmental conditions.

• After the specified warm-up period.

• Using the correct line voltage.

• Using the proper test equipment.

• Using the specified output signals and reading limits.

Environmental conditions

Conduct your performance verification procedures in a test environment with:

• An ambient temperature of 18-28°C (65-82°F).

• A relative humidity of less than 70% unless otherwise noted.

Warm-up period

Allow the Model 2520 to warm up for a minimum of one hour before conducting the verification procedures.

If the instrument has been subjected to temperature extremes (those outside the ranges stated above), allow additional time for the instrument’s internal temperature to stabilize.

Typically, allow one extra hour to stabilize a unit that is 10°C (18°F) outside the specified temperature range.

Also, allow the test equipment to warm up for the minimum time specified by the manufacturer.

Line power

The Model 2520 requires a line voltage of 100V to 240V and a line frequency of 50 or

60 Hz. Verification tests must be performed within this range.

Model 2520 Pulsed Laser Diode Test System Service Manual Performance Verification 1-5

Recommended test equipment

Table 1-1 summarizes recommended verification equipment and pertinent specifications.

You can use alternate equipment as long as that equipment has specifications at least as

good as those listed in Table 1-1 . Keep in mind, however, that test equipment uncertainty

will add to the uncertainty of each measurement. Generally, test equipment uncertainty should be at least four times better than corresponding Model 2520 specifications.

Table 1-1

Recommended verification equipment

Description

Calibrator

Manufacturer/Model Specifications

Fluke 5700A 1 DC Voltage: 5V:

10V:

Keithley 2001 2 DC Voltage: 20V:

±5ppm

±5ppm

±22ppm Digital

Multimeter

Precision

Resistors 3

Resistance: 20 Ω

200 Ω

2k Ω

1.2 to 1.6

Ω , 5W, ±5% 4

10 to 15 Ω , 5W, ±5% 4

200 Ω , 2W, ±1%

400 Ω , 1W, ±1%

1k Ω , 0.5W, ±1%

2k Ω , 0.25W, ±1%

±59ppm

±43ppm

±37ppm

Temperature coefficient =

20ppm/°C for all resistors

1. 90-day accuracy specifications of lowest usable range for specified output.

2. 90-day full-range accuracy specifications.

3. Characterize resistors to within ±100ppm using 4-wire ohms function of digital multimeter before use.

4. Use RN60 type: 20 300 Ω in parallel

10 16 Ω in parallel

1-10 2k Ω in parallel

Resistor characterization

The precision resistors listed in Table 1-1

should be characterized to within ±100ppm using the 4-wire ohms function of the digital multimeter before use. Use the characterized values when performing the verification procedure.

1-6 Performance Verification Model 2520 Pulsed Laser Diode Test System Service Manual

Verification limits

The verification limits listed in this section have been calculated using only the

Model 2520 one-year accuracy specifications; they do not include test equipment uncertainty. If a particular measurement falls outside the allowable range, recalculate new limits based on Model 2520 specifications and corresponding test equipment specifications.

Example limits calculation

As an example of how verification limits are calculated, assume you are testing the 10mA measurement range with a 10mA input current. Using the Model 2520 one-year accuracy specification of ±(0.3% of reading + 20 μ A offset), the calculated reading limits are:

Limits = 10mA ± [(10mA × 0.3%) + 20 μ A]

Limits = 10mA ± (30 μ A + 20 μ A)

Limits = 10mA ± 50 μ A

Limits = 9.95mA to 10.05mA

Restoring factory defaults

Before performing the verification procedures, restore the instrument to its factory front panel (BENCH) defaults as follows:

1. Press the SETUP key. The instrument will display the following prompt:

SAVESETUP MENU

SAVE RESTORE POWERON RESET

2. Select RESET, then press ENTER. The unit displays:

RESET ORIGINAL DFLTS

BENCH GPIB

3. Select BENCH, then press ENTER to restore BENCH defaults.

Performing the verification test procedures

Test summary

• Detector current measurement accuracy

• Laser diode voltage measurement accuracy

• Laser diode current source accuracy

• Detector voltage bias source accuracy

If the Model 2520 is not within specifications and not under warranty, see the calibration procedures in Section 2, Calibration, for information on calibrating the unit.

Model 2520 Pulsed Laser Diode Test System Service Manual Performance Verification 1-7

Test considerations

When performing the verification procedures:

• Restore factory front panel defaults as previously outlined.

• Ensure test equipment is fully warmed up and properly connected to the correct

Model 2520 terminals as required.

• Allow signals to settle before making a measurement.

• Do not connect test equipment to the Model 2520 through a scanner, multiplexer, or other switching equipment.

WARNING The maximum common-mode voltage (voltage between LO and chassis ground) is ±10V DC. Exceeding this value may cause a shock hazard.

Testhead connections

The Model 2520 mainframe must be connected to the testhead in order to perform the verification procedures. Using

Figure 1-1 as a guide, make testhead connections as

follows:

CAUTION Make sure power is turned off before making connections.

• Connect mainframe TESTHEAD CONN 1 to testhead MAINFRAME CONN 1.

• Connect mainframe TESTHEAD CONN 2 to testhead MAINFRAME CONN 2.

• Short pins 1 and 9 of the REMOTE INTERLOCK connector. Insert the key in the

KEY INTERLOCK and rotate to the ENABLED position to enable operation.

WARNING Shorting the interlock connector will disable the interlocks. Use caution when performing verification tests.

NOTE Both interlocks must be enabled to perform the verification tests.

1-8 Performance Verification

Figure 1-1

Testhead connections

Model 2520 Mainframe

WARNING:

NO INTERNAL OPERATOR SERVICABLE PARTS, SERVICE BY QUALIFIED PERSONNEL ONLY.

MADE IN

U.S.A.

CAT I

IEEE-488

(CHANGE IEEE ADDRESS

WITH FRONT PANEL MENU)

PULSE

SYNC

OUT

!

DIGITAL I/O

TRIGGER LINK

RS-232

TESTHEAD

CONN 1

!

TESTHEAD

CONN 2

!

LINE FUSE

SLOWBLOW

1.6A, 250V

LINE RATING

100-240VAC

50, 60Hz

140VA MAX.

CAUTION:

FOR CONTINUED PROTECTION AGAINST FIRE HAZARD, REPLACE FUSE WITH SAME TYPE AND RATING.

Model 2520 Pulsed Laser Diode Test System Service Manual

CONN 2 Cable

CONN 1 Cable

Model 2520 Testhead

!

BOTH INTERLOCKS MUST BE ENABLED TO OPERATE

DISABLED

(PULL TO

REMOVE)

KEY

INTERLOCK

1

REMOTE

INTERLOCK

DISABLED

9

ENABLED

GREEN=ENABLED

RED=DISABLED

INTERLOCK

STATUS

ENABLED

LASER

POWER

ON

MAINFRAME

CONN 2

MAINFRAME

CONN 1

Model 2520 Pulsed Laser Diode Test System Service Manual Performance Verification 1-9

Voltage measurement accuracy

Follow the steps below to verify that Model 2520 laser diode voltage measurement accuracy is within specified limits. This test involves applying accurate voltages from a

DC calibrator, and verifying that the Model 2520 voltage readings are within specified limits.

1. With the power off, connect the voltage calibrator to the testhead VOLTAGE

SENSE jacks, as shown in

Figure 1-2

.

2. Turn on the Model 2520 and calibrator, and allow them to warm up for a minimum of one hour.

3. Restore BENCH defaults as covered previously in “Restoring factory defaults” on page 1-6

.

4. Press the LASER V

L

key.

key, then select the Model 2520 5V range with the RANGE

5. Set the calibrator source voltage to +5.0000V, and turn on the output.

6. Press the TRIG key, then verify the Model 2520 voltage reading is within the limits for the 5V range shown in

Table 1-2 .

7. Repeat steps 4 through 6 for the 10V range with a 10V input voltage, as covered in

Table 1-2

.

Table 1-2

Voltage measurement accuracy limits

Model 2520 range

Calibrator voltage

0 5V

10V

0 5.0000V

10.000V

Voltage reading limits

(1 year, 18°C to 28°C)

4.9785 to 5.0215V

9.962 to 10.038V

1-10 Performance Verification Model 2520 Pulsed Laser Diode Test System Service Manual

Figure 1-2

Connections for voltage measurement verification tests

Model 2520 Testhead

Output HI

BIAS

CURRENT

INPUT

DETECTOR 1 DETECTOR 2

!

ISOLATION FROM EARTH: 10V MAX.

HI

CURRENT

OUTPUT

LO

!

CAT I

HI

VOLTAGE

SENSE

LO

VOLTAGE

SENSE HI VOLTAGE

SENSE LO

BNC Cables

Shield

Calibrator (Output DC Voltage)

Output LO

Current source accuracy

Follow the steps below to verify that Model 2520 current source accuracy is within specified limits. This test involves setting the output current to a specific value and measuring the current with a digital multimeter.

1. With the power off, connect the digital multimeter and characterized 10 Ω to 15 Ω resistor to the testhead CURRENT OUTPUT jacks, as shown in

Figure 1-3 .

NOTE See

Figure 1-4

and Figure 1-5

for mounting and connections of parallel resistors.

2. Turn on the Model 2520 and DMM, and allow them to warm up for a minimum of one hour.

3. Restore front panel (BENCH) defaults as outlined previously in

“Restoring factory defaults” on page 1-6 .

4. Select the DC mode as follows: a. Press CONFIG then LASER I

L

.

b. Select SHAPE, then press ENTER.

c. Select DC, then press ENTER.

d. Press EXIT to return to normal display.

5. Press the LASER I

L

key, then the EDIT key, and select the Model 2520 500mA source range with the RANGE key.

6. Select the DMM DC voltage function, and enable auto-range.

7. Press the EDIT key to enter the EDIT mode. Using the EDIT and or numeric keys, set the Model 2520 current source output to 500.00mA, then turn on the outputs by pressing the ON/OFF OUTPUT key.

8. Note the DMM voltage reading, then turn off the output by pressing the ON/OFF

OUTPUT key.

Model 2520 Pulsed Laser Diode Test System Service Manual Performance Verification 1-11

Figure 1-3

Connections for current source verification tests

PREV

DISPLAY

NEXT

POWER

Model 2001 DMM

Input HI

Input LO

W

SENSE

4 WIRE

HI

INPUT

!

DCV ACV

REL TRIG

INFO LOCAL

DCI ACI W 2 W 4

STORE RECALL

CHAN SCAN

FILTER MATH

CONFIG MENU

2001 MULTIMETER

FREQ TEMP

RANGE

AUTO

RANGE

EXIT ENTER

F

INPUTS

R

LO

FRONT/REAR

CAL

2A 250V

AMPS

500V

PEAK

10 W Cable (SC-182)

Tie Shields

Together

20cm

10 to 15 W Resistor (500mA Range,

20 RN60 Type 300 W in Parallel)

1.2 to 1.6

W Resistor (5A Range,

10 RN60 Type 16 W in Parallel)

BIAS

Model 2520 Testhead

CURRENT

INPUT

DETECTOR 1 DETECTOR 2

!

ISOLATION FROM EARTH: 10V MAX.

HI CURRENT

OUTPUT

LO

!

CAT I

HI

VOLTAGE

SENSE

LO

CURRENT

OUTPUT HI

CURRENT

OUTPUT LO

Figure 1-4

Parallel resistor construction

Connecting

Cables

RN60

Resistors

2-Sided

Board

Solder

CU Tape

Solder

Remove

Copper Strip

1-12 Performance Verification Model 2520 Pulsed Laser Diode Test System Service Manual

Figure 1-5

Resistor mounting and connections

Resistor Edge

View 0.5in

2

Maximum Loop

Area Resistors

Board

9. Calculate the current using the voltage value and characterized resistance value:

I = V/R. Recalculate reading limits from these values, then verify that the current is within those limits.

10. Replace the 10 Ω to 15 Ω resistor with the characterized 1.2

Ω to 1.6

Ω resistor.

11. Repeat steps 5 through 9 for the 5A range using the 1A value shown in

Table 1-3

12. For pulse mode verification, change connections as shown in

Figure 1-6 , then

repeat the above procedure. for the pulse mode.

Model 2520 Pulsed Laser Diode Test System Service Manual Performance Verification 1-13

Figure 1-6

Connections for current source pulse verification tests

10 W Cable (SC-182)

Tie Shields

Together

20cm

Model 2520 Testhead

10 to 15 W Resistor (500mA Range,

20 RN60 Type 300 W in Parallel)

1.2 to 1.6

W Resistor (5A Range,

10 RN60 Type 16 W in Parallel)

BIAS

CURRENT

INPUT

HI

CURRENT

OUTPUT

LO

DETECTOR 1 DETECTOR 2

!

ISOLATION FROM EARTH: 10V MAX.

!

CAT I

HI

VOLTAGE

SENSE

LO

BNC Cables VOLTAGE

SENSE Inputs

CURRENT

OUTPUTS

Table 1-3

Current source verification limits

Model 2520 range

500mA

00 5A

Test resistance

10 to 15 Ω

1

1.2 to 1.6

Ω 2

Output current

500.000mA

00 1.0000A

Output current limits*

(1 year, 18°C to 28°C)

498.55mA to 501.45mA

0.9935 to 1.0065A

*Nominal values. Recalculate limits from characterized resistance and measured voltage: I = V/R.

1

2

20 RN60 type 300 Ω in parallel.

10 RN60 type 16 Ω in parallel.

1-14 Performance Verification Model 2520 Pulsed Laser Diode Test System Service Manual

Current measurement accuracy

Follow the steps below to verify that Model 2520 detector current measurement accuracy is within specified limits. This test involves applying currents and verifying that

Model 2520 current readings are within required limits.

1. With the power off, connect the 2k Ω resistor and DMM to the testhead

DETECTOR 1 jack, as shown in Figure 1-7

. (See Figure 1-4

and Figure 1-5

for parallel resistor construction.)

2. Turn on the Model 2520 and DMM, and allow them to warm up for a minimum of one hour.

3. Select the DMM DC volts function, and enable auto-range.

Figure 1-7

Connections for DETECTOR 1 current measurement verification tests

PREV

DISPLAY

NEXT

POWER

Input HI

Model 2001 DMM

Ω

SENSE

4 WIRE

HI

INPUT

350V

PEAK

!

1100V

PEAK

2001 MULTIMETER

DCV ACV DCI ACI

Ω

2

Ω

4

REL TRIG

INFO LOCAL

STORE RECALL FILTER MATH

CHAN SCAN CONFIG MENU

FREQ TEMP

EXIT ENTER

RANGE

AUTO

RANGE

INPUTS

F R

FRONT/REAR

LO

2A 250V

AMPS

CAL

500V

PEAK

Input LO

Center

Conductor

Resistor

(See Text)

Inner

Shield

BIAS

Model 2520 Testhead

CURRENT

INPUT

DETECTOR 1 DETECTOR 2

!

ISOLATION FROM EARTH: 10V MAX.

DETECTOR 1

HI

CURRENT

OUTPUT

LO

!

CAT I

HI

VOLTAGE

SENSE

LO

4. Restore front panel (BENCH) defaults as outlined previously in

“Restoring factory defaults” on page 1-6 .

5. Press the DETECTOR 1 I

PD

RANGE key.

key, then select the Model 2520 10mA range with the

6. Press the DETECTOR 1 VB key, then press the EDIT key, and set the voltage bias source value to +20.000V.

7. Turn on the Model 2520 outputs by pressing the ON/OFF OUTPUT key.

8. Press the TRIG key. Note the DMM voltage reading, then turn off the outputs by pressing the ON/OFF OUTPUT key.

9. Calculate the current from the DMM voltage reading and characterized resistance value: I = V/R.

10. Calculate reading limits based on the current and Model 2520 specifications, then verify that the Model 2520 DETECTOR 1 current reading is within the limits.

11. Repeat steps 5 through 10 for the 20mA, 50mA, and 100mA ranges. Be sure to use the correct test resistor for each range.

Model 2520 Pulsed Laser Diode Test System Service Manual Performance Verification 1-15

12. After verifying all ranges for DETECTOR 1, repeat the entire procedure for

DETECTOR 2. (Connect the calibrator to the TESTHEAD DETECTOR 2 jack, and select that channel by pressing DETECTOR 2 I connections.)

PD

. See Figure 1-8 for

Table 1-4

Current measurement verification limits

Model 2520 range

0 10mA

0 20mA

0 50mA

100mA

Test resistor

00 2k Ω 1

00 1k Ω 2

0 400 Ω 3

0 200 Ω 4

Reading limits*

(1 year, 18°C to 28°C)

0 9.950 to 10.050mA

19.875 to 20.125mA

49.760 to 50.240mA

99.53

to 100.47mA

*Nominal values. Recalculate limits from characterized resistance and

1 measured voltage: I = V/R.

RN60 type 2k Ω .

2 2 RN60 type 2k Ω in parallel.

3

5 RN60 type 2k Ω in parallel.

4 10 RN60 type 2k Ω in parallel.

Figure 1-8

Connections for DETECTOR 2 current measurement verification tests

PREV

DISPLAY

NEXT

POWER

Input HI

Model 2001 DMM

Ω

SENSE

4 WIRE

HI

INPUT

350V

PEAK

!

1100V

PEAK

2001 MULTIMETER

DCV ACV DCI ACI

Ω

2

Ω

4

REL TRIG

INFO LOCAL

STORE RECALL FILTER MATH

CHAN SCAN CONFIG MENU

FREQ TEMP

EXIT ENTER

RANGE

AUTO

RANGE

F

INPUTS

LO

R

FRONT/REAR

CAL

2A 250V

AMPS

500V

PEAK

Input LO

Center

Conductor

Resistor

(See Text)

Inner

Shield

Model 2520 Testhead

BIAS

CURRENT

INPUT

DETECTOR 1 DETECTOR 2

!

ISOLATION FROM EARTH: 10V MAX.

HI

CURRENT

OUTPUT

LO

HI

VOLTAGE

SENSE

LO

DETECTOR 2

!

CAT I

1-16 Performance Verification Model 2520 Pulsed Laser Diode Test System Service Manual

Voltage bias source accuracy

Follow the steps below to verify that Model 2520 detector voltage bias source accuracy is within specified limits. This test involves setting the bias voltages to specific values and measuring the voltages with a DMM.

1. With the power off, connect the digital multimeter to the Model 2520 testhead

DETECTOR 1 jack, as shown in Figure 1-9

.

2. Turn on the Model 2520 and DMM, and allow them to warm up for a minimum of one hour.

3. Restore BENCH defaults as covered previously in “Restoring factory defaults” on page 1-6

.

4. Select the DMM DC volts measuring function, and choose auto-range.

Figure 1-9

Connections for DETECTOR 1 voltage bias source verification tests

PREV

DISPLAY

NEXT

POWER

Model 2001 DMM

Input HI

Ω

SENSE

4 WIRE

HI

INPUT

Center

Conductor

350V

PEAK

!

1100V

PEAK

2001 MULTIMETER

DCV ACV DCI ACI

Ω

2

Ω

4

REL TRIG

INFO LOCAL

STORE RECALL FILTER MATH

CHAN SCAN CONFIG MENU

FREQ TEMP

EXIT ENTER

RANGE

AUTO

RANGE

INPUTS

F R

FRONT/REAR

LO

2A 250V

AMPS

CAL

500V

PEAK

Triax Cable

Inner Shield

Input LO

DETECTOR 1 DETECTOR 2

!

ISOLATION FROM EARTH: 10V MAX.

DETECTOR 1

Model 2520 Testhead

BIAS

CURRENT

INPUT

HI

CURRENT

OUTPUT

LO

!

CAT I

HI

VOLTAGE

SENSE

LO

5. Press the DETECTOR 1 V

B

key, press EDIT, then set the source voltage to

+20.000V using the EDIT and or numeric keys.

6. Press the ON/OFF OUTPUT key to turn on the outputs, then press TRIG.

7. Verify the DMM reading is within the following limits: 19.75 to 20.25V.

8. Press the ON/OFF OUTPUT key to turn off the outputs.

9. Repeats steps 5 through 8 for the DETECTOR 2 bias source (make connections to

the testhead DETECTOR 2 jack as shown in Figure 1-10 , and use the DETECTOR

2 V

B

key to set the output voltage).

Model 2520 Pulsed Laser Diode Test System Service Manual Performance Verification 1-17

Figure 1-10

Connections for DETECTOR 2 voltage bias source verification tests

PREV

DISPLAY

NEXT

POWER

Model 2001 DMM

Input HI

Ω

SENSE

4 WIRE

HI

INPUT

350V

PEAK

!

1100V

PEAK

2001 MULTIMETER

DCV ACV DCI ACI

Ω

2

Ω

4

REL TRIG

INFO LOCAL

STORE RECALL FILTER MATH

CHAN SCAN CONFIG MENU

FREQ TEMP

EXIT ENTER

RANGE

AUTO

RANGE

INPUTS

LO

F R

FRONT/REAR

CAL

2A 250V

AMPS

500V

PEAK

Center

Conductor

Triax Cable

Inner Shield

Input LO

Model 2520 Testhead

BIAS

CURRENT

INPUT

DETECTOR 1 DETECTOR 2

!

ISOLATION FROM EARTH: 10V MAX.

DETECTOR 2

HI

CURRENT

OUTPUT

LO

!

CAT I

HI

VOLTAGE

SENSE

LO

2

Calibration

2-2 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

Introduction

Use the procedures in this section to calibrate the Model 2520 Pulsed Laser Diode Test

System. These procedures require accurate test equipment to supply and measure precise

DC currents and voltages. Calibration can be performed either from the front panel or by sending SCPI calibration commands over the IEEE-488 bus or RS-232 port with the aid of a computer.

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-3

WARNING While the Model 2520 does not incorporate a laser, it is designed to operate (power) laser diode devices. Read all safety precautions listed at the beginning of the Model 2520 User’s Manual. The following safety practices must be used to protect operators and other users of this product from potential exposure to laser radiation:

• Operators must be protected from radiation and electrical hazards at all times.

• The installer must comply with all applicable laws and regulations on laser safety. This requirement includes warning signs and operator training.

• The interlock is required for safe operation. The test fixtures must ensure that the interlock circuit is disabled (source outputs inhibited) so that an operator is not exposed to any radiation. The test fixture interlock must not be defeated.

• The testhead key control must be used to prevent operation unless authorized by the responsible body. This requirement must be part of the facilities administrative controls for laser safety.

Outputs cannot be turned on with the key removed.

• When servicing the test system, any required personnel protection equipment (e.g. laser safety goggles) must be provided by the customer’s responsible body.

• The customer’s laser safety officer (LSO) must review and approve all installations before they are put into operation. Any safety concerns must be immediately reported to the customer’s

LSO.

• If at any time, the indicators provided on the testhead for

INTERLOCK STATUS or LASER POWER ON should fail to light or properly indicate status, immediately contact a Keithley service representative for repair. Failure to do so may expose the user to hazards without proper warnings. See “Interlock status indicator test sequence” in Section 9 of the User’s manual for details on testing the indicator lights.

• Maximum isolation from earth ground is 10V. Exceeding this value may result in a shock hazard.

• When making connections, do not leave any exposed connections.

Ensure that all external circuits are properly insulated.

2-4 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

Environmental conditions

Temperature and relative humidity

Conduct the calibration procedures at an ambient temperature of 18-28°C (65-82°F) with relative humidity of less than 70% unless otherwise noted.

Warm-up period

Allow the Model 2520 to warm up for a minimum of one hour before performing calibration.

If the instrument has been subjected to temperature extremes (those outside the ranges stated above), allow additional time for the instrument’s internal temperature to stabilize.

Typically, allow one extra hour to stabilize a unit that is 10°C (18°F) outside the specified temperature range.

Also, allow the test equipment to warm up for the minimum time specified by the manufacturer.

Line power

The Model 2520 requires a line voltage of 100V to 240V at line frequency of 50 or 60Hz.

The instrument must be calibrated while operating from a line voltage within this range.

Calibration considerations

When performing the calibration procedures:

• Make sure that the test equipment is properly warmed up and connected to the

Model 2520 input or output terminals as required.

• Allow signals to settle before calibrating each point.

• Do not connect test equipment to the Model 2520 through a scanner or other switching equipment.

• If an error occurs during calibration, the Model 2520 will generate an appropriate error message. See Appendix B for more information.

WARNING The maximum common-mode voltage (voltage between LO and chassis ground) is ±10V DC. Exceeding this value may cause a shock hazard.

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-5

Calibration cycle

Perform calibration at least once a year to ensure the unit meets or exceeds its specifications.

Recommended calibration equipment

Table 2-1 lists the recommended equipment for the calibration procedures. You can use

alternate equipment as long that equipment has specifications at least as good as those listed in the table. For optimum calibration accuracy, test equipment specifications should be at least four times better than corresponding Model 2520 specifications.

Table 2-1

Recommended calibration equipment

Description

Calibrator

Digital

Multimeter

Manufacturer/Model Specifications

Fluke 5700A 1 DC Voltage: 5V:

10V:

Keithley 2001 2 DC Voltage: 20V:

DC Current: 2mA

20mA

200mA

±5ppm

±5ppm

±22ppm

±320ppm

±320ppm

±320ppm

Resistors 3

Resistance: 20 Ω

200 Ω

2k Ω

1.2 to 1.6

Ω , 2W, ±5% 4

10 to 15 Ω , 2W, ±5%

10 Ω , 0.5W, ±1%

10 0Ω , 0.5W, ±1%

200 Ω , 2W, ±1%

4

400 Ω , 1W, ±1%

1k Ω , 0.5W, ±1%

2k Ω , 0.25W, ±1%

±59ppm

±43ppm

±37ppm

Temperature coefficient =

20ppm/°C for all resistors.

1. 90-day accuracy specifications of lowest usable range for specified output.

2. 90-day full-range accuracy specifications.

3. Characterize resistors to within ±100ppm using 4-wire ohms function of digital multimeter before use.

4. Use only non-inductive metal film or bulk metal resistors.

Resistor characterization

The precision resistors listed in Table 2-1

should be characterized to within ±100ppm using the 4-wire ohms function of the digital multimeter before use. Use the characterized values when performing the calibration procedure.

2-6 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

Calibration menus

Table 2-2 summarizes the main calibration menu selections. To enter the calibration

menu, press the MENU key, select CAL, then press ENTER. Use the EDIT keys to move the cursor and scroll through menu selections.

Press ENTER to select a MENU item.

Table 2-2

Calibration menu

Menu selection Description

UNLOCK

EXECUTE

VIEW-DATES

SAVE

Unlock calibration using password (default: 002520).

Execute calibration steps for present range.

View calibration dates.

Save calibration constants.

LOCK Lock out calibration.

CHANGE-PASSWORD Change calibration password.

Table 2-3 summarizes the calibration execute menu. Each of these functions is covered in

detail below.

Table 2-3

Calibration execution menu

Menu selection

VL

IL

COMPLIANCE

PULS_LOW

Ipd1

Vb1

Ipd2

Vb2

Function calibrated

Laser voltage measure

Laser current source

Laser source compliance

Laser source pulse low

Detector 1 current measure

Detector 1 voltage bias source

Detector 2 current measure

Detector 2 voltage bias source

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-7

Unlocking calibration

Before performing calibration, you must first unlock calibration by entering or sending the calibration password as explained in the following paragraphs.

Unlocking calibration from the front panel

1. Press the MENU key, then choose CAL, and press ENTER. The instrument will display the following:

CALIBRATION

UNLOCK EXECUTE VIEW-DATES 䊳

SAVE LOCK CHANGE-PASSWORD

2. Select UNLOCK, then press ENTER. The instrument will display the following:

PASSWORD:

Use , 䊳 , , , ENTER or EXIT.

3. Use the EDIT and keys to select the letter or number, and use the EDIT and 䊳 arrow keys to choose the position. (Press for letters; for numbers.) Enter the present password on the display. (Front panel default: 002520.)

4. Once the correct password is displayed, press the ENTER key. You can then proceed with the calibration procedure.

Unlocking calibration by remote

To unlock calibration via remote, send the following command:

:CAL:PROT:CODE '<password>'

For example, the following command uses the default password:

:CAL:PROT:CODE 'KI002520'

2-8 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

Changing the password

The default password (002520) may be changed from the front panel or via remote, as discussed below.

Changing the password from the front panel

Follow the steps below to change the password from the front panel:

1. Press the MENU key, choose CAL, and press ENTER. The instrument will display the following:

CALIBRATION

UNLOCK EXECUTE VIEW-DATES 䊳

SAVE LOCK CHANGE-PASSWORD

2. Select UNLOCK, then enter the password. (Default: 002520.)

3. Select CHANGE-PASSWORD, and then press ENTER. The instrument will display the following:

New Pwd: 002520

Use , 䊳 , , , ENTER or EXIT.

4. Using the EDIT keys, enter the new password on the display.

5. Once the desired password is displayed, press the ENTER key to store the new password.

Changing the password by remote

To change the calibration password by remote, first send the present password, and then send the new password. For example, the following command sequence changes the password from the 'KI002520' remote default to 'KICAL':

:CAL:PROT:CODE 'KI002520'

:CAL:PROT:CODE 'KICAL'

You can use any combination of letters and numbers up to a maximum of eight characters.

NOTE If you change the first two characters of the password to something other than

“KI”, you will not be able to unlock calibration from the front panel.

Resetting the calibration password

If you lose the calibration password, you can unlock calibration by shorting together the

CAL pads, which are located on the display board. Doing so will also reset the password to the factory default (002520, front panel; KI002520, remote).

See Section 5 for details on disassembling the unit to access the CAL pads. Refer to the display board component layout drawing at the end of Section 6 for the location of the

CAL pads.

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-9

Viewing calibration dates and calibration count

When calibration is locked, only the UNLOCK and VIEW-DATES selections will be accessible in the calibration menu. To view calibration dates and calibration count at any time:

1. From normal display, press MENU, select CAL, and then press ENTER. The unit will display the following:

CALIBRATION

UNLOCK EXECUTE VIEW-DATES 䊳

2. Select VIEW-DATES, and then press ENTER. The Model 2520 will display the next and last calibration dates and the calibration count as in the following example:

NEXT CAL: 07/15/2002

Last cal: 07/15/2001 Count: 0001

Calibration errors

The Model 2520 checks for errors after each calibration step, minimizing the possibility that improper calibration may occur due to operator error.

Front panel error reporting

If an error is detected during calibration, the instrument will display an appropriate error message (see Appendix B). The unit will then prompt you to repeat the calibration step that caused the error.

Remote error reporting

You can detect errors while in remote by testing the state of EAV (Error Available) bit

(bit 2) in the status byte. (Use the *STB? query to request the status byte.) Query the instrument for the type of error by using the :SYST:ERR? query. The Model 2520 will respond with the error number and a text message describing the nature of the error. See

Appendix B for details.

Aborting calibration steps

To abort a calibration step from the front panel, press the EXIT key. To abort a calibration step via remote, send the :ABORt command.

2-10 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

Testhead connections

The Model 2520 mainframe must be connected to the testhead in order to perform

calibration. Using Figure 2-1

as a guide, make testhead connections as follows:

CAUTION Make sure power is turned off before making connections.

• Connect mainframe TESTHEAD CONN 1 to testhead MAINFRAME CONN 1.

• Connect mainframe TESTHEAD CONN 2 to testhead MAINFRAME CONN 2.

• Short pins 1 and 9 of the REMOTE INTERLOCK connector. Insert the key in the

KEY INTERLOCK and rotate to the ENABLED position to enable operation.

WARNING Shorting interlock connectors will disable the interlock. Use caution to avoid live contacts when performing calibration.

NOTE Both interlocks must be enabled to perform calibration.

Figure 2-1

Testhead connections

Model 2520 Mainframe

WARNING:

NO INTERNAL OPERATOR SERVICABLE PARTS, SERVICE BY QUALIFIED PERSONNEL ONLY.

MADE IN

U.S.A.

CAT I

IEEE-488

(CHANGE IEEE ADDRESS

WITH FRONT PANEL MENU)

PULSE

SYNC

OUT

!

DIGITAL I/O

TRIGGER LINK

RS-232

TESTHEAD

CONN 1

!

TESTHEAD

CONN 2

!

LINE FUSE

SLOWBLOW

1.6A, 250V

LINE RATING

100-240VAC

50, 60Hz

140VA MAX.

CAUTION:

FOR CONTINUED PROTECTION AGAINST FIRE HAZARD, REPLACE FUSE WITH SAME TYPE AND RATING.

Model 2520 Testhead

!

BOTH INTERLOCKS MUST BE ENABLED TO OPERATE

DISABLED

(PULL TO

REMOVE)

KEY

INTERLOCK

1

REMOTE

INTERLOCK

DISABLED

9

ENABLED

GREEN=ENABLED

RED=DISABLED

INTERLOCK

STATUS

ENABLED

LASER

POWER

ON

MAINFRAME

CONN 2

MAINFRAME

CONN 1

CONN 2 Cable

CONN 1 Cable

Front panel calibration

The front panel calibration procedure described below calibrates all functions. Note that each function and range is separately calibrated, and the procedure must be performed in the order shown.

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-11

Step 1: Prepare the Model 2520 for calibration

1. Turn on the Model 2520 and the calibration equipment, and allow them to warm up for a minimum of one hour before performing calibration.

2. Press the MENU key, choose CAL, and press ENTER. Select UNLOCK, and then press ENTER. The instrument will display the following:

PASSWORD:

Use , 䊳 , , , ENTER or EXIT.

3. Use the EDIT and keys to select the letter or number, and use the and 䊳 arrow keys to choose the position. (Press EDIT for letters; for numbers.) Enter the present password on the display. (Front panel default: 002520.)

4. Press ENTER to complete the process.

5. Press EXIT to return to normal display.

Step 2: Voltage measurement calibration

Follow the steps below to calibrate both voltage measurement ranges.

Table 2-4

summarizes calibration ranges and voltages.

1. From normal display, press the Model 2520 LASER V

L range using the RANGE key.

key, then select the 10V

2. Press the MENU key, select CAL, then press ENTER.

3. Select EXECUTE, then press ENTER to enter the CAL EXECUTION menu.

4. Select VL, then press ENTER. The unit displays the following:

VL-CAL

Remove all inputs

5. Make sure all signal cables are disconnected from the testhead, then press ENTER.

The instrument will display:

VL-CAL

Connect Calibrator HI to V-sense 䊳

LO and set it to -10.000V

Table 2-4

Voltage measurement calibration values

Voltage range

5V

10V

Calibration voltage

-5.0000V

-10.0000V

2-12 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

6. Connect the calibrator to the Model 2520 testhead VOLTAGE SENSE jacks, as shown in

Figure 2-2

. (Connect calibrator HI to VOLTAGE SENSE LO; connect calibrator LO to VOLTAGE SENSE HI.)

7. Turn on the calibrator output, set the calibrator voltage to -10.000V, then press

ENTER. The unit will prompt you as follows:

VL-CAL

Switch HI and LO connections

8. Switch the HI and LO calibrator connections, then press ENTER.

9. Press EXIT to return to normal display.

10. Press the LASER V

L

key to make sure the laser volts mode is selected.

11. Press the RANGE key to select the 5V range.

12. Repeat steps 2 through 9 for the 5V range. Be sure to set the calibrator output to

-5.000V as shown in Table 2-4 .

Figure 2-2

Voltage measurement calibration connections

Calibrator (Output DC Voltage)

Model 2520 Testhead

Output

HI

HI CURRENT

OUTPUT

LO

BIAS

CURRENT

INPUT

!

CAT I

DETECTOR 1 DETECTOR 2

!

ISOLATION FROM EARTH: 10V MAX.

VOLTAGE

SENSE HI

HI

VOLTAGE

SENSE

LO

VOLTAGE

SENSE LO

BNC Cables

Output LO

Step 3: Current source calibration

Follow the steps below to calibrate the current source. Table 2-5

summarizes calibration resistors.

1. From normal display, press the Model 2520 LASER V

L

10V range using the RANGE key.

key, then set the range to

2. Press the LASER I

L

key, press the EDIT key, then set the source to the 500mA range using the RANGE key.

3. Press the MENU key, select CAL, then press ENTER.

4. Select EXECUTE, then press ENTER to enter the calibration menu.

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-13

5. Select IL, then press ENTER. The instrument will prompt for the resistor:

RES VALUE: +15.000

Use , 䊳 , , , ENTER or EXIT.

Table 2-5

Current source calibration values

Current source range Calibration resistor

500mA

5A

10 to 15 Ω

1.2 to 1.6

Ω

6. Enter the measured value of the 10 to 15 Ω resistor, then press ENTER. The unit displays the following:

IL-CAL

Connect Calibration Resistor to 䊳

Pulse Sense and Pulse Source

7. Connect the 10 to 15 Ω resistor to the Model 2520 testhead VOLTAGE SENSE and

CURRENT OUTPUT jacks, as shown in

Figure 2-3 .

8. Press ENTER to complete calibration of the present range.

9. Press EXIT to return to normal display.

10. Press LASER I range.

L

, then EDIT, then use the RANGE key to select the 5A current

11. Press LASER V selected.

L

, then use the RANGE key to make sure the 10V range is

12. Disconnect the 10 to 15 Ω resistor, then connect the 1.2 to 1.6

Ω resistor in its place

( Figure 2-3

).

13. Repeat steps 3 to 9 for the 5A range using the 1.2 to 1.6¾ resistor instead of the

10 to 15¾ resistor.

Figure 2-3

Current source calibration connections

Model 2520 Testhead

10 to 15 Ω Resistor

(500mA Range)

1.2 to 1.6

Ω Resistor

(5A Range)

BIAS

CURRENT

INPUT

DETECTOR 1 DETECTOR 2

!

ISOLATION FROM EARTH: 10V MAX.

HI

CURRENT

OUTPUT

LO

!

CAT I

HI

VOLTAGE

SENSE

LO

CURRENT OUTPUT LO

CURRENT OUTPUT HI

VOLTAGE

SENSE HI

VOLTAGE

SENSE LO

2-14 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

Step 4: Pulse low calibration

Follow the steps below to calibrate current source pulse low.

Table 2-6 summarizes

calibration currents and test resistance values.

1. Connect DMM and 100 Ω resistor to the Model 2520 testhead CURRENT

OUTPUT jacks, as shown in

Figure 2-4 .

2. Select the DMM DC volts function, and enable auto-range.

3. Press the LASER I

L

key, press the EDIT key, then set the source to the 500mA range using the RANGE key.

4. Press the MENU key, select CAL, then press ENTER.

5. Select EXECUTE, then press ENTER to enter the calibration menu.

6. Select PULS_LOW, then press ENTER. The unit displays:

Pulse Low CAL

Press ENTER to Output +15.000mA

7. Press ENTER. The unit displays:

DMM RDG: +15.000mA

Use , 䊳 , , , ENTER or EXIT.

8. Note the DMM voltage reading, then calculate the current from the voltage and actual resistance value: I = V/R.

9. Adjust the display to agree with the calculated current, then press ENTER. The unit displays:

Pulse Low CAL

Press ENTER to Output +01.500mA

10. Press ENTER. The unit displays:

DMM RDG: +01.500mA

Use , 䊳 , , , ENTER or EXIT.

11. Again, note the DMM voltage reading, then calculate the current from the voltage and actual resistance value: I = V/R.

Table 2-6

Pulse low calibration values

Current source range Calibration values

500mA

5A

15mA, 1.5mA

150mA, 15mA

Calibration resistance

100 Ω

10 Ω

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-15

12. Adjust the display to agree with the calculated, then press ENTER. The unit displays the following:

Pulse Low CAL

Press ENTER to Output +15.000mA

13. Press ENTER. The unit displays:

DMM RDG: +15.000mA

Use , 䊳 , , , ENTER or EXIT.

14. Note the DMM voltage reading, then calculate the current from the voltage and actual resistance value: I = V/R.

15. Adjust the display to agree with the calculated, then press ENTER. The unit displays:

Pulse Low CAL

Press ENTER to Output +01.500mA

16. Press ENTER. The unit displays:

DMM RDG: +01.500mA

Use , 䊳 , , , ENTER or EXIT.

17. Note the DMM voltage reading, then calculate the current from the voltage and actual resistance value: I = V/R.

18. Adjust the display to agree with the calculated, then press ENTER.

19. Press EXIT to return to normal display.

20. Disconnect the 100 Ω resistor, and connect the 10 Ω resistor in its place

( Figure 2-4

).

21. Press LASER I range.

L

, then EDIT, then use the RANGE key to select the 5A current

22. Repeat steps 5 through 19 for the 5A range.

Figure 2-4

Pulse low calibration connections

PREV

DISPLAY

NEXT

POWER

Input HI

Model 2001 DMM

Ω

SENSE

4 WIRE

HI

INPUT

350V

PEAK

!

1100V

PEAK

2001 MULTIMETER

DCV ACV DCI ACI

Ω

2

Ω

4

REL TRIG

INFO LOCAL

STORE RECALL FILTER MATH

CHAN SCAN CONFIG MENU

FREQ TEMP

EXIT ENTER

RANGE

AUTO

RANGE

INPUTS

F R

FRONT/REAR

LO

2A 250V

AMPS

CAL

500V

PEAK

Input LO

10 Ω or 100 Ω

Resistor

(See Text)

Model 2520 Testhead

HI

CURRENT

OUTPUT

LO

BIAS

CURRENT

INPUT

DETECTOR 1 DETECTOR 2

!

ISOLATION FROM EARTH: 10V MAX.

!

CAT I

HI

VOLTAGE

SENSE

LO

CURRENT

OUTPUT HI

CURRENT

OUTPUT LO

2-16 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

Step 5: Voltage bias source calibration

Follow the steps below to calibrate both bias voltage sources.

1. Connect the DMM to the Model 2520 testhead DETECTOR 1 and VOLTAGE

SENSE HI jacks, as shown in Figure 2-5

. (Be sure to connect DMM LO to the inner shield of the DETECTOR triax cable.)

2. Select the DMM DC volts function, and enable auto-range.

3. Press the MENU key, select CAL, then press ENTER.

4. Select EXECUTE, then press ENTER to enter the CAL EXECUTION menu.

5. Select Vb1, then press ENTER.

6. The instrument will prompt for -20V calibration:

Vbias 1 CAL

Press ENTER to Output -20.000 V

7. Press ENTER. The instrument will display the following message:

DMM RDG: -20.00000 V

Use , 䊳 , , , ENTER or EXIT.

8. Note the DMM voltage reading, then use the EDIT keys to adjust the Model 2520 display value to agree with that reading.

Figure 2-5

Detector 1 voltage bias source calibration connections

PREV

DISPLAY

NEXT

POWER

Model 2001 DMM

Ω

SENSE

4 WIRE

HI

INPUT

350V

PEAK

!

1100V

PEAK

2001 MULTIMETER

DCV ACV DCI ACI

Ω

2

Ω

4

REL TRIG

INFO LOCAL

STORE RECALL FILTER MATH

CHAN SCAN CONFIG MENU

FREQ TEMP

EXIT ENTER

RANGE

AUTO

RANGE

INPUTS

F R

FRONT/REAR

LO

2A 250V

AMPS

CAL

500V

PEAK

Input HI

Triax Cable

Inner Shield

Input LO

Model 2520 Testhead

BIAS

CURRENT

INPUT

DETECTOR 1 DETECTOR 2

!

ISOLATION FROM EARTH: 10V MAX.

DETECTOR 1 VOLTAGE

SENSE HI

HI

CURRENT

OUTPUT

LO

!

CAT I

HI

VOLTAGE

SENSE

LO

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-17

9. Press ENTER. The unit will prompt for the 0V calibration point:

Vbias 1 CAL

Press ENTER to Output +00.000 V

10. Press ENTER. The instrument will display the following message:

DMM RDG: +00.00000 V

Use , 䊳 , , , ENTER or EXIT.

11. Note the DMM voltage reading, then use the EDIT keys to adjust the Model 2520 display value to agree with the reading.

12. Press ENTER. The unit will display the prompt for the +20V calibration point:

Vbias 1 CAL

Press ENTER to Output +20.000 V

13. Press ENTER. The instrument will display the following message:

DMM RDG: +20.00000 V

Use , 䊳 , , , ENTER or EXIT.

14. Note the DMM voltage reading, then use the EDIT keys to adjust the Model 2520 display value to agree with the reading, and press ENTER.

15. Press EXIT to return to normal display.

16. Repeat steps 4 through 15 for the DETECTOR 2 bias voltage source. Make your connections to the testhead DETECTOR 2 jack (

Figure 2-6 ), and select Vb2 for

calibration.

Figure 2-6

Detector 2 voltage bias source calibration connections

PREV

DISPLAY

NEXT

POWER

Input HI

Model 2001 DMM

Ω

SENSE

4 WIRE

HI

INPUT

350V

PEAK

!

1100V

PEAK

2001 MULTIMETER

DCV ACV DCI ACI

Ω

2

Ω

4

REL TRIG

INFO LOCAL

STORE RECALL FILTER MATH

CHAN SCAN CONFIG MENU

FREQ TEMP

EXIT ENTER

RANGE

AUTO

RANGE

INPUTS

F R

FRONT/REAR

LO

2A 250V

AMPS

CAL

500V

PEAK

Triax Cable

Inner Shield

Input LO

Model 2520 Testhead

BIAS

CURRENT

INPUT

DETECTOR 1 DETECTOR 2

!

ISOLATION FROM EARTH: 10V MAX.

HI

CURRENT

OUTPUT

LO

!

CAT I

HI

VOLTAGE

SENSE

LO

DETECTOR 2 VOLTAGE

SENSE HI

2-18 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

Step 6: Current measurement calibration

Follow the steps below to calibrate all photodiode current measurement ranges.

Table 2-7

summarizes calibration ranges and resistors.

Table 2-7

Current measurement calibration values

Current range

10mA

20mA

50mA

100mA

Calibration resistor*

2k Ω

1k Ω

400 Ω

200 Ω

* Nominal values. Use measured values for procedure.

1. Select the DMM DC volts function, and enable auto-range. Temporarily short the ends of the DMM test leads together, then enable REL to null offsets.

2. Connect the 2k Ω resistor and the DMM to the Model 2520 testhead DETECTOR 1

jack, as shown in Figure 2-7

.

3. From normal display, press the Model 2520 DETECTOR 1 I

PD

10mA current range using the RANGE key.

key, then select the

4. Press the MENU key, select CAL, then press ENTER.

5. Select EXECUTE, then press ENTER to enter the CAL EXECUTION menu.

6. Select Ipd1, then press ENTER. The instrument will prompt for the resistor value:

RES VALUE: +2000.00

Use , 䊳 , , , ENTER or EXIT.

Figure 2-7

Detector 1 current measurement calibration connections

PREV

DISPLAY

NEXT

POWER

Model 2001 DMM

Input HI Center

Conductor

Ω

SENSE

4 WIRE

HI

INPUT

350V

PEAK

!

1100V

PEAK

2001 MULTIMETER

DCV ACV DCI ACI

Ω

2

Ω

4

REL TRIG

INFO LOCAL

STORE RECALL FILTER MATH

CHAN SCAN CONFIG MENU

FREQ TEMP

EXIT ENTER

RANGE

AUTO

RANGE

F

INPUTS

LO

R

FRONT/REAR

CAL

2A 250V

AMPS

500V

PEAK

Resistor

(See Text)

Inner

Shield

Input LO

Model 2520 Testhead

BIAS

CURRENT

INPUT

DETECTOR 1 DETECTOR 2

!

ISOLATION FROM EARTH: 10V MAX.

DETECTOR 1

HI

CURRENT

OUTPUT

LO

!

CAT I

HI

VOLTAGE

SENSE

LO

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-19

7. Press ENTER. The instrument will prompt for calibration with -20V:

Ipd 1 CAL

Press ENTER to Output -20.000 V

8. Press ENTER. The unit will display:

DMM RDG: -20.000 V

Use , 䊳 , , , ENTER or EXIT.

9. Use the EDIT keys to adjust the Model 2520 display value to agree with the DMM voltage reading.

10. Press ENTER. The instrument will prompt for 0V calibration:

Ipd 1 CAL

Press ENTER to Output +00.000 V

11. Press ENTER. The unit will display:

DMM RDG: +00.000 V

Use , 䊳 , , , ENTER or EXIT.

12. Use the EDIT keys to adjust the Model 2520 display value to agree with the DMM reading.

13. Press ENTER. The instrument will prompt for calibration with +20V:

Ipd 1 CAL

Press ENTER to Output +20.000 V

14. Press ENTER. The unit will display:

DMM RDG: +20.000 V

Use , 䊳 , , , ENTER or EXIT.

15. Use the EDIT keys to adjust the Model 2520 display value to agree with the DMM reading, then press ENTER.

16. Press EXIT to return to normal display.

17. Repeat steps 3 through 16 for the 20mA, 50mA, and 100mA ranges, using

Table 2-7

as a guide. Be sure to set the Model 2520 to the correct range using the

RANGE and keys, and use the correct resistor for each range.

18. Repeat steps 3 through 17 for the DETECTOR 2 measurement channel. Make calibrator connections to the testhead DETECTOR 2 jack (see

Figure 2-8 ).

Figure 2-8

Detector 2 current measurement calibration connections

Model 2001 DMM

Input

HI

Center

Conductor

Model 2520 Testhead

Ω

SENSE

4 WIRE

HI

INPUT

PREV

DISPLAY

NEXT

POWER

DCV ACV

REL TRIG

INFO LOCAL

350V

PEAK

!

1100V

PEAK

DCI ACI

Ω

2

Ω

4

STORE RECALL FILTER MATH

CHAN SCAN CONFIG MENU

2001 MULTIMETER

FREQ TEMP

EXIT ENTER

RANGE

AUTO

RANGE

F

INPUTS

LO

R

FRONT/REAR

CAL

2A 250V

AMPS

500V

PEAK

Resistor

(See Text)

Inner

Shield

Input LO

BIAS

CURRENT

INPUT

DETECTOR 1 DETECTOR 2

!

ISOLATION FROM EARTH: 10V MAX.

DETECTOR 2

HI

CURRENT

OUTPUT

LO

!

CAT I

HI

VOLTAGE

SENSE

LO

2-20 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

Step 7: Compliance calibration

Follow the steps below to calibrate compliance:

1. Connect the DMM to the CURRENT OUTPUT jacks, as shown in Figure 2-9

.

Select the DC volts function, and enable auto-range.

2. From normal display, press LASER I

L

3. Press the EDIT 䊳 : key.

, then press the EDIT key.

4. Select the 500mA key with the RANGE key.

5. Using the EDIT and 䊳 : keys and EDIT and keys, set the current source to

100.00mA.

6. Press the MENU key, select CAL, then press ENTER.

7. Select EXECUTE, then press ENTER to enter the CAL EXECUTION menu.

8. Select COMPLIANCE, then press ENTER. The unit displays the following:

Compliance CAL

Press ENTER to Output +10.500V

9. Press ENTER. The instrument will display:

DMM RDG: +10.500 V

Use , 䊳 , , , ENTER or EXIT.

10. Note the DMM reading, then adjust the Model 2520 display to agree with that value.

11. Press ENTER. The instrument will display:

DMM RDG: +03.000 V

Use , 䊳 , , , ENTER or EXIT.

12. Note the DMM reading, then adjust the Model 2520 display to agree with that value. Press ENTER to complete compliance calibration.

Figure 2-9

Compliance calibration connections

Model 2520 Testhead

PREV

DISPLAY

NEXT

POWER

Model 2001 DMM

Ω

SENSE

4 WIRE

HI

INPUT

350V

PEAK

!

1100V

PEAK

2001 MULTIMETER

DCV ACV DCI ACI

Ω

2

Ω

4

REL TRIG

INFO LOCAL

STORE RECALL FILTER MATH

CHAN SCAN CONFIG MENU

FREQ TEMP

EXIT ENTER

RANGE

AUTO

RANGE

INPUTS

F R

FRONT/REAR

LO

2A 250V

AMPS

CAL

500V

PEAK

Input HI

Input LO

HI

CURRENT

OUTPUT

LO

BIAS

CURRENT

INPUT

DETECTOR 1 DETECTOR 2

!

ISOLATION FROM EARTH: 10V MAX.

!

CAT I

HI

VOLTAGE

SENSE

LO

CURRENT

OUTPUT HI

CURRENT

OUTPUT LO

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-21

Step 8: Enter calibration dates and save calibration

NOTE For temporary calibration without saving new calibration constants, proceed to

Step 9: Lock out calibration.

1. From the CALIBRATION menu, select SAVE, and then press ENTER. The unit will prompt you for the calibration date:

CAL DATE: 08/15/2001

Use , 䊳 , , , ENTER or EXIT.

2. Using the EDIT keys, change the displayed date to today's date, and then press the

ENTER key. Press ENTER again to confirm the date.

3. The unit will then prompt for the calibration due date:

NEXT CAL: 08/15/2002

Use , 䊳 , , , ENTER or EXIT.

4. Set the calibration due date to the desired value, and then press ENTER. Press

ENTER again to confirm the date.

5. Once the calibration dates are entered, calibration is complete, and the following message will be displayed:

CALIBRATION COMPLETE

Press ENTER to save; EXIT to abort

6. Press ENTER to save the calibration data (or press EXIT to abort without saving calibration data.)

Step 9: Lock out calibration

From the CAL EXECUTION menu, select LOCK, and then press ENTER to lock out calibration. Press EXIT to return to normal display.

2-22 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

Remote calibration

Use the following procedure to perform remote calibration by sending SCPI commands over the IEEE-488 bus or RS-232 port. The remote commands and appropriate parameters are separately summarized for each step.

Remote calibration command summary

Table 2-8 summarizes only those remote calibration commands used in this section.

NOTE For a detailed description of all calibration commands and queries, refer to

Appendix B.

Table 2-8

Remote calibration command summary

Command

:CALibration

:PROTected

:CODE '<password>'

:CODE?

:SENSe[1] <NRf>

:SENSe2 <NRf>

:SENSe3 <NRf>

:SOURce[1] <NRf>

:PROTection <NRf>

:LOW <NRf>

:SOURce2 <NRf>

:SOURce3 <NRf>

:DATE <yyyy>,<mm>,<dd>

:NDUE <yyyy>,<mm>,<dd>

:SAVE

:LOCK

:DIAGnostic

:KEIThley

:FCON

:HI <b>

Description

Calibration subsystem.

Calibration commands protected by password.

Unlock calibration. (Default password: KI002520.)

Query password (if calibration is unlocked).

Calibrate active range of voltage measurement.

Calibrate active range of detector 1 current measurement.

Calibrate active range of detector 2 current measurement.

Calibrate active range of current source.

Calibrate voltage compliance.

Calibrate current source pulse low output level.

Calibrate detector 1 voltage bias source.

Calibrate detector 2 voltage bias source.

Program calibration year, month, day.

Program calibration due year, month, day.

Save calibration constants in EEPROM.

Lock out calibration.

Diagnostic subsystem.

:LO <b>

Internally connect VOLTAGE SENSE HI input to floating ground.

Internally connect VOLTAGE SENSE LO input to floating ground.

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-23

Remote calibration procedure

Step 1: Prepare the Model 2520 for calibration

1. With the power off, connect the Model 2520 to the controller IEEE-488 interface or RS-232 port using a shielded interface cable.

2. Turn on the Model 2520 and the test equipment, and allow them to warm up for a minimum of one hour before performing calibration.

3. If you are using the IEEE-488 interface, make sure the primary address of the

Model 2520 is the same as the address specified in the program you will be using to send commands. (Use the COMM key to access the IEEE-488 address.)

4. Send the following command to unlock calibration:

:CAL:PROT:CODE ‘KI002520’

2-24 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

Step 2: Voltage measurement calibration

Follow these steps to calibrate voltage measurements. Table 2-9

summarizes calibration voltages and commands.

1. Put the unit into the DC mode with this command:

:SOUR1:FUNC:SHAP DC

2. Send the following command to select the 10V range:

:SENS1:VOLT:RANG 10

3. Disconnect all signal cables from the testhead.

4. Send the following commands in order:

:DIAG:KEIT:FCON:HI ON

:DIAG:KEIT:FCON:LO ON

:SENS1:VOLT:POL NEG

:CAL:PROT:SENS1 0

:SENS1:VOLT:POL POS

:CAL:PROT:SENS1 0

:DIAG:KEIT:FCON:LO OFF

5. Connect the calibrator to the Model 2520 testhead VOLTAGE SENSE jacks, as shown in

Figure 2-2

.

6. Set the calibrator voltage output to -10.000V, and turn on its output.

7. Send the following command to calibrate the +10V point:

:CAL:PROT:SENS1 10

8. Reverse the calibrator HI and LO connections.

9. Send the following commands to calibrate the negative full-range voltage point:

:DIAG:KEIT:FCON:HI OFF

:DIAG:KEIT:FCON:LO ON

:SENS1:VOLT:POL NEG

:CAL:PROT:SENS1 -10

:DIAG:KEIT:FCON:LO OFF

10. Repeat steps 2 through 9 for the 5V range using Table 2-9 as a guide. Be sure to:

• Select the 5V range using the :SENS1:VOLT:RANG 5 command.

• Send the appropriate calibration voltage values with the :CAL:PROT:SENS1

<Voltage> command.

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-25

Table 2-9

Voltage measurement calibration voltages and commands

Voltage range Calibration voltages* Calibration commands

5V

10V

0

-5.00000V

+5.00000V

0

-10.0000V

+10.0000V

:SOURI:FUNC:SHAP DC

:SENS1:VOLT:RANG 5

:DIAG:KEIT:FCON:HI ON

:DIAG:KEIT:FCON:LO ON

:SENS1:VOLT:POL NEG

:CAL:PROT:SENS1 0

:SENS1:VOLT:POL POS

:CAL:PROT:SENS1 0

:DIAG:KEIT:FCON:LO OFF

:CAL:PROT:SENS1 5

:DIAG:KEIT:FCON:HI OFF

:DIAG:KEIT:FCON:LO ON

:SENS1:VOLT:POL NEG

:CAL:PROT:SENS1 -5

:DIAG:KEIT:FCON:LO OFF

:SOURI:FUNC:SHAP DC

:SENS1:VOLT:RANG 10

:DIAG:KEIT:FCON:HI ON

:DIAG:KEIT:FCON:LO ON

:SENS1:VOLT:POL NEG

:CAL:PROT:SENS1 0

:SENS1:VOLT:POL POS

:CAL:PROT:SENS1 0

:DIAG:KEIT:FCON:LO OFF

:CAL:PROT:SENS1 10

:DIAG:KEIT:FCON:HI OFF

:DIAG:KEIT:FCON:LO ON

:SENS1:VOLT:POL NEG

:CAL:PROT:SENS1 -10

:DIAG:KEIT:FCON:LO OFF

* Polarity reversed by switching calibrator connections. See procedure.

2-26 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

Step 3: Current source calibration

Follow these steps to calibrate the current source. Table 2-10 summarizes current source

calibration resistances and commands.

1. Send the following command to select the pulse mode:

:SOUR1:FUNC:SHAP PULS

2. Send the following commands to set source and measure polarities:

:SENS1:VOLT:POL POS

:SOUR1:CURR:POL POS

3. Connect the 10 to 15 Ω resistor to the Model 2520 testhead VOLTAGE SENSE and

CURRENT OUTPUT jacks, as shown in

Figure 2-3 .

4. Set the pulse transition to fast:

:SOUR1:PULS:TRAN:STAT OFF

5. Set ranges with these commands:

:SENS1:VOLT:RANG 10

:SOUR1:CURR:RANG 0.5

6. Send this command to turn on the source output:

:OUTP1 ON

7. Set the compliance DAC to full scale so that it does not affect the measurement:

:DIAG:KEIT:BITS:VDAC1 4095

8. Source 10% of full scale:

:SOUR1:CURR 0.05

9. Trigger a pulse:

:INIT

10. Send the following query to request the Model 2520 voltage measurement:

:SENS1:DATA?

11. Note the voltage reading returned by the Model 2520 in step 10, then calculate the actual sourced current as follows: I = V/R. Here, I is the actual sourced current, V is the returned Model 2520 voltage reading, and R is the actual resistance value.

12. Send the following calibration command using the current calculated in step 11:

:CAL:PROT:SOUR1 <Calculated_Current>

For example, if the resistance value is 14.02

Ω , and the returned voltage reading from step 10 is 0.6732V, the actual current is: I = 0.6732V/14.02

Ω = 0.048017A.

In this example, the calibration command is:

:CAL:PROT:SOUR1 0.048017

13. Send this command to source 90% of full scale current:

:SOUR1:CURR 0.45

14. Repeat steps 9 through 12.

15. Send this command to select the slow transition pulse:

:SOUR1:PULS:TRAN:STAT ON

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-27

Table 2-10

Remote current source calibration summary

Current range Calibration resistance 1 Calibration commands

N/A

500mA

5A

10 to 15 Ω

1.2 to 1.6

Ω

:SOUR1:FUNC:SHAP PULS

:SENS1:VOLT:POL POS

:SOUR1:CURR:POL POS

:SOUR1:PULS:TRAN:STAT ON | OFF 2

:SENS1:VOLT:RANG 10

:SOUR1:CURR:RANG 0.5

:OUTP1 ON

:DIAG:KEIT:BITS:VDAC1 4095

:SOUR1:CURR 0.05

:INIT

:SENS1:DATA?

:CAL:PROT:SOUR1 <Calculated_Current> 3

:SOUR1:CURR 0.45

:INIT

:SENS1:DATA?

:CAL:PROT:SOUR1 <Calculated_Current> 3

:OUTP1 OFF

:SOUR1:PULS:TRAN:STAT ON | OFF 2

:SENS1:VOLT:RANG 10

:SOUR1:CURR:RANG 5

:OUTP1 ON

:DIAG:KEIT:BITS:VDAC1 4095

:SOUR1:CURR 0.5

:INIT

:SENS1:DATA?

:CAL:PROT:SOUR1 <Calculated_Current> 3

:SOUR1:CURR 4.5

:INIT

:SENS1:DATA?

:CAL:PROT:SOUR1 <Calculated_Current> 3

:OUTP1 OFF

1. Use characterized resistance values.

2. Repeat steps for both fast and slow pulse transition. See procedure.

3. Calculate current from voltage measurement and actual resistance: I = V/R.

2-28 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

16. Repeat steps 5 through 14 to calibrate the slow transition pulse.

17. Repeat steps 3 through 16 for the 5A range with the following exceptions:

• Use the 1.2 to 1.6

Ω resistor.

• Select the 5A source range with this command:

:SOUR1:CURR:RANG 5

• Set the appropriate 10% (0.5) and 90% (4.5) of range values using this command:

:SOUR1:CURR <Current>

18. Send this command to turn off the output:

:OUTP1 OFF

Step 4: Pulse low calibration

Follow these steps to calibrate current source pulse low.

Table 2-11

summarizes calibration resistances and commands.

1. Connect the 100 Ω resistor and DMM to the Model 2520 testhead CURRENT

OUTPUT jacks, as shown in

Figure 2-4 .

2. Select the DMM DC volts function, and enable auto-range.

3. Put the unit into the pulse mode:

:SOUR1:FUNC:SHAP PULS

4. Send this command to turn on the source output:

:OUTP1 ON

5. Enable fast transition pulses:

:SOUR1:PULS:TRAN:STAT OFF

6. Send the following command to select the 500mA current range:

:SOUR1:CURR:RANG 0.5

7. Send this command to set the current to 15mA:

:SOUR1:CURR:LOW 15e-3

8. Note the DMM reading, then calculate the current from the voltage and actual resistance, adding a slight offset value: I = V/R + 90 μ A.

9. Send the calculated current value as the parameter for the following command:

:CAL:PROT:SOUR1:LOW <Calculated_current>

For example, if the current is 14.5mA, the correct command is:

:CAL:PROT:SOUR1:LOW 14.59e-3

10. Send this command to set the current to 1.5mA:

:SOUR1:CURR:LOW 1.5e-3

11. Note the DMM reading, then calculate the current from the voltage and actual resistance, subtracting a slight offset value: I = V/R -75 μ A.

12. Send the calculated current value as the parameter for the following command:

:CAL:PROT:SOUR1:LOW <Calculated_current>

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-29

13. Enable slow pulses:

:SOUR1:PULS:TRAN:STAT ON

14. Repeat steps 5 through 12.

15. Send this command to turn off the output:

:OUTP1 OFF

16. Disconnect the 100 Ω resistor, then connect the 10 Ω resistor in its place.

17. Repeat steps 3 through 15 for the 5A range with the following changes:

• Select the 5A range:

:SOUR1:CURR:RANG 5

• Use these commands to set the two low current values:

:SOUR1:CURR:LOW 0.15

:SOUR1:CURR:LOW 0.015

• Use 900µA and 750µA respectively as the offsets when calculating the

:CAL:PROT:SOUR1:LOW parameter.

Table 2-11

Remote pulse low calibration summary

Current range Calibration resistance 1

N/A

500mA

5A

100

10 Ω

Ω

Calibration commands

:SOUR1:FUNC:SHAP PULS

:OUTP1 ON

:SOUR1:PULS:TRAN:STAT OFF | ON 2

:SOUR1:CURR:RANG 0.5

:SOUR1:CURR:LOW 15e-3

:CAL:PROT:SOUR1:LOW <Current + 90 μ A>

:SOUR1:CURR:LOW 1.5e-3

:CAL:PROT:SOUR1:LOW <Current - 75 μ A>

:OUTP1 OFF

:OUTP1 ON

:SOUR1:PULS:TRAN:STAT OFF | ON 2

:SOUR1:CURR:RANG 5

:SOUR1:CURR:LOW 150e-3

:CAL:PROT:SOUR1:LOW <Current + 900 μ A>

:SOUR1:CURR:LOW 15e-3

:CAL:PROT:SOUR1:LOW <Current - 750 μ A>

:OUTP1 OFF

1. Use actual resistance values when calculating currents.

2. Repeat steps for both fast and slow pulses. See procedure.

2-30 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

Step 5: Voltage bias source calibration

Follow these steps to calibrate the two voltage bias sources.

Table 2-12

summarizes calibration voltages and commands.

1. Connect the DMM to the Model 2520 testhead DETECTOR 1 and VOLTAGE

SENSE HI jacks, as shown in Figure 2-5

.

2. Select the DMM DC voltage function, and enable auto-range.

3. Connect the VOLTAGE SENSE HI terminal to internal ground:

:DIAG:KEIT:FCON:HI ON

4. Send this command to turn on the output:

:OUTP1 ON

5. Send the following command to output +20V:

:SOUR2:VOLT 20

6. Note and record the DMM reading, and then send the negative of that value as the parameter for the following command:

:CAL:PROT:SOUR2 -<DMM_Reading>

7. Send the following command to output 0V:

:SOUR2:VOLT 0

8. Note and record the DMM reading, and then send the negative of that value as the parameter for the following command:

:CAL:PROT:SOUR2 -<DMM_Reading>

9. Send the following command to output -20V:

:SOUR2:VOLT -20

10. Note and record the DMM reading, and then send the negative of that value as the parameter for the following command:

:CAL:PROT:SOUR2 -<DMM_Reading>

11. Send this command to turn off the outputs:

:OUTP1 OFF

12. Disconnect VOLTAGE SENSE HI from ground:

:DIAG:KEIT:FCON:HI OFF

13. Repeat steps 3 through 12 for detector 2 using Table 2-12 as a guide. Be sure to:

• Connect the DMM to the testhead DETECTOR 2 and VOLTAGE SENSE HI jacks (

Figure 2-6 ).

• Send source values using the :SOUR3:VOLT command where appropriate.

• Calibrate each point using the :CAL:PROT:SOUR3 command.

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-31

Table 2-12

Remote voltage bias source calibration summary

Voltage bias channel Calibration voltages Calibration commands*

Detector 1

Detector 2

+20V

0V

-20V

+20V

0V

-20V

:DIAG:KEIT:FCON:HI ON

:OUTP1 ON

:SOUR2:VOLT 20

:CAL:PROT:SOUR2 -<DMM_Reading>

:SOUR2:VOLT 0

:CAL:PROT:SOUR2 -<DMM_Reading>

:SOUR2:VOLT -20

:CAL:PROT:SOUR2 -<DMM_Reading>

:OUTP1 OFF

:DIAG:KEIT:FCON:HI OFF

:DIAG:KEIT:FCON:HI ON

:OUTP1 ON

:SOUR3:VOLT 20

:CAL:PROT:SOUR3 -<DMM_Reading>

:SOUR3:VOLT 0

:CAL:PROT:SOUR3 -<DMM_Reading>

:SOUR3:VOLT -20

:CAL:PROT:SOUR3 -<DMM_Reading>

:OUTP1 OFF

:DIAG:KEIT:FCON:HI OFF

*Command parameter values are negative of the displayed DMM reading.

Step 6: Current measurement calibration

Follow these steps to calibrate current measurements for both photodiode detector channels.

Table 2-13

summarizes calibration currents and commands.

1. Select the DMM DC voltage function, and enable auto-range.

2. Temporarily short the ends of the DMM test leads together, and enable the REL mode to null offsets.

3. Connect the DMM and 2k Ω resistor to the Model 2520 testhead DETECTOR 1

jack, as shown in Figure 2-7

.

4. Send the following command to select the 10mA range:

:SENS2:CURR:RANG 10e-3

5. Put the unit into the DC mode:

:SOUR1:FUNC:SHAP DC

6. Select positive current measurement polarity:

:SENSE2:CURR:POL POS

2-32 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

7. Send this command to turn on the outputs:

:OUTP1 ON

8. Send the following command to output -20V:

:SOUR2:VOLT -20

9. Note the DMM voltage reading, then calculate the current from the characterized resistance value and DMM voltage reading: I = V/R

10. Send the following command to calibrate the negative full-range current point:

:CAL:PROT:SENS2 <Calculated_current>

11. Send the following command to output 0V:

:SOUR2:VOLT 0

12. Note the DMM voltage reading, then calculate the current from the characterized resistance value and DMM voltage reading: I = V/R

13. Send the following command to calibrate the zero range current point:

:CAL:PROT:SENS2 <Calculated_current>

14. Switch current measurement polarity to negative:

:SENSE2:CURR:POL NEG

15. Calibrate the negative zero range current point:

:CAL:PROT:SENS2 <Calculated_current>

16. Send the following command to output +20V:

:SOUR1:VOLT 20

17. Note the DMM voltage reading, then calculate the current from the characterized resistance value and DMM voltage reading: I = V/R

18. Send the following command to calibrate the positive full-range current point:

:CAL:PROT:SENS2 <Calculated_current>

Note that if the measured voltage is negative, the current will be negative.

19. Repeat steps 4 through 18 for the 20mA, 50mA, and 100mA ranges using

Table 2-13 as a guide. Be sure to:

• Select the appropriate range using the :SENS2:CURR:RANG <Range> command.

• Send the appropriate calibration current values with the :CAL:PROT:SENS2

<Current> command.

20. Turn off the outputs by sending:

:OUTP1 OFF

21. Repeat steps 3 through 20 for the other photodiode current measurement channel.

Be sure to:

• Connect the DMM and resistor to the testhead DETECTOR 2 jack

( Figure 2-8

).

• Use the :SOUR3:CURR:RANG command to select the correct range.

• Use the :CAL:PROT:SOUR3 command for each calibration point.

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-33

Table 2-13

Remote current measurement calibration currents and commands

Channel

Detector 1

Current range Test resistor*

10mA

20mA

50mA

2k Ω

1k Ω

400 Ω

Calibration currents*

-10mA

0mA

0mA

+10mA

-20mA

0mA

0mA

+20mA

-50mA

0mA

0mA

+50mA

Calibration commands*

:OUTP1 ON

:SENS2:CURR:RANG 10e-3

:SOUR1:FUNC:SHAP DC

:SENSE2:CURR:POL POS

:SOUR2:VOLT -20

:CAL:PROT:SENS2 <Current>

:SOUR2:VOLT 0

:CAL:PROT:SENS2 <Current>

:SENSE2:CURR:POL NEG

:CAL:PROT:SENS2 <Current>

:SOUR2:VOLT 20

:CAL:PROT:SENS2 <Current>

:SENS2:CURR:RANG 20e-3

:SOUR1:FUNC:SHAP DC

:SENSE2:CURR:POL POS

:SOUR2:VOLT -20

:CAL:PROT:SENS2 <Current>

:SOUR2:VOLT 0

:CAL:PROT:SENS2 <Current>

:SENSE2:CURR:POL NEG

:CAL:PROT:SENS2 <Current>

:SOUR2:VOLT 20

:CAL:PROT:SENS2 <Current>

:SENS2:CURR:RANG 50e-3

:SOUR1:FUNC:SHAP DC

:SENSE2:CURR:POL POS

:SOUR2:VOLT -20

:CAL:PROT:SENS2 <Current>

:SOUR2:VOLT 0

:CAL:PROT:SENS2 <Current>

:SENSE2:CURR:POL NEG

:CAL:PROT:SENS2 <Current>

:SOUR2:VOLT 20

:CAL:PROT:SENS2 <Current>

* Nominal values shown. Calculate actual current from characterized resistance and DMM voltage reading: I = V/R.

2-34 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

Table 2-13 (continued)

Remote current measurement calibration currents and commands

Channel

Detector 1

Detector 2

Current range Test resistor*

100mA

10mA

20mA

200 Ω

2k

1k

Ω

Ω

Calibration currents*

-100mA

0mA

0mA

+100mA

-10mA

0mA

0mA

+10mA

-20mA

0mA

0mA

+20mA

Calibration commands*

:SENS2:CURR:RANG 100e-3

:SOUR1:FUNC:SHAP DC

:SENSE2:CURR:POL POS

:SOUR2:VOLT -20

:CAL:PROT:SENS2 <Current>

:SOUR2:VOLT 0

:CAL:PROT:SENS2 <Current>

:SENSE2:CURR:POL NEG

:CAL:PROT:SENS2 <Current>

:SOUR2:VOLT 20

:CAL:PROT:SENS2 <Current>

:OUTP1 OFF

:OUTP1 ON

:SENS3:CURR:RANG 10e-3

:SOUR1:FUNC:SHAP DC

:SENSE3:CURR:POL POS

:SOUR3:VOLT -20

:CAL:PROT:SENS3 <Current>

:SOUR3:VOLT 0

:CAL:PROT:SENS3 <Current>

:SENSE3:CURR:POL NEG

:CAL:PROT:SENS3 <Current>

:SOUR3:VOLT 20

:CAL:PROT:SENS3 <Current>

:SENS3:CURR:RANG 20e-3

:SOUR1:FUNC:SHAP DC

:SENSE3:CURR:POL POS

:SOUR3:VOLT -20

:CAL:PROT:SENS3 <Current>

:SOUR3:VOLT 0

:CAL:PROT:SENS3 <Current>

:SENSE3:CURR:POL NEG

:CAL:PROT:SENS3 <Current>

:SOUR3:VOLT 20

:CAL:PROT:SENS3 <Current>

* Nominal values shown. Calculate actual current from characterized resistance and DMM voltage reading: I = V/R.

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-35

Table 2-13 (continued)

Remote current measurement calibration currents and commands

Channel

Detector 2

Current range Test resistor*

50mA

100mA

400 Ω

200 Ω

Calibration currents*

-50mA

0mA

0mA

+50mA

-100mA

0mA

0mA

+100mA

Calibration commands*

:SENS3:CURR:RANG 50e-3

:SOUR1:FUNC:SHAP DC

:SENSE3:CURR:POL POS

:SOUR3:VOLT -20

:CAL:PROT:SENS3 <Current>

:SOUR3:VOLT 0

:CAL:PROT:SENS3 <Current>

:SENSE3:CURR:POL NEG

:CAL:PROT:SENS3 <Current>

:SOUR3:VOLT 20

:CAL:PROT:SENS3 <Current>

:SENS3:CURR:RANG 100e-3

:SOUR1:FUNC:SHAP DC

:SENSE3:CURR:POL POS

:SOUR3:VOLT -20

:CAL:PROT:SENS3 <Current>

:SOUR3:VOLT 0

:CAL:PROT:SENS3 <Current>

:SENSE3:CURR:POL NEG

:CAL:PROT:SENS3 <Current>

:SOUR3:VOLT 20

:CAL:PROT:SENS3 <Current>

:OUTP1 OFF

* Nominal values shown. Calculate actual current from characterized resistance and DMM voltage reading: I = V/R.

2-36 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

Step 7: Compliance calibration

Follow the steps below to calibrate compliance.

Table 2-14

summarizes calibration steps.

1. Connect the DMM to the Model 2520 testhead CURRENT OUTPUT jacks, as shown in

Figure 2-9

.

2. Select the DMM DC volts function, and enable auto-range.

3. Put the unit into the DC mode:

:SOUR1:FUNC:SHAP DC

4. Send this command to turn on the source output:

:OUTP1 ON

5. Send the following command to set the current to 100mA:

:SOUR1:CURR 0.1

6. Set the voltage compliance to 10.5V:

:SOUR1:VOLT:PROT 10.5

7. Note the DMM voltage reading, then send the value as the parameter for the following command:

:CAL:PROT:SOUR1:PROT <DMM_Reading>

For example, if the voltage is 10.45V, the correct command is:

:CAL:PROT:SOUR1:PROT 10.45

8. Set the voltage compliance to 3V:

:SOUR1:VOLT:PROT 3

9. Note the DMM voltage reading, then send the value as the parameter for the following command:

:CAL:PROT:SOUR1:PROT <Voltage>

10. Send this command to turn off the output:

:OUTP1 OFF

Table 2-14

Remote compliance calibration summary

Command

:SOUR1:FUNC:SHAP DC

:OUTP1 ON

:SOUR1:CURR 0.1

:SOUR1:VOLT:PROT 10.5

:CAL:PROT:SOUR1:PROT <DMM_Reading>

:SOUR1:VOLT:PROT 3

:CAL:PROT:SOUR1:PROT <DMM_Reading>

:OUTP1 OFF

Description

Select DC source mode.

Turn output on.

Source 100mA.

Set compliance to 10.5V.

Calibrate 10.5V compliance.

Set compliance to 3V.

Calibrate 3V compliance.

Turn output off.

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration 2-37

Step 8: Program calibration dates

Use the following commands to set the calibration date and calibration due date:

:CAL:PROT:DATE

:CAL:PROT:NDUE

<yyyy>, <mm>, <dd>

<yyyy>, <mm>, <dd>

(Calibration date)

(Next calibration due date)

Note that the year, month, and date must be separated by commas.

Step 9: Save calibration constants

Calibration is now complete. You can store the calibration constants in EEROM by sending the following command:

:CAL:PROT:SAVE

NOTE Calibration will be temporary unless you send the SAVE command.

Step 10: Lock out calibration

To lock out further calibration, send the following command after completing the calibration procedure:

:CAL:PROT:LOCK

2-38 Calibration Model 2520 Pulsed Laser Diode Test System Service Manual

3

Routine Maintenance

3-2 Routine Maintenance Model 2520 Pulsed Laser Diode Test System Service Manual

Introduction

The information in this section deals with routine type maintenance that can be performed by the operator and includes information on line fuse replacement.

Line fuse replacement

WARNING Disconnect the line cord at the rear panel, and remove all test leads connected to the instrument before replacing the line fuse.

The power line fuse is accessible from the rear panel and is integral with the AC power module (see

Figure 3-1 ).

Figure 3-1

Model 2520 rear panel

WARNING:

NO INTERNAL OPERATOR SERVICABLE PARTS, SERVICE BY QUALIFIED PERSONNEL ONLY.

MADE IN

U.S.A.

PULSE

SYNC

OUT

CAT I

!

DIGITAL I/O

IEEE-488

(CHANGE IEEE ADDRESS

WITH FRONT PANEL MENU)

TRIGGER LINK RS-232

TESTHEAD

CONN 1

!

!

LINE FUSE

SLOWBLOW

1.6A, 250V

LINE RATING

100-240VAC

50, 60Hz

140VA MAX.

TESTHEAD

CONN 2

CAUTION:

FOR CONTINUED PROTECTION AGAINST FIRE HAZARD, REPLACE FUSE WITH SAME TYPE AND RATING.

Line Fuse

Model 2520 Pulsed Laser Diode Test System Service Manual Routine Maintenance 3-3

Perform the following steps to replace the line fuse:

1. Using a small flat-blade screwdriver, carefully release the locking tab that secures the fuse carrier to the power module.

2. Pull out the fuse carrier, and replace the fuse with the type specified in Table 3-1 .

CAUTION To prevent instrument damage, use only the fuse rating and type spec-

ified in Table 3-1

.

3. Re-install the fuse carrier, pushing it in firmly until it locks into place.

NOTE If the power line fuse continues to blow, a circuit malfunction exists and must be

corrected. Refer to “Troubleshooting” on page 4-13 for additional information.

Table 3-1

Power line fuse

Line voltage

100-240V

Fuse rating

1.6A slow blow, 250V, 5 × 20mm

Keithley part no.

FU-106-1.6

3-4 Routine Maintenance Model 2520 Pulsed Laser Diode Test System Service Manual

4

Troubleshooting

4-2 Troubleshooting Model 2520 Pulsed Laser Diode Test System Service Manual

Introduction

This section of the manual will assist you in troubleshooting and repairing the Model 2520

Pulsed Laser Diode Test System. Included are self-tests, test procedures, troubleshooting tables, and circuit descriptions. Note that disassembly instructions are located in

Section 5

, and component layout drawings are at the end of

Section 6 .

Safety considerations

WARNING The information in this section is intended for qualified service personnel only. Do not perform these procedures unless you are qualified to do so. Some of these procedures may expose you to hazardous voltages that could cause personal injury or death. Use caution when working with hazardous voltages.

Repair considerations

Before making any repairs to the Model 2520, be sure to read the following considerations.

CAUTION The PC-boards are built using surface mount techniques and require specialized equipment and skills for repair. If you are not equipped and/or qualified, it is strongly recommended that you send the unit back to the factory for repairs or limit repairs to the PC-board replacement level. Without proper equipment and training, you could damage a PC-board beyond repair.

• Repairs will require various degrees of disassembly. However, it is recommended that the Front Panel Tests be performed prior to any disassembly. The disassembly

instructions for the Model 2520 are contained in Section 5 of this manual.

• Do not make repairs to surface mount PC-boards unless equipped and qualified to do so (see previous CAUTION).

• When working inside the unit and replacing parts, be sure to adhere to the handling

precautions and cleaning procedures explained in “Handling and cleaning” on page 5-2

.

• Many CMOS devices are installed in the Model 2520. These static-sensitive

devices require special handling as explained in “Static sensitive devices” on page 5-3

.

• Whenever a circuit board is removed or a component is replaced, the Model 2520 must be recalibrated. See

“Calibration” on page 2-1 for details on calibrating the

unit.

Model 2520 Pulsed Laser Diode Test System Service Manual Troubleshooting 4-3

Power-on self-test

During the power-on sequence, the Model 2520 will perform a checksum test on its

EPROM and test its RAM. If one of these tests fails, the instrument will lock up.

Front panel tests

There are three front panel tests: one to test the functionality of the front panel keys and

two to test the display. In the event of a test failure, refer to “Display board checks” on page 4-13

for details on troubleshooting the display board.

KEYS test

The KEYS test lets you check the functionality of each front panel key. Perform the following steps to run the KEYS test.

1. Display the MAIN MENU by pressing the MENU key.

2. Using the EDIT keys, select TEST, and press ENTER to display the SELF-TEST

MENU.

3. Select DISPLAY-TESTS, and press ENTER to display the following menu:

FRONT PANEL TESTS

KEYS DISPLAY-PATTERNS CHAR-SET

4. Select KEYS, and press ENTER to start the test. When a key is pressed, the label name for that key will be displayed to indicate that it is functioning properly. When the key is released, the message “No keys pressed” is displayed.

5. Pressing EXIT tests the EXIT key. However, the second consecutive press of EXIT aborts the test and returns the instrument to the SELF-TEST MENU. Continue pressing EXIT to back out of the menu structure.

DISPLAY PATTERNS test

The display test lets you verify that each pixel and annunciator in the vacuum fluorescent display is working properly. Perform the following steps to run the display test:

1. Display the MAIN MENU by pressing the MENU key.

2. Select TEST, and press ENTER to display the SELF-TEST MENU.

3. Select DISPLAY-TESTS, and press ENTER to display the following menu:

FRONT PANEL TESTS

KEYS DISPLAY-PATTERNS CHAR-SET

4-4 Troubleshooting Model 2520 Pulsed Laser Diode Test System Service Manual

4. Select DISPLAY-PATTERNS, and press ENTER to start the display test. There are five parts to the display test. Each time a front panel key (except EXIT) is pressed, the next part of the test sequence is selected. The five parts of the test sequence are as follows:

• Checkerboard pattern (alternate pixels on) and all annunciators.

• Checkerboard pattern and the annunciators that are on during normal operation.

• Horizontal lines (pixels) of the first digit are sequenced.

• Vertical lines (pixels) of the first digit are sequenced.

• Each digit (and adjacent annunciator) is sequenced. All the pixels of the selected digit are on.

5. When finished, abort the display test by pressing EXIT. The instrument returns to the FRONT PANEL TESTS MENU. Continue pressing EXIT to back out of the menu structure.

CHAR SET test

The character set test lets you display all characters. Perform the following steps to run the character set test:

1. Display the MAIN MENU by pressing the MENU key.

2. Select TEST, and press ENTER to display the SELF-TEST MENU.

3. Select DISPLAY-TESTS, and press ENTER to display the following menu:

FRONT PANEL TESTS

KEYS DISPLAY-PATTERNS CHAR-SET

4. Select CHAR-SET, and press ENTER to start the character set test. Press any key except EXIT to cycle through all displayable characters.

5. When finished, abort the character set test by pressing EXIT. The instrument returns to the FRONT PANEL TESTS MENU. Continue pressing EXIT to back out of the menu structure.

Principles of operation

The following information is provided to support the troubleshooting tests and procedures covered in this section of the manual. Refer to the following drawings:

Figure 4-1 — Overall block diagram

Figure 4-2 — Analog circuitry block diagram

Figure 4-3 — Power supply block diagram

Figure 4-4 — Digital circuitry block diagram

Model 2520 Pulsed Laser Diode Test System Service Manual Troubleshooting 4-5

Overall block diagram

Figure 4-1 shows an overall block diagram of the Model 2520. Circuitry may be divided

into two general areas:

• Analog circuits — includes measurement circuits for voltage, and I-V converter for current, A/D converters, and voltage bias and current source circuits.

• Digital circuits — includes the microcomputer that controls the analog section, front panel, and GPIB and RS-232 ports, the DSP (digital signal processor), and associated interfacing and data storage circuits.

4-6 Troubleshooting

Figure 4-1

Overall block diagram

Front Panel

Keypad

Model 2520 Pulsed Laser Diode Test System Service Manual

2 Line VFD

MC68332

Microprocessor

GPIB

RS-232

Digital I/O

Trigger Link

DSP

SRAM

Detector 1

D/A

10MHz

A/D

Detector 2

D/A

10MHz

A/D

Laser

D/A

10MHz

A/D

Voltage Source Detector 1

± 20V, 100mA Max

I/V Converter Detector 1

(4 Current Ranges)

Voltage Source Detector 2

± 20V,100mA Max

I/V Converter Detector 2

(4 Current Ranges)

Laser Diode Current Source

1A, 10V DC

5A, 9V Pulse

Voltage Measurement

(2 Voltage Ranges)

DETECTOR 1

DETECTOR 2

PULSED

OUT

PULSED

SENSE

Model 2520 Pulsed Laser Diode Test System Service Manual Troubleshooting 4-7

Analog circuits

Figure 4-2 shows a simplified block diagram of the analog circuits.

Measurement circuits

Voltage measurement circuits

The laser diode voltage measurement circuits consist of U12, U13, and associated circuitry. The two sections of U12 provide buffering for the HI and LO sense lines, while

U13 controls ranging with appropriate feedback elements.

Current measurement circuits

Signal conditioning for the detector input currents are provided by I-V converters, which convert the input signal currents to voltages that can be used by the A/D converters. U7,

U8, Q10, and Q11 form a compound op amp for detector #1 I-V conversion, while U10,

U17, Q15, and Q16 make up an identical op amp for detector #2 I-V conversion. Current ranging is provided by selecting various feedback resistors for the corresponding current ranges (10mA, 20mA, 50mA, and 100mA).

A/D converters

Each of the three measurement channels has its own 10MHz, 14-bit A/D converter. U31 provides A/D conversion for laser diode voltage measurements, while U43 and U53 perform A/D conversion for detector 1 and detector 2 current measurements, respectively.

A/D digital data is stored in high-speed FIFO (first-in, first-out) SRAM circuits (U27,

U29, U38-U42, and U49) for use by the DSP section (described below).

4-8 Troubleshooting Model 2520 Pulsed Laser Diode Test System Service Manual

Figure 4-2

Analog circuitry block diagram

Voltage

Clamp

U4, U6

U16,Q9

Laser Diode Current Source

Control Data

From MPU

High

DAC

U54

Low

DAC

U1

Pulse

High/Low

Switch

U5

Current

Amplifiers

U8, U18

Control Data

From MPU DAC

U1

Control Data

From MPU DAC

U2

Detector 1 Voltage Bias Source

Amplifier and

Current

Drive

U20

Detector 2 Voltage Bias Source

Amplifier and

Current

Drive

U3

Output

Stage

Q10-Q12

Sample Data to SRAM and DSP

A/D

Converter

U31

Laser Diode Voltage Measurement

Buffer and

Ranging

U12,U13

Sample Data to SRAM and DSP

A/D

Converter

Detector 1 Current Measurement

I-V

Converter and

Ranging

U43

U7,U8

Q10,Q11

Sample Data to SRAM and DSP

A/D

Converter

Detector 2 Current Measurement

I-V

Converter and

Ranging

U53

U10,U17

Q15,Q16

PULSED OUT

Terminals

DETECTOR 1

Bias Terminal

DETECTOR 2

Bias Terminal

PULSED SENSE

Terminals

DETECTOR 1

Current Input

Terminal

DETECTOR 2

Current Input

Terminal

Model 2520 Pulsed Laser Diode Test System Service Manual Troubleshooting 4-9

Source circuits

Voltage bias source circuits

Each Model 2520 voltage bias source is a digitally controlled source that can source up to

±20V @ 100mA. Digital control information from the MPU is converted by a DAC into an equivalent analog signal. U1 converts the detector 1 source data, while U2 converts detector 2 source data. Gain and 100mA drive capability for detector 1 and detector 2 sources, respectively, are provided by U20 and U3 to provide the full ±20V, 100mA output capability for each source.

Current pulse source circuits

The Model 2520 current source can output a maximum current of 1A DC @10V (10W) or

5A @ 9V (45W) current pulses.

DC and pulse high current source data from the MPU is converted into an analog signal by a 16-bit DAC made up of U54 and associated components. Pulse low data is converted by

DAC U1, and U5 performs pulse high/low switching. The signal from U5 is amplified by the current amplifiers, U8 and U18, and applied to the output stage (Q10 - Q12), which provides the current drive capability for the current source.

The voltage clamp circuit made up of U4, U6, U16, and Q9 maintains the output voltage at the programmed compliance value regardless of load, while the compliance detection circuit made up of U9 and U19 provides feedback to the MPU for an over-compliance condition. Over temperature detection for the current source is performed by RT1, R46, U15, and associated components.

4-10 Troubleshooting Model 2520 Pulsed Laser Diode Test System Service Manual

Power supply

Figure 4-3 shows a block diagram of the Model 2520 power supply system. The supply

has two separate power transformers, T1 and T2, as well as both regulated and unregulated supply voltages.

Unregulated circuits include the -8VF1 supply and -25VF1 supply that powers the output stage. Regulated circuits include ±5VFA, ±12VF, +12VD, and ±25VF supplies to power the various circuits throughout the instrument.

Figure 4-3

Power supply block diagram

Analog Circuits

± 5V ± 8V ± 12V ± 25V

Current

Source

Output

Stage

± 25V

Digital

Circuits

+5VD +12VD

Digital

Supply

Analog Supplies

Line In

100-240V AC

Line

Filter

Power

Transformers

Model 2520 Pulsed Laser Diode Test System Service Manual Troubleshooting 4-11

Digital circuitry

Refer to Figure 4-4

for the following discussion on digital circuitry.

Microcontroller

The core digital circuitry uses a Motorola 68332 microcontroller (U15) running at

16.78MHz. The memory configuration includes a flash EEPROM (U3 and U4) and a

RAM U2 and U17). Flash ROM support allows internal firmware upgrades using either the serial or GPIB port for downloading new firmware. All calibration constants and the saved setups are stored in a separate serial EEPROM (U13).

I/O circuits

External communication is provided via GPIB and serial interfaces. A 9914 GPIB

IEEE-488 standard interface IC is used for the GPIB (U5), and an IC (U20) provides the voltage conversion for the RS-232 port. U35 provides interfacing for the Digital I/O port, while U46 and Q6-Q11 provide Trigger Link I/O interfacing.

Digital signal processor

U47 is the DSP IC that processes raw voltage and current samples into final readings.

Voltage and current data for the DSP is read from the high-speed FIFO (first-in, first-out)

SRAM circuits (U27, U29, U38-U42, and U49) after being stored there by the A/D converters.

Display board circuits

The display board includes a microcontroller (U902) that controls the VFD (vacuum fluorescent display) and interprets key data. The microcontroller has four peripheral I/O ports that are used for the various control and read functions.

The VFD (vacuum fluorescent display) module (DS901) can display up to 49 characters.

Each character is organized as a 5 × 7 matrix of dots or pixels and includes a long underbar segment to act as a cursor. The display uses a common multiplexing scheme with each character refreshed in sequence. Circuitry includes the grid drivers and dot drivers.

4-12 Troubleshooting

Figure 4-4

Digital circuitry block diagram

Model 2520 Pulsed Laser Diode Test System Service Manual

ROM

U3, U4

RAM

U2, U17

Reset

Serial

Interface

U20

RS-232 Interface

U13

DSP

U47

Data From A/D

Converters SRAM

U27, U29

U38-U42,

U49

To Current and Voltage

Source Control DACs

Microprocessor

U15

GPIB

U5, U6

U19

IEEE-488 Interface

16.78MHz

Trigger

U46,

Q6-Q11

To Display

Board Controller

Trigger

Link

Digital I/O

U35

Digital

I/O

Model 2520 Pulsed Laser Diode Test System Service Manual Troubleshooting 4-13

Troubleshooting

Troubleshooting information for the various circuits is summarized below. Refer to the component layout drawings at the end of

Section 6 for component locations.

Display board checks

If the front panel display tests indicate that there is a problem on the display board, use

Table 4-1 . See

“Principles of operation” on page 4-4

for display circuit theory.

4

5

6

1

2

3

Table 4-1

Display board checks

Step

Item/ component

Front panel test

J1033

U902, pin 1

U902, pin 43

U902, pin32

U902, pin 33

Required condition Remarks

Verify that all segments operate.

+5V, ±5%

Goes low briefly on power up, and then goes high.

4MHz square wave.

Pulse train every 1 ms.

Brief pulse train when front panel key is pressed.

Use front panel display test.

Digital +5V supply.

Microcontroller RESET.

Controller 4MHz clock.

Control from main processor.

Key down data sent to main processor.

4-14 Troubleshooting Model 2520 Pulsed Laser Diode Test System Service Manual

Power supply checks

Power supply problems can be checked out using Table 4-2

. See “Principles of operation” on page 4-4 for circuit theory on the power supply.

Table 4-2

Power supply checks

Step

Item/ component* Required condition

7

8

5

6

3

4

1

2

9

10

11

12

Line fuse

Line power

TP1

TP2

TP14

TP15

TP16

TP20

TP21

TP22

TP23

TP32

Check continuity.

Plugged into live receptacle, power on.

+25V, ±10%

-25V, ±10%

+25V, ±5%

+12V, ±5%

+5V, ±5%

+5V, ±5%

-5V, ±5%

+12V, ±5%

-12V, ±5%

+3.3V, ±5%

* Test points (TP) are marked on circuit boards.

Remarks

Remove to check.

Check for correct power-up sequence.

Referenced to jumper W3.

Referenced to jumper W3.

Referenced to jumper W3.

Referenced to jumper W3.

Referenced to jumper W3.

Referenced to jumper W3.

Referenced to jumper W3.

Referenced to jumper W3.

Referenced to jumper W3.

Referenced to jumper W3.

Model 2520 Pulsed Laser Diode Test System Service Manual Troubleshooting 4-15

Digital circuitry checks

Digital circuit problems can be checked out using

Table 4-3 . See

“Principles of operation” on page 4-4 for a digital circuit description.

13

14

15

16

17

9

10

11

12

7

8

5

6

3

4

1

2

Table 4-3

Digital circuitry checks

Step

Item/ component

Power-on test

Clip W2

U15 pin 7

U15 pin 68

U15, A0-A18

U15, D0-D15

U15 pin 66

U20 pin 7

U20 pin 8

U5 pins 34-42

U5 pins 26-31

U5 pin 24

U5 pin 25

U15 pin 43

U15 pin 44

U15 pin 45

U15 pin 47

Required condition

RAM OK, ROM OK.

Digital common.

+5V

Low on power-up, then goes high.

Check for stuck bits.

Check for stuck bits.

16.78MHz.

Pulse train during RS-232 I/O.

Pulse train during RS-232 I/O.

Pulse train during IEEE-488 I/O.

Pulses during IEEE-488 I/O.

Low with remote enabled.

Low during interface clear.

Pulse train.

Pulse train.

Pulse train.

Pulse train.

Remarks

Verify that RAM and ROM are functional.

All signals referenced to digital common.

Digital logic supply.

MPU RESET line.

MPU address bus.

MPU data bus.

MPU clock.

RS-232 TX line.

RS-232 RX line.

IEEE-488 data bus.

IEEE-488 command lines.

IEEE-488 REN line.

IEEE-488 IFC line.

D_RETURN_DATA

D_SPI_DATA

D_SPI_CLK

D_SPI_STB

4-16 Troubleshooting Model 2520 Pulsed Laser Diode Test System Service Manual

Analog circuitry checks

Table 4-4 summarizes analog circuitry checks.

Table 4-4

Analog circuitry checks

Step Item/component

13

14

15

16

9

10

11

12

17

18

7

8

5

6

3

4

1

2

DETECTOR 1 jack

TP3

TP4

DETECTOR 2 jack

TP17

TP18

PULSED SENSE jacks

LASER V

L

TP5

TP6

Bias source 1

U20, pin 6

Bias source 2

U3, pin 6

LASER I

L

LASER I

L

TP40

TP7 range

source

source

* *Referenced to TP6, OUTPUT ON.

**Referenced to M20, OUTPUT ON.

Required condition

Apply +20mA

+2.5V*

-2.5V*

Apply +20mA

+2.5V*

-2.5V*

Apply +10V

Select 10V range

-2.5V*

+2.5V*

Set to +20V

+20V*

Set to +20V

+20V*

500mA range

500mA output

+10V**

+1.4V*

Remarks

Select detector 1 20mA range.

Detector 1 I-V converter high output.

Detector 1 I-V converter low output.

Select detector 2 20mA range.

Detector 2 I-V converter high output.

Detector 2 I-V converter low output.

Input 10V to V measure circuit.

V measure high output.

V measure low output.

Output +20V bias value.

Bias source #1 output.

Output +20V bias value.

Bias source #2 output.

Set to 500mA range, DC mode.

Output 500mA.

I source pulse high DAC output.

Current amplifier input.

Model 2520 Pulsed Laser Diode Test System Service Manual Troubleshooting 4-17

No comm link error

A “No Comm Link” error indicates that the front panel display processor has stopped communicating with the main processor, which is located on the motherboard. This error indicates that the main processor ROMs (U3 and U4) may require re-seating in their sockets. The ROMs may be reseated as follows:

1. Turn off the power, and disconnect the line cord and all other test leads and cables from the instrument.

2. Remove the case cover as outlined in “Case cover removal” on page 5-4

.

3. Locate the firmware ROMs, U3 and U4, located on the motherboard. These ROMs are the only IC installed in a socket. (Refer to the component layout drawing at the end of

Section 6

for exact location.)

4. Carefully push down on the ROM ICs to make sure it is properly seated in its socket.

CAUTION Be careful not to push down excessively. The motherboard could crack.

5. Connect the line cord, and turn on the power. If the problem persists, additional troubleshooting will be required.

4-18 Troubleshooting Model 2520 Pulsed Laser Diode Test System Service Manual

5

Disassembly

5-2 Disassembly Model 2520 Pulsed Laser Diode Test System Service Manual

Introduction

This section explains how to handle, clean, and disassemble the Model 2520 Pulsed Laser

Diode Test System. Disassembly drawings are located at the end of this section.

Handling and cleaning

To avoid contaminating PC board traces with body oil or other foreign matter, avoid touching the PC board traces while you are repairing the instrument. Certain board areas have high-impedance devices or sensitive circuitry where contamination could cause degraded performance.

Handling PC boards

Observe the following precautions when handling PC boards:

• Wear cotton gloves.

• Only handle PC boards by the edges and shields.

• Do not touch any board traces or components not associated with repair.

• Do not touch areas adjacent to electrical contacts.

• Use dry nitrogen gas to clean dust off PC boards.

Solder repairs

Observe the following precautions when you must solder a circuit board:

• Use an OA-based (organic activated) flux, and take care not to spread the flux to other areas of the circuit board.

• Remove the flux from the work area when you have finished the repair by using pure water with clean, foam-tipped swabs or a clean soft brush.

• Once you have removed the flux, swab only the repair area with methanol, then blow-dry the board with dry nitrogen gas.

• After cleaning, allow the board to dry in a 50°C, low-humidity environment for several hours.

Model 2520 Pulsed Laser Diode Test System Service Manual Disassembly 5-3

Static sensitive devices

CMOS devices operate at very high impedance levels. Therefore, any static that builds up on you or your clothing may be sufficient to destroy these devices if they are not handled properly. Use the following precautions to avoid damaging them:

CAUTION Many CMOS devices are installed in the Model 2520. Handle all semiconductor devices as being static sensitive.

• Transport and handle ICs only in containers specially designed to prevent static build-up. Typically, you will receive these parts in anti-static containers made of plastic or foam. Keep these devices in their original containers until ready for installation.

• Remove the devices from their protective containers only at a properly grounded work station. Also, ground yourself with a suitable wrist strap.

• Handle the devices only by the body; do not touch the pins.

• Ground any printed circuit board, into which a semiconductor device is to be inserted, to the bench or table.

• Use only anti-static type desoldering tools.

• Use only grounded-tip solder irons.

• Once the device is installed in the PC board, it is normally adequately protected, and you can handle the boards normally.

Assembly drawings

Use the assembly drawings located at the end of this section to assist you as you disassemble and re-assemble the Model 2520. Also, refer to these drawings for information about the Keithley part numbers of most mechanical parts in the unit.

5-4 Disassembly Model 2520 Pulsed Laser Diode Test System Service Manual

Case cover removal

Follow the steps below to remove the case cover to gain access to internal parts.

WARNING Before removing the case cover, disconnect the line cord and any test leads from the instrument.

1.

Remove handle — The handle serves as an adjustable tilt-bail. Adjust its position by gently pulling it away from the sides of the instrument case and swinging it up or down. To remove the handle, swing the handle below the bottom surface of the case and back until the orientation arrows on the handles line up with the orientation arrows on the mounting ears. With the arrows lined up, pull the ends of the handle away from the case.

2.

Remove mounting ears — Remove the screw that secures each mounting ear. Pull down and out on each mounting ear.

NOTE When re-installing the mounting ears, make sure to mount the right ear to the right side of the chassis, and the left ear to the left side of the chassis. Each ear is marked “RIGHT” or “LEFT” on its inside surface.

3.

Remove rear bezel — To remove the rear bezel, loosen the two screws that secure the rear bezel to the chassis, then pull the bezel away from the case.

4.

Remove bottom screws — Remove the six screws that secure the case to the chassis. They are located on the bottom of the case.

5.

Remove chassis — To remove the case, grasp the front bezel of the instrument, and carefully slide the chassis forward. Slide the chassis out of the metal case.

Motherboard removal

Perform the following steps to remove the motherboard. This procedure assumes that the case cover is already removed.

1. Remove the IEEE-488, DIGITAL I/O, RS-232, and TESTHEAD CONN 1 fasteners. The IEEE-488, DIGITAL I/O, RS-232, and TESTHEAD CONN 1 connectors each have two screws that secure the connectors to the rear panel. Remove these screws.

2. Remove the motherboard mounting screws. Remove the five mounting screws that secure the motherboard to the chassis.

Model 2520 Pulsed Laser Diode Test System Service Manual Disassembly 5-5

3. Unplug cables:

• Unplug the ribbon cables from J1007 and J1033.

• Unplug the cable going to the power supply module from J1011.

• Unplug the cable going to the OUTPUT indicator from J1034.

• Unplug the wires going to the rear panel PULSE SYNC OUT jack from

J1006.

4. Remove the motherboard. Slide the motherboard forward slightly until the rear panel connectors clear the holes in the rear panel, then remove the board.

During re-assembly, replace the motherboard, and start the IEEE-488,

DIGITAL I/O, RS-232, and TESTHEAD CONN1 connector screws and the board mounting screws. Tighten all the fasteners once they are all in place and the board is correctly aligned. Be sure to plug in all cables.

Front panel disassembly

Use the following procedure to remove the display board and/or the push-button switch pad.

1. Remove the front panel assembly. This assembly has four retaining clips that snap onto the chassis over four pem nut studs. Two retaining clips are located on each side of the front panel. Pull the retaining clips outward and, at the same time, pull the front panel assembly forward until it separates from the chassis.

2. Unplug the display board ribbon cables.

3. Using a thin-bladed screwdriver, pry the plastic PC board stop (located at the bottom of the display board) until the bar separates from the casing. Pull the display board from the front panel.

4. Remove the switch pad by pulling it from the front panel.

5-6 Disassembly Model 2520 Pulsed Laser Diode Test System Service Manual

Removing power components

The following procedures to remove the power supply and/or power module require that the case cover and motherboard be removed, as previously explained.

Power supply module removal

Perform the following steps to remove the power supply module:

1. Disconnect the wires that connect the power supply module on the bottom of the chassis to the rear panel power module.

2. Remove the screws that secure the power supply to the chassis bottom, then remove the module.

Power module removal

Perform the following steps to remove the rear panel power module:

1. Disconnect the power module's ground wire. This green and yellow wire connects to a threaded stud on the chassis with a kep nut.

2. Squeeze the latches on either side of the power module while pushing the module from the access hole.

Instrument re-assembly

Re-assemble the instrument by reversing the previous disassembly procedures. Make sure that all parts are properly seated and secured, and that all connections are properly made.

WARNING To ensure continued protection against electrical shock, verify that power line ground (green and yellow wire attached to the power module) is connected to the chassis. Also make sure the ground wires are attached to the power transformer mounting screws.

Also ensure the six bottom case screws are properly installed to secure and ground the case cover to the chassis.

Model 2520 Pulsed Laser Diode Test System Service Manual Disassembly 5-7

Testhead disassembly

Follow the procedures below in the following order to disassemble the testhead.

Case disassembly

1. Remove the eight screws that secure the case top to the case bottom.

2. Remove the nuts and washers that secure the four BNC PULSED and two triax

DETECTOR jacks to the front panel.

3. Slide the case top forward until it clears the BNC and triax jacks, then continue sliding the case top forward away from the case bottom.

Output board removal

1. Remove the two screws that secure the REMOTE INTERLOCK connector to the rear panel.

2. Remove the nut that secures the KEY INTERLOCK to the rear panel.

3. Unplug the ribbon cable from J4.

4. Remove the three screws that secure the output board to the standoffs.

5. Pull the output board forward until the KEY INTERLOCK and REMOTE INTER-

LOCK connector clear the rear panel, then remove the output board.

Input board removal

1. Remove the two screws that secure the MAINFRAME CONN 1 connector to the front panel.

2. Unplug the MAINFRAME CONN 2 ribbon cables from the input board.

3. Unplug the INTERLOCK STATUS and POWER ON indicator light cables from

J5 and J6.

4. Remove the screws and standoffs that secure the input board to the case bottom.

5. Pull the input board forward until the MAINFRAME CONN 1 connector clears the rear panel, then carefully remove the input board from the case bottom.

Testhead re-assembly

Re-assemble the testhead by reversing the above procedure. Be sure that all cables are connected, and that all screws, standoffs, and nuts are installed and properly secured.

5-8 Disassembly Model 2520 Pulsed Laser Diode Test System Service Manual

6

Replaceable Parts

6-2 Replaceable Parts Model 2520 Pulsed Laser Diode Test System Service Manual

Introduction

This section contains replacement parts information and component layout drawings for the Model 2520 Pulsed Laser Diode Test System.

Parts lists

The electrical parts lists for the Model 2520 are shown in tables at the end of this section.

For part numbers to the various mechanical parts and assemblies, use the Miscellaneous

parts list and the assembly drawings provided at the end of Section 5

.

Ordering information

To place an order, or to obtain information concerning replacement parts, contact your

Keithley representative or the factory (see inside front cover for addresses). When ordering parts, be sure to include the following information:

• Instrument model number (Model 2520)

• Instrument serial number

• Part description

• Component designation (if applicable)

• Keithley part number

Factory service

If the instrument is to be returned to Keithley Instruments for repair, perform the following:

• Call the Repair Department at 1-800-552-1115 for a Return Material Authorization

(RMA) number.

• Complete the service form at the back of this manual, and include it with the instrument.

• Carefully pack the instrument in the original packing carton.

• Write ATTENTION REPAIR DEPARTMENT and the RMA number on the shipping label.

Component layouts

The component layouts for the circuit boards are provided on the following pages.

Model 2520 Pulsed Laser Diode Test System Service Manual

Table 6-1

Mainframe digital board parts list

Circuit designation Description

C10 CAP, .33UF, 20%, 50V, CERAMIC

C105,C106,C146,C147,C186,C187 CAP, 22P, 5%, 100V, CERAMIC

C108

C111

CAP, 1UF, 20%, 35V, TANTALUM

CAP, .1UF, 20%,100V, CERAMIC

C116

C128-C132,C136,C137,C1,

C17,C22, C28,C30

C13,C15,C83-C85

C133-C135,C60,C63-C65,C67,

C72,C76, C82

C14

CAP, 10U, 20%, 16V, TANTALUM

CAP, 22U, 20%, 25V, ALUM ELEC

CAP, 220PF, 10%, 100V, CERAMIC

CAP, .1UF, 20%, 50V, CERAMIC

CAP, 2200P, 1%, 50V, CERAMIC

CAP, 22U, 20%, 25V, ALUM ELEC C140,C141,C169-C171,C178,C179,

C182,C183

C142-C145,C159,C166-C168,

C173-C177,C184

C148-C153

C158

C16,C46-C49,C101,C102,C104,

C138,C139

CAP, .1UF, 20%, 50V, CERAMIC

CAP, 1000P, 10%, 100V, CERAMIC

CAP, 100U, 20%, 16V, ALUM ELEC

CAP, 100PF, 5%, 100V, CERAMIC

CAP, 33PF, 5%, 100V, CERAMIC

CAP, 100PF, 5%, 100V, CERAMIC

CAP, .1UF, 20%, 50V, CERAMIC

C172

C180,C181

C185,C103,C107,C110,C112,C113,

C120-C127

C189

C190,C87,C93-C96,C100,C109,

C117-C119

C19-C21,C42-C45,C154,C160,

C163-C165,C188

C202-C205,C207,C210-C214

C206,C208,C309,C310.C311

C216,C217,C219,C220,C222,

C224-C226,C228

C218,C221,C223,C279,C281,

C283-C286

C227,C229,C230,C292-C294

C232-C236,C191,C192,C194,

C196,C199

CAP, .01uF, 20%, 50V, CERAMIC

CAP, 22U, 20%, 25V, ALUM ELEC

CAP, .01uF, 20%, 50V, CERAMIC

CAP, .1UF, 20%, 50V, CERAMIC

CAP, .01uF, 20%, 50V, CERAMIC

CAP, .1UF, 20%, 50V, CERAMIC

CAP, .01uF, 20%, 50V, CERAMIC

CAP, 100P, 10%, 100V, CERAMIC

CAP, .1UF, 20%, 50V, CERAMIC

Replaceable Parts 6-3

C-418-.01

C-609-22

C-418-.01

C-418-.1

C-418-.01

C-418-.1

C-418-.01

C-451-100P

C-418-.1

Keithley part no.

C-237-.33

C-465-22P

C-494-1

C-436-.1

C-546-10

C-609-22

C-451-220P

C-418-.1

C-532-2200P

C-609-22

C-418-.1

C-451-1000P

C-547-100

C-465-100P

C-465-33P

C-465-100P

C-418-.1

6-4 Replaceable Parts Model 2520 Pulsed Laser Diode Test System Service Manual

Table 6-1 (continued)

Mainframe digital board parts list

Circuit designation

C237

C239,C263,C287

C240-C245,C250,C253-C262,

C264-C278,C282

C246,C247,C249,C251,C252

C25,C41

C26,C114,C155,C157

C27

C280

C288-C291,C295-C300,C307,

C308,C238

C301-C306,C193,C195,C197,C198,

C200,C201

C31,C66,C68,C70,C74,C77-C81

C32,C37,C38,C40,C50-C54,C59,

C312-C320

C33,C35,C36,C57,C58,C61,C62,

C71,C75

C34

C39

C4,C9,C24

C55,C56

C6

C69,C73

C8,C115,C156,C161,C162

C86,C88-C92,C97-C99,C11,

C12,C18, C23,C29

CR1,CR2

CR13,CR14,CR17,CR18,

CR25-CR30

CR15,CR16

CR19-CR23

CR24

CR3,CR4,CR8-CR11

CR5,CR6

Description

CAP, 1000P, 10%, 100V, CERAMIC

CAP, 47P, 5%, 100V, CERAMIC

CAP, .1UF, 20%, 50V, CERAMIC

CAP, 220PF, 10%, 100V, CERAMIC

CAP, 15P, 1%, 100V, CERAMIC

CAP, 470U, 20%, 25V, ALUM ELEC

CAP, 100P, 10%, 100V, CERAMIC

CAP, 47PF, 10%, 100V, CERAMIC

CAP, .1UF, 20%, 50V, CERAMIC

CAP, .01uF, 20%, 50V, CERAMIC

CAP, 22U, 20%, 25V, ALUM ELEC

CAP, .1UF, 20%, 50V, CERAMIC

CAP, 47U, 20%, 50V, ALUM

DIODE, SWITCHING, MMBD914

DIODE, DUAL SWITCHING, BAV99L

Keithley part no.

C-451-1000P

C-465-47P

C-418-.1

C-451-220P

C-512-15P

C-478-470

C-451-100P

C-451-47P

C-418-.1

C-418-.01

C-609-22

C-418-.1

C-579-47

CAP, 470U, 20%, 50V, ALUM ELEC

CAP, 47PF, 10%, 100V, CERAMIC

C-570-470

C-451-47P

CAP, 22UF, 20%, 25V, TANTALUM C-440-22

CAP, 1000PF, 10%, 50V, MONO CERAMIC C-452-1000P

CAP, 470U, 20%, 25V, ALUM ELEC

CAPACITOR

CAP, .1UF, 10%, 25V, CERAMIC

CAP, .1UF, 20%, 50V, CERAMIC

C-557-470

C-606-470

C-495-.1

C-418-.1

RF-83

RF-82

DIODE, SCHOTTKY BARRIER, 50V, BAS86 RF-129

DIODE, DUAL COMMON ANODE,

BAW56LT2

RF-98

DIODE, MBR5130LT3

ULTRAFAST POWER RECTIFIER

ULTRAFAST POWER RECTIFIER

RF-115

RF-105

RF-107

Model 2520 Pulsed Laser Diode Test System Service Manual Replaceable Parts 6-5

Table 6-1 (continued)

Mainframe digital board parts list

Circuit designation Description Keithley part no.

CR7,CR12

F1

FOR CS-501

HS1,HS2,HS21-HS26

J1003

J1004

J1005

J1006,J1034

J1007

J1008

J1009

J1010

J1011

ULTRA FAST BRIDGE RECTIFIER,

EDF1BM

POLYSWITCH, SMD030-2

4-40X5/16 PHILLIPS PAN HD

HEAT SINK

CONN, MINI-D RIBBON, 26 PINS

CONN, CIRCULAR DIN

CONN, D-SUB DUAL STACK M-F

RF-123

FU-103

4-40X5/16PPH

HS-55

CS-1105-26

CS-762

CS-1072-1

LATCHING HEADER, FRICTON, SGL ROW CS-724-3

CONN, HEADER, 36 PINS CS-368-36

CONN, RIGHT ANGLE, 24 PIN

CONN, DUAL, 7-PIN-BERG

CONN, MALE, 4 PIN

CS-501

CONN, HEADER, STRAIGHT SOLDER PIN CS-368-10

CS-389-5

CS-288-4

J1012

J1033

CONN, BERG CS-339

CONN, HEADER, STRAIGHT SOLDER PIN CS-368-16

L1,L3,L16-L18,L20,L21 FERRITE BEAD

L2,L4-L15,L19,L22-L28,L30,L32 FERRITE CHIP, 600 OHM, BLM32A07

CH-91

CH-62

L29

L31

L33,L34,L36-L39,L42-L44,

L47-L52, L55-L57

INDUCTOR

INDUCTOR

FERRITE CHIP, 600 OHM, BLM32A07

CH-105-1

CH-89-1

CH-62

L35

Q1,Q2

Q3,Q5

Q4,Q6-Q11

R1,R2,R13,R14,R34-R37,R59-R61,

R68,R73

R111-R113

R117,R122,R146

R118,R119,R126-R129,R139

R120

R123

R125

R130,R132,R147

FERRITE BEAD

TRANS, N CHANNEL MOSFET, BUZ11

TRANS, NPN, MMBT3904

TRANS, N-MOSFET, VN0605T

RES, 10K, 1%, 100MW, THICK FILM

RES, 100, 1%, 100MW, THICK FILM

RES, 4.75K, 1%, 100MW, THICK FILM

RES, 100, 1%, 100MW, THICK FILM

RES, 15k, 1%, 100MW, THICK FILM

RES, 499, 1%, 100MW, THICK FILM

RES, 2.21K, 1%, 100MW, THICK FILM

RES, 475, 1%, 100MW, THICK FILM

CH-91

TG-211

TG-238

TG-243

R-418-10K

R-418-100

R-418-4.75K

R-418-100

R-418-15K

R-418-499

R-418-2.21K

R-418-475

6-6 Replaceable Parts Model 2520 Pulsed Laser Diode Test System Service Manual

Table 6-1 (continued)

Mainframe digital board parts list

Circuit designation Description

R131 RES, 24.3, 1%, 100MW, THICK FILM

R133,R136,R138,R163-R165,R175 RES, 1K, 1%, 100MW, THICK FILM

R134

R135,R137

RES, 30.1K, 1%, 100MW, THICK FILM

RES, 200, 1%, 100MW, THICK FILM

R140,R167,R169

R15,R16,R38-R40

R152,R154,R155

R158,R159,R160,R161

R162,R166

R168,R170,R200,R202-R206,R219,

R220,R233

RES, 100, 1%, 100MW, THICK FILM

THICK FILM SMT

RES, 475, 1%, 1/4W, METAL FILM

RES, 226, .1%, 1W, THICK FILM

RES, 10K, 1%, 100MW, THICK FILM

RES, 10K, 1%, 100MW, THICK FILM

R17,R18,R19,R20,R32 RES, 475, 1%, 1/4W, METAL FILM

R176-R179,R207-R210,R221-R224 RES, 909, 1%, .1W, THIN FILM

R180,R181,R211,R212,R225,R226 RES, 71.5, 1%, 100MW, THICK FILM

R182-R184,R213-R215,R227-R229 RES, 604, 1%, .1W, THIN FILM

R185,R218,R235

R189-R192,R195,R196

R216,R217,R230

R23,R26,R28

RES, 2K, 1%, 100MW, THICK FILM

RES, 5.11K, 1%, 100MW, THICK FILM

RES, 715, 1%, 100MW, THIN FILM

RES, 100, 1%, 1/4W, METAL FILM

R231,R193,R194,R197-R199,R201 RES, 49.9, 1%, 100MW, THICK FILM

R232,R236,R171-R174,R186-R188 RES, 100, 1%, 100MW, THICK FILM

R234,R121,R141-R145,R148-R151,

R153,R157

RES, 10K, 1%, 100MW, THICK FILM

R237-R242

R24,R25,R27,R33

RES, 49.9, 1%, 1/4W, METAL FILM

RES, 226, .1%, 1W, THICK FILM

R29,R49-R54,R56,R75-R80,R104 RES, 100, 1%, 100MW, THICK FILM

R3,R46,R48 RES, 2K, 1%, 100MW, THICK FILM

R30

R31

R4

R41,R43

R42,R44

R45,R47

R5

R57

RES, 332, 10%, 1/4W, METAL FILM

RES, 150, 1%, 100MW, THICK FILM

RES, 332K,1%, 100MW, THICK FILM

RES, 4.75K, 1%, 100MW, THICK FILM

RES, 249,1%, 100MW, THICK FILM

RES, 221, 1%, 100MW, THICK FILM

RES, 10M, 1%, 125MW, THICK FILM

RES, 33, 5%, 250mW, METAL FILM

Keithley part no.

R-418-24.3

R-418-1K

R-418-30.1K

R-418-200

R-418-100

TF-278-100

R-391-475

R-418-226

R-418-10K

R-418-10K

R-391-475

R-438-909

R-418-71.5

R-438-604

R-418-2K

R-418-5.11K

R-438-715

R-391-100

R-418-49.9

R-418-100

R-418-10K

R-391-49.9

R-418-226

R-418-100

R-418-2K

R-391-332

R-418-150

R-418-332K

R-418-4.75K

R-418-249

R-418-221

R-418-10M

R-376-33

Model 2520 Pulsed Laser Diode Test System Service Manual Replaceable Parts 6-7

U19

U2,U17

U20

U21,U23

U22,U24

U25

U26

U27,U39,U40

U28,U30

U29,U41,U42

U3

U31,U43,U53

U32,U44,U56

U33,U45,U57

U35

U36

U37

Table 6-1 (continued)

Mainframe digital board parts list

Circuit designation

R58

R62

R67,R87

R6-R11,R55,R63-R66,R69-R72,

R110

R74,R89-R92,R94-R103,R114

R81-R86,R105,R106,R115,R116

R88,R93,R107,R108,R109

SO37,SO3,SO4

T1

T2

TP13

U1

U13

U15

U16

Description

RES, 20, 1%, 100MW, THICK FILM

RES, 100, 5%, 250MW, METAL FILM

RES, .0499, 1%, 100MW, THICK FILM

RES, 1K, 1%, 100MW, THICK FILM

Keithley part no.

R-418-20

R-376-100

R-418-.0499

R-418-1K

RES, 10K, 1%, 100MW, THICK FILM

RES, 49.9, 1%, 100MW, THICK FILM

RES, 10, 10%, 100MW, THICK FILM

SOCKET, PLCC-032-T-A

TRANSFORMER

TRANSFORMER

SURFACE MOUNT PCB TEST POINT

IC, HIGH SPEED PWN CONTROLLER

R-418-10K

R-418-49.9

R-418-10

SO-143-32

TR-351A

TR-350A

CS-1026

IC-1120

IC, SERIAL EPROM 24LC16B

IC, MICROCONTROLLER MC68332-FC

IC, 2 INPUT EXCLUSIVE OR GATE,

NC7SZ86

LSI-153

LSI-161

IC-1180

IC, OCTAL INTER BUS TRANS, 75161

IC, 256K X 16 BIT CMOS RAM, 17NS

IC-647

LSI-249-1

IC, +5V RS-232 TRANSCEIVER, MAX202 IC-952

IC, VOLTAGE REGULATOR, LM317T IC-317

IC, VOLTAGE REGULATOR, LM337MP

IC, +5V VOLTAGE REGULATOR,

LM2940CT

IC-309

IC-576

IC, -5V LOW DROPOUT REGULATOR

LARGE SCALE IC SMT

IC-1370

LSI-239-1

IC, HEX SCHMITT INVERTER IC-1368

IC, 16 BIT BIDIRECTIONAL TRANSCEIV LSI-265

PROGRAMMED ROM

IC, 14 BIT MSPS A/D CONVERTOR

IC, CMOS ANAL SWITCH, DG444DY

IC, HIGH SPEED OP AMP DUAL

2520-800B01

LSI-264

IC-866

IC-1429

IC, PROTECTED QUAD POWER DRIVERS IC-1212

IC, STEP-DOWN VOLTAGE REGULATOR IC-1369

PROGRAMMED ROM 2520-801B01

6-8 Replaceable Parts Model 2520 Pulsed Laser Diode Test System Service Manual

Table 6-1 (continued)

Mainframe digital board parts list

Circuit designation

U38,U49

U4

U47

U48

U5

U50

U51,U52

U54

U55

U58

U59

U6

U60

U7,U9,U11,U12,U14

U8,U10,U18,U34,U46

VR1

W1-W4

Y1

Y2

Description Keithley part no.

32 BIT BUS SWITCH, HOTSWITCH

PROGRAMMED ROM

LARGE SCALE IC SMT

IC, QUAD 2 INPUT OR GATES

IC, GPIB ADAPTER, 9914A

IC, QUAD 2 INPUT NOR GATES

IC, HEX INVERTER

IC, 16 BIT MULTIPLYING DAC

LSI-260

2520-802B01

LSI-244

IC-1365

LSI-123

IC-1363

IC-1366

IC-1359

IC, DUAL FET OP AMP

IC, 8 STAGE SHIFT, C074HC409AM

IC, HEX INVERTER

IC, OCTAL INTERFACE BUS, 75160

IC-1128

IC-1026

IC-1367

IC-646

IC, HIGH PRECISION 10V REFERENCE

IC, HCPL0631, PACK

IC-1121

IC-1153

IC, POS NAND GATES/INVERT, 74HCT14 IC-656

DIODE, ZENER 30V, BZX84C30 DZ-106-30

JUMPER

CRYSTAL, FSM327

OSCILLATOR, 30M

J-24-1

CR-41

CR-56-4

Model 2520 Pulsed Laser Diode Test System Service Manual Replaceable Parts 6-9

Table 6-2

Mainframe display board parts list

Circuit designation

C901

C902,C904,C907,C908,C910

C903,C905,C906,C909,C911

C912

C913,C914

C915,C916

CR901,CR902,CR903,CR904

CR905,CR906

DS901

J1032

J1033

Q901,Q902

R901

R902

R903,R904

R905

R906

R907

R908

T901

U901,U904,U905

U902

U903

VR901

Y901

Description Keithley part no.

CAP, 22UF, 20%, 6.3, TANTALUM

CAP, .1UF, 20%,100V, CERAMIC

CAP, .1UF, 20%, 50V, CERAMIC

CAP, 2.2UF, 20%,100V, ALUM ELEC

CAP, 100UF, 20%, 16V, TANTALUM

CAP, 33PF, 10%, 100V, CERAMIC

DIODE, SWITCHING, 250MA, BAV103

DIODE, SWITCHING, MMBD914

C-417-22

C-436-.1

C-418-.1

C-503-2.2

C-504-100

C-451-33P

RF-89

RF-83

VACUUM FLUORESCENT DISPLAY

CONN, BERG

DD-51C

CS-339

CONN, HEADER, STRAIGHT SOLDER PIN CS-368-16

TRANS, NPN GEN PURPOSE, BC868 TG-293

RES NET, 15K, 2%, 1.875W

RES, 13K, 5%, 125MW, METAL FILM

RES, 4.7K, 5%, 250MW, METAL FILM

RES, 1M, 5%, 125MW, METAL FILM

TF-219-15K

R-375-13K

R-376-4.7K

R-375-1M

RES, 1K, 5%, 250MW, METAL FILM

RES, 240, 5%, 250MW, METAL FILM

RES, 10M, 5%, 125MW, METAL FILM

TRANSFORMER, TDK, ER14.5 SERIES

IC, LATCHED DRIVERS, UCN-5812EPF-1

PROGRAMMED ROM

IC, 32-BIT, SERIAL UCN5818EPF-1

DIODE, ZENER, 8.2V, MMBZ5237

CRYSTAL, 4MHZ

R-376-1K

R-376-240

R-375-10M

TR-300

IC-732

7001-800A02

IC-830

DZ-92

CR-36-4M

6-10 Replaceable Parts Model 2520 Pulsed Laser Diode Test System Service Manual

Table 6-3

Test head board parts list

Circuit designation

C1,C52,C53,C59,C60,C2

C11,C13,C17,C18,C29,C30,C33,

C34,C46-C49

C12,C22

C15,C32

C19

C20,C206-C209,C210,C211,

C215-C217,C27

C212

C23,C40

C231,C252

C24,C41

C25,C42

C254,C255

C257,C259

C26,C43

C28

C3,C36,C37,C4,C44,C45,C50,C51,

C56,C57

C5,C54,C55,C58,C6,C61-C63,

C69,C70

C64,C67,C68,C7,C71,C72,C8,C256,

C258

C65,C66

C9,C10

CR1,CR2,CR4,CR5

CR13,CR15,CR17,CR19,CR22

CR21,CR23,CR29,CR9,CR30,C31,

C14,C24

CR3,CR6-CR8,CR10-CR12,CR16,

CR18,CR20

CR32,CR33

HS22

HS3,HS20

J1,J10

J2,J3

Description

CAP, 470UF, 20%, 63V, ALUM ELEC

CAP, 22U, 20%, 25V, ALUM ELEC

CAP, 68PF, 10%, 100V, CERAMIC

CAP, 22PF, 10%, 100V, CERAMIC

CAP, .1UF, 20%, 50V, CERAMIC

CAP, .1UF, 20%, 50V, CERAMIC

CAP, .1UF, 10%, 25V, CERAMIC

CAP, 470P, 10%, 100V, CERAMIC

CAP, 1U, 10%, 50V, CERAMIC

CAP, 220PF, 10%, 100V, CERAMIC

CAP, 100P, 10%, 100V, CERAMIC

CAP, 33PF, 10%, 100V, CERAMIC

CAP, 1UF, 20%, 50V, CERAMIC

CAP, 47PF, 10%, 100V, CERAMIC

CAP, .1UF, 20%, 50V, CERAMIC

CAP, .1UF, 20%, 50V, CERAMIC

CAP, 22U, 20%, 25V, ALUM ELEC

CAP, .1UF, 20%, 50V, CERAMIC

CAPACITOR

CAP, 33U, 20%, 6.3V, TANTALUM

ULTRAFAST POWER RECTIFIER

DIODE, DUAL SWITCHING, BAV99L

DIODE, SWITCHING, MMBD914

DIODE, SWITCHING, MMBD914

SCHOTTKY DIODE

HEAT SINK

HEAT SINK

CONN, BNC

TRIAX RECEPTACLE, PCB MOUNT

C-609-22

C-418-.1

C-606-470

C-561-33

RF-105

RF-82

RF-83

RF-83

RF-125

HS-55

HS-43

CS-547

CS-995

Keithley part no.

C-477-470

C-609-22

C-451-68P

C-451-22P

C-418-.1

C-418-.1

C-495-.1

C-451-470P

C-564-1

C-451-220P

C-451-100P

C-451-33P

C-237-1

C-451-47P

C-418-.1

C-418-.1

Model 2520 Pulsed Laser Diode Test System Service Manual Replaceable Parts 6-11

Table 6-3 (continued)

Test head board parts list

Circuit designation

J4

J5

J6

J8,J9

K1,K2,K5-K10

K3,K4,K11,K12

L1,L2,L3,L4

L6-L8,L11-L15,L9,L16-L18

Q10,Q15

Q11,Q16

Q21

Q38,Q39,Q40,Q41

Q5,Q6

Q7-Q9,Q12-Q14,Q17-Q19,Q28,

Q36,Q37,Q20

R1,R103

R10,R12,R265,R266

R100

R102,R104

R11,R7

R14,R45

R15,R39,R46,R69

R16,R47

R18,R9

R2,R3,R92-R96,R101,R221,

R244-R247,R90

R222,R223

R238,R239

R24,R250,R260,R54

R248,R249

R252-R255,R258,R259,R36,

R37,R66,R67

R256,R257

R262,R263

R26-R35,R56-R65

Description Keithley part no.

CONN, .05 MINI-D RIBBION, 26 PINS

CONN, HEADER, 36 PINS

CS-1118-1

CS-368-36

CONN, HEADER, STRAIGHT SOLDER PIN CS-368-26

LATCHING HEADER, FRICTON, SGL ROW CS-724-3

NON LATCHING RELAY

RELAY

FERRITE BEAD

FERRITE CHIP, 600 OHM, BLM32A07

RL-242

RL-185

CH-91

CH-62

TRANS, NPN SILICON, 2N3904

TRANS, PNP SILICON, 2N3906

TRANS, N-MOSFET, VN0605T

IC, POWER VOLT REF, LT1004CZ 2.5

TRANS, P-CHAN, MOSFET, TP0610T

TRANS, N-MOSFET, VN0605T

TG-47

TG-84

TG-243

IC-929

TG-259

TG-243

RES, 121, 1%, 100MW, THICK FILM

RES, 15, 1%, .1W, THICK FILM

RES, 715, 1%, 100MW, THICK FILM

RES, 402, 1%, 100MW, THICK FILM

RES, 121K, 1%,100MW, THICK FILM

RES, 1, 1%, 100MW, THICK FILM

RES, .0499, 1%, 100MW, THICK FILM

RES, 49.9, 1%, 100MW, THICK FILM

RES, 200K, .1%, 1/10W, METAL FILM

RES, 1K, 1%, 100MW, THICK FILM

R-418-121

R-418-15

R-418-715

R-418-402

R-418-121K

R-418-1

R-418-.0499

R-418-49.9

R-263-200K

R-418-1K

RES, 10K, 1%, 100MW, THICK FILM

RES, 59K, 1%, 100MW, THICK FILM

RES, 200, 1%, 100MW, THICK FILM

RES, 499, 1%, 100MW, THICK FILM

RES, 24.3, 1%, 100MW, THICK FILM

RES, 24.3, 1%, 100MW, THICK FILM

RES, 1M, 1%, 100MW, THICK FILM

RES, 249, 1%, .1W, THIN FILM

R-418-10K

R-418-59K

R-418-200

R-418-499

R-418-24.3

R-418-24.3

R-418-1M

R-438-249

6-12 Replaceable Parts Model 2520 Pulsed Laser Diode Test System Service Manual

Table 6-3 (continued)

Test head board parts list

Circuit designation

R4,R6

R40,R41,R70,R71

R42,R43,R72,R73,R88,R89

R5,R8

R76-R79

R80-R83

R84,R85,R86,R87

R91,R224

R97,R98,R99

TP1,TP2,TP10,TP12,TP20-TP23

TP6,TP25-TP27

U1,U2

U10,U12,U13,U8

U11

U20,U3

U21

U22

U23

U4,U5,U6

U9

Description Keithley part no.

RES, 8.98K, .1%, .125W, THIN FILM

RES, 1.1K, .1%, .125W, THIN FILM

RES, 49.9, 1%, 1/4W, METAL FILM

RES, 10K, .1%, .125W, THIN FILM

RES, 402, 1%, 125W, THIN FILM

RES, 80.6, 1%, 125W, THIN FILM

RES, 121, .1%, .125W, THIN FILM

RES, 249, 1%, 100MW, THICK FILM

R-456-8.98K

R-456-1.1K

R-391-49.9

R-456-10K

R-456-402

R-456-80.6

R-456-121

R-418-249

RES, 100, 1%, 100MW, THICK FILM

SURFACE MOUNT PCB TEST POINT

CONN, TESTPOINT

IC, +5V, 12 BIT DAC

R-418-100

CS-1026

CS-985

IC-1329

IC, HIGH SPEED OP AMP DUAL IC-1429

IC, POS NAND GATES/INVERT, 74HCT14 IC-656

IC, HIGH VOLTAGE OP-AMP

IC, 3 TO 8 LINE DECODER

IC, +5V VOLTAGE REGULATOR,

LM2940CT

IC-1414

IC-1378

IC-576

IC, -5V, LOW DROPOUT REGULATOR

IC, 8 STAGE SHIFT, C074HC409AM

IC, HCPL0631, PACK

RES, 499, 1%, 1/4W, METAL FILM

TRANS, CURR REG, CDLL5313

IC-1370

IC-1026

IC-1153

R-391-499

TG-321

Model 2520 Pulsed Laser Diode Test System Service Manual Replaceable Parts 6-13

Table 6-4

Pulse board parts list

Circuit designation

C1

C10,C11,C12,C13

C14

C16,C19,C22,C24,C27,C29

C26,C28,C2,C31,C32,C39,C40,C44,

C45,C47

C3,C4,C6-C9,C15,C17,C18,

C20,C21,C23,C25

C33

C34

C35,C36

C37

C38

C41

C42

C46

C5

CR1

CR2,CR3,CR4,CR5,CR6,CR7

DS1,DS2

HS11,HS12

J1,J2

J3

J4

J5

K1,K2,K3

L1,L2

L3

Q1

Q10,Q11,Q12

Q13,Q14,Q16,Q19,Q24

Q18,Q21,Q22

Q2,Q3,Q4

Q25,Q26,Q27

Description

CAP, .1UF, 10%, 25V, CERAMIC

CAP, 680U, 20%, 50V, ALUM ELEC

CAP, 10U, 20%, 35V, TANTALUM

CAP, 22U, 20%, 25V, ALUM ELEC

CAP, .1UF, 20%, 50V, CERAMIC

CAP, .1UF, 20%, 50V, CERAMIC

Keithley part no.

C-495-.1

C-578-680

C-551-10

C-609-22

C-418-.1

C-418-.1

CAP, 2200P, 1%, 50V, CERAMIC

CAP, 150PF, 5%, 100V,CERAMIC

CAP, 270PF, 5%, 100V, CERAMIC

CAP, 33PF, 5%, 100V, CERAMIC

CAP, 47P, 5%, 100V, CERAMIC

CAP, 470U, 20%, 25V, ALUM ELEC

CAP, 2200P, 1%, 50V, CERAMIC

CAP, .1UF, 20%, 50V, CERAMIC

C-532-2200P

C-465-150P

C-465-270P

C-465-33P

C-465-47P

C-478-470

C-532-2200P

C-418-.1

CAP, 10PF, 5%, 50V, MONO CERAMIC

SCHOTTKY DIODE

DIODE, SWITCHING, MMBD914

LED, GRN LGT679-C0

C-452-10P

RF-121

RF-83

PL-107-1

HEAT SINK

CONN, BNC RIGHT ANGLE PLASTIC

HS-51

CS-506

CONN, D-SUB MALE, BOARDLOCK TYPE CS-848-9

CONN, HEADER, STRAIGHT SOLDER PIN CS-368-26

LATCHING HEADER, FRICTON, SGL ROW CS-724-3

FORM 2A2B POLARIZED RELAY, S28B-5V RL-207

FERRITE CHIP, 600 OHM, BLM32A07

FERRITE CHIP, 600 OHM, BLM32A07

CH-62

CH-62

TRANS, P-CHAN, MMBFJ175

HEXFET POWER MOSFET, N

TRANS, CURR REG, CDLL5313

TRANS, NPN, MMBT3904

TRANS, N-MOSFET, VN0605T

TRANS, PNP COMP SILICON AMP,

MPS8599

TG-311

TG-409

TG-321

TG-238

TG-243

TG-158

6-14 Replaceable Parts Model 2520 Pulsed Laser Diode Test System Service Manual

Table 6-4 (continued)

Pulse board parts list

Circuit designation

Q5,Q6,Q7,Q8,Q17,Q20,Q23

Q9

R1

R10

R11,R9,R51

R12,R20

R15

R16,R21,R14

R2

R22,R13

R24

R25

R26

R27

R28,R30

R29,R53-R59,R63

R3,R6,R7,R17-R19,R48,R67,R68

R33,R35

R34,R36,R32

R37,R40,R31

R38,R39,R41,R42

R4

R43,R49

R44

R45

R46

R47

R5,R23

R50

R52

R60

R64,R66

R65

R69,R70

R71

Description

TRANS, PNP, MMBT3906L

TRANS, HEXFET POWER MOSFET

RES, 2.5, .1%, 1.5W, METAL FOIL

RES, 22.1K, 1%, 100MW, THICK FILM

RES, 10K, 1%, 100MW, THICK FILM

RES, 475, 1%, 100MW, THICK FILM

RES, 24.9, 1%, 100MW, THICK FILM

RES, 324, 1%, 100MW, THIN FILM

RES, 215, 1%, 100MW, THICK FILM

RES, 38.3K, 1%, 100MW, THIN FILM

RES, 11.8K, 1%, 100MW, THIN FILM

RES, 43.2, 1%, 100MW, THICK FILM

RES, 2K, 1%, 100MW, THICK FILM

RES, 24.9, 1%, 100MW, THICK FILM

RES, 200, 1%, 100MW, THICK FILM

RES, 2.2, 5%, 1W, THICK FILM

RES, 1K, 1%, 100MW, THICK FILM

RES, 33, 5%, 250MW, METAL FILM

RES, 33, 5%, 250MW, METAL FILM

RES, 20, 1%, 100MW, THICK FILM

RESISTOR

RES, 100K, 1%, 100MW, THICK FILM

RES, 499, 1%, 100MW, THICK FILM

RES, 2M, 1%, 100MW, THICK FILM

RES, 39.2K, 1%, 100MW, THICK FILM

NTC THERMISTOR

RES, 1.74K, 1%, 100MW, THICK FILM

RES, 2.21K, 1%,100MW, THIN FILM

RES, 100, 1%, 100MW, THICK FILM

RES, 100, 1%, 100MW, THICK FILM

RES, 1K, 1%, 100MW, THICK FILM

RES, 49.9, 1%, 100MW, THICK FILM

RES, 10K, 1%, 100MW, THICK FILM

RES, 10M, 1%, 125MW, THICK FILM

RES, 3.32K, 1%, 100MW, THICK FILM

Keithley part no.

R-418-1K

R-376-33

R-376-33

R-418-20

R-509-2.2

R-418-100K

R-418-499

R-418-2M

R-418-39.2K

RT-24

R-418-1.74K

R-438-2.21K

R-418-100

R-418-100

R-418-1K

R-418-49.9

R-418-10K

R-418-10M

R-418-3.32K

TG-244

TG-304

R-501-2.5

R-418-22.1K

R-418-10K

R-418-475

R-418-24.9

R-438-324

R-418-215

R-438-38.3K

R-438-11.8K

R-418-43.2

R-418-2K

R-418-24.9

R-418-200

R-500-2.2

Model 2520 Pulsed Laser Diode Test System Service Manual

U13

U14,U25

U15,U19

U16,U3

U17

U18,U8

U21

U4,U20

U5

U7

U9

Table 6-4 (continued)

Pulse board parts list

Circuit designation

R72

R76

R77-R81

R8

R82,R83,R84

RT1

TP8,TP10

U1,U6

U10,U2

U11

U12

Replaceable Parts 6-15

Description

RES, 332, 1%, 100MW, THICK FILM

RES, 249, 1%, .1W, THIN FILM

RES, 100, 1%, 100MW, THIN FILM

RES, 8.87K, 1%, .1W, THIN FILM

RES, 2.21, 1%, 100MW, THICK FILM

THERMISTOR, PD=7MW/DEG C, 1500V,

613.74K

CONN, TESTPOINT

IC, 12-BIT VOLTAGE OUTPUT DAC

IC, 8 STAGE SHIFT, C074HC409AM

IC, POS VOLTAGE REG +15V, 500MA,

78M15

IC, +5V VOLTAGE REGULATOR,

LM2940CT

IC, HCPL0631, PACK

IC, -5V VOLTAGE REGULATOR

IC, VOLT. COMPARATOR, LM311M

IC, TINYLOGIC CMOS INVERTER

IC, +5V REFERENCE SOIC8

IC, 1000V OPAMP, LT1363CS8

IC, VOLTAGE REFERENCE SOIC8

IC, DUAL FET OPAMP

IC, SWITCHED INPUT OPAMP

IC, QUAD SPST CMOS SWITCH,

MAX4545CWP

IC, DUAL D-TYPE F/F, 74HC74

IC-1153

IC-184

IC-776

IC-1282

IC-1050

IC-1279

IC-1065

IC-1128

IC-1439

IC-1285

IC-773

Keithley part no.

R-418-332

R-438-249

R-438-100

R-438-8.87K

R-418-2.21

RT-8

CS-985

IC-1130

IC-1026

IC-194

IC-576

6-16 Replaceable Parts Model 2520 Pulsed Laser Diode Test System Service Manual

Table 6-5

Miscellaneous parts list

Qty

1

1

1

1

1

1

2

1

4

2

2

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

2

4

10

6

1

1

2

1

1

4

1

1

1

Description

AC ON/OFF LINE SWITCH

BEZEL, REAR

CABLE ASSEMBLY, BNC

CHASSIS

CHASSIS ASSEMBLY

CONDUCTIVE RUBBER SWITCH

CONN, FEMALE, 3 PIN, SHAPELESS

CONN, FEMALE, 4 PIN, SHAPELESS

CONNECTOR

CONNECTOR

CONNECTOR

CONNECTOR, FEMALE

CONNECTOR, HARDWARE KIT

CONNECTOR, HOUSING

CONNECTOR, HOUSING

COVER

COVER TOP

COVER, BOTTOM

DISPLAY ASSEMBLY

DISPLAY LENS

FOOT

FOOT, BLACK MOLDED POLY

FOOT, BLACK MOLDED POLY

FOOT, EXTRUDED

FOOT, RUBBER

FRONT PANEL, MODIFIED

FUSE

FUSE HOLDER

HANDLE

LED, BLUE

LED, HIGH POWER, BLUE

LED, RED/GREEN

LENS, LED

LINE CORD

MEMBRANE SWITCH, FRONT PANEL

MOUNTING EAR, LEFT

MOUNTING EAR, RIGHT

PCB SUPPORT

POWER SUPPLY

PRINTED FRONT PANEL

PRINTED FRONT PANEL

Keithley part no.

2520-324A

2520-326C

P-2400-110D

2520-311A

428-319A

FE-12

FE-10

FE-22A

FE-6

2520-305A

FU-106-1.6

FH-39

428-329F

PL-112-3

PL-118-1

PL-112-2

PM-6-1

428-303D

CA-290-1B

2520-301B

2520-302B

2520-315A

CS-287-3

CS-287-4

CS-236

CS-276

CS-236

CS-938

CS-713

CS-638-3

CS-638-3

2306-307A

6517-309B

CO-7

6430-313A

428-338B

428-328E

2520-329A

PS-41C

2520-306A

V-2520-306A

Model 2520 Pulsed Laser Diode Test System Service Manual

Table 6-5 (continued)

Miscellaneous parts list

Qty

1

1

1

1

2

Description

REAR PANEL

SAFETY COVER, MODIFIED

SWITCH

SWITCH

TRIAX CABLE

Replaceable Parts 6-17

Keithley part no.

2520-303A

2520-330A

SW-513A

SW-513A

CA-289-1A

6-18 Replaceable Parts Model 2520 Pulsed Laser Diode Test System Service Manual

A

Specifications

A-6 Specifications Model 2520 Pulsed Laser Diode Test System Service Manual

2520 Pulsed Laser Diode Test System

LASER DIODE PULSE OR DC CURRENT SOURCE SPECIFICATIONS

SOURCE

RANGE

0-500 mA

0 – 1.0 A DC

0 – 5.0 A Pulse

PROGRAMMING

RESOLUTION

10 μA

DRIVE CURRENT

APPROX.

ELECTRICAL

RESOLUTION

ACURACY

1,6

± (% rdg. + mA) 2,3

8 μA 0.2 + 0.45

0.2 + 4.5

RMS NOISE

(typical)

(1kHz-20MHz)

70 μA

RANGE

0-15 mA

800 0-150 mA

OFF CURRENT 4

PROGRAMMING

RESOLUTION

APPROX.

ELECTRICAL

RESOLUTION

1 μA 7 nA typ.

10 μA 70 nA typ.

ACURACY

1

± (% rdg. + mA)

0.2 + 0.45

0.2 + 4.5

TEMPERATURE COEFFICIENT (0°-18°C & 28°-50°C): r (0.15 x accuracy specification)/°C.

PULSE ON TIME 19 : 500ns to 5ms, 100ns programming resolution.

PULSE OFF TIME 19 : 20μs to 500ms, 10μs programming resolution.

PULSE DUTY CYCLE 19, 20, 21 : 0 to 99.6% for ” 1.0A;

VOLTAGE COMPLIANCE:

0 to 4% for > 1.0A.

3V to 10V, 10mV programming resolution

5

.

POLARITY: 1 quadrant source, polarity reversal available through internal relay inversion.

OUTPUT OFF: <200m : short across laser diode; measured at Remote Test

Head connector.

SETTING AND

RANGE

500mA

500mA

5.00A

5.00A

LOAD 7

10 : ¼ Watt

10 : ¼ Watt

1.5

: 1 Watt

1.5

: 1 Watt

PULSE

MODE

Fast

Slow

Fast

Slow

PULSE

OVERSHOOT

6 8 9

1.0%

0.1%

1.0%

0.1%

RISE/FALL

TIME 6,8,9,10

TYPICAL MAX.

55 ns

1 μs

100 ns

1 μs

80 ns

1.3 μs

130 ns

1.3 μs

LASER DIODE VOLTAGE MEASURE SPECIFICATIONS

RANGE

MINIMUM

RESOLUTION

ACURACY

± (% rdg. + volts) 1,12 (typical) 13

5.00 V

10.00 V

TEMPERATURE COEFFICIENT (0°-18°C & 28°-50°C):

MAX. LEAD RESOLUTION:

INPUT IMPEDANCE:

ACCURACY:

CURRENT:

RANGE

10.00 mA

20.00 mA

50.00 mA

100.00 mA

INPUT PROTECTION: The input is protected against shorting to the associated channel’s internal bias supply. The input is protected for shorts to external supplies up to 20V for up to 1 second with no damage,

SYSTEM SPEEDS

Reading Rates (ms)

15,16

Number of

2M

Source Points

17

:

±(1% + 50mV).

RMS NOISE (1kHz to 5MHz):

MINIMUM

0.7 μA

0.33 mV

0.66 mV

100

RESOLUTION

4

: for rated accuracy.

differential, 1M :

0.3% + 6.5 mV

0.3% + 8 mV

± (% rdg. + current)

To Memory r r

60 μV

120 μV

(0.15 x accuracy specification)/°C.

from each input to common. Input bias current ±7.5μA max.

PHOTODIODE VOLTAGE BIAS SOURCE SPECIFICATIONS

(each channel)

RANGE: 0 to ±20VDC.

PROGRAMMING RESOLUTION: 10mV.

160mA max. with V-Bias shorted to I-Measure.

1mV typical.

PHOTODIODE CURRENT MEASURE SPECIFICATIONS

(each channel)

1.4 μA

3.4 μA

6.8 μA

DC INPUT

IMPEDANCE

< 10

< 6

< 3

:

:

:

< 2.5 :

TEMPERATURE COEFFICIENT (0°-18°C & 28°-50°C): although calibration may be affected.

ACURACY

0.3% + 20 μA

0.3% + 65 μA

0.3% + 90 μA

0.3% + 175 μA

1,2

RMS NOISE (typical)

90 nA

180 nA

420 nA

840 nA

(0.15 x accuracy specification)/°C.

To GPIB

3

GENERAL SPECIFICATIONS

DCFLOATING VOLTAGE: User may float common ground up to

±10VDC from chassis ground.

COMMON MODE ISOLATION: >10 9 : .

OVERRANGE: 105% of range on all measurements and voltage compliance.

SOURCE OUTPUT MODES:

Fixed DC Level

Fixed Pulse Level

DC Sweep (linear, log and list)

Pulse Sweep (linear, log and list)

Continuous Pulse (continuous – low jitter)

PROGRAMMABILITY: -IEEE-488 (SCPI-1995.0), RS-232, 5 userdefinable power-up states plus factory default and *RST.

DIGITAL INTERFACE:

Safety Interlock : External mechanical contact connector and removable key switch.

Aux. Supply: +5V @ 300mA supply.

Digital I/O: 2 trigger input, 4 TTL/Relay Drive outputs (33V @

500mA max., diode clamped).

Tlink: 6 programmable trigger input/outputs.

Pulse Trigger Out BNC: +5V, 50 : output impedance, output trigger corresponding to current source pulse; pulse to trigger delay <100ns.

See Figure 3.

MAINS INPUT: 100V to 240V rms, 50-60Hz, 140VA.

WARRANTY: 1 year.

EMC: Conforms to European Union Directive 89/336/EEC (EN61326-1).

SAFETY: Conforms to European Union Directive 73/23/EEC (EN61010-

1) CAT 1.

VIBRATION: MIL-PRF-28800F Class 3, Random.

WARM-UP: 1 hour to rated accuracy.

DIMENSIONS, WEIGHT:

Main Chassis, bench configuration (with handle & feet): 105mm high × 238mm wide × 416mm deep (4 1/8 in. × 9 3/8 in. × 16 3/8 in.). 2.67kg (5.90 lbs).

Remote Test Head: 95mm high × 178mm deep (with interlock key installed) × 216mm wide (3 1/2 in. × 7 in. × 8 1/2 in.). 1.23kg (2.70 lbs).

ENVIRONMENT:

Operating: 0°-50°C, 70% R.H. up to 35°C. Derate 3% R.H./°C, 35°-

50°C.

Storage: -25° to 65°C.

10

1 5.3 6.8

[18] 9.5 18

100 [18] 48 120

1000 [18] 431 1170

HW

Rev. D

2/26/03

Model 2520 Pulsed Laser Diode Test System Service Manual Specifications A-7

2520 Pulsed Laser Diode Test System

1

Notes

1 year, 23°C ±5°C.

2

If Duty Cycle ·1 exceeds 0.2, accuracy specifications must be derated with an additional error term as follows:

500mA Range: ±0.1% rdg. · D ·1

5A Range: where:

±0.3% rdg. · D ·1

I = current setting

D = duty cycle

This derating must also be applied for a period equal to the time that D ·I was • 0.2.

4

3

Not including overshoot and setting time.

5

Output: 500mA DC on 500mA range and 1A DC on 5A range.

6

Refer to 2520 Service Manual for test setup of current accuracy.

7 Figures 1 and 2 are typical pulse outputs into resistive loads.

8 Typical

9 Per ANSI/IEEE Std 181-1977.

10 Per ANSI/IEEE Std 181-1977 10% to 90%.

11 DC accuracy ±700mV @ output terminal. 0.2

: typical output impedance.

12 At DC, 10μs measurement pulse width, Filter off.

13 Standard deviation of 10,000 readings with 10μs pulse width, filter off, with I source set to 0 amps DC.

14 The A/D converter has 14 bit resolution. The useful resolution is improved by reading averaging.

The useful resolution is:

Useful Resolution

Range

˜

2 14 Pulse Width (ns)

100ns

1

400ns

˜ Averaging Filter Setting

15 Excluding total programmed (Pulse ON time + Pulse OFF time).

16 Front panel off, calc off, filter off, duty cycle < 10%, binary communications.

17 Returning 1 voltage and 2 current measurements for each source point.

18 mode.

19

Valid for both continuous pulse and sweep modes.

20 Shown is the Power Distribution % based on current settings.

21

Timing Cycle ( pw

/

(pw + pd)

): 4% max.

Pulse Waveform Flatness - 500mA Into 20 Ohms

0.6

0.5

0.4

Current

(A)

0.3

0.2

0.1

0

0

Full Pulse

5

Expanded Pulse Top

10

Time ( s)

15 20

0.515

0.51

0.505

0.5

Current

(A)

0.495

0.49

25

0.485

Figure 1

Pulse Waveform Flatness - 5A into 2 ohms

Current

(A)

4

3

2

6

5

1

0

0

Full Pulse

5

Expanded Pulse Top

10 15

Time ( s)

20

4.96

25

4.94

5.06

5.04

5.02

5

Current

(A)

4.98

Figure 2

6

5

4

Volts

3

2

1

0

-1

-2

-1.00E-06

Pulse Output/Trigger Output Relationship

-5.00E-07

Trigger

Pulse

0.00E+00

Time

5.00E-07 1.00E-06 1.50E-06

Specifications are subject to change without notice.

Figure 3

HW

Rev. D

2/26/03

A-8 Specifications Model 2520 Pulsed Laser Diode Test System Service Manual

Accuracy calculations

The information below discusses how to calculate accuracy for both measurement and source specifications.

Measurement accuracy

Measurement accuracy specifications are stated as follows:

Accuracy = ±(% of reading + offset)

As an example of how to calculate the actual limits, assume an input current of 10mA on the 20mA range. You can compute the limits from one-year current measurement accuracy specifications as follows:

Accuracy = ±(% of reading + offset)

±[(0.3% × 10mA) + 65 μ A]

±(30 μ A + 65 μ A)

±95 μ A

Thus, the reading limits are: 10mA± 95 μ A, or from 9.905mA to 10.095mA.

Source accuracy

Source accuracy specifications are stated as follows:

Accuracy = ±(% of setting + offset)

For example, assume a DC source current of 200mA on the 500mA range. Limits are calculated from one-year current source accuracy specifications as follows:

Accuracy = ±(% of setting + offset)

±[(0.2% × 200mA) + 0.45mA]

±(0.4mA+ 0.45mA)

±0.85mA

Thus, the actual source current range is: 200mA± 0.85mA, or from 199.15mA to

200.85mA.

B

Calibration Reference

B-2 Calibration Reference Model 2520 Pulsed Laser Diode Test System Service Manual

Introduction

This appendix contains detailed information on the various Model 2520 remote calibration commands, calibration error messages, and methods to detect the end of each calibration step.

Section 2

of this manual covers detailed calibration procedures.

Command summary

Table B-1

summarizes Model 2520 calibration commands. These commands are covered in detail in the following paragraphs.

Table B-1

Calibration commands

Command

:CALibration

:PROTected

:CODE '<password>'

:CODE?

:SENSe[1] <NRf>

:DATA?

:SENSe2 <NRf>

:DATA?

:SENSe3 <NRf>

:DATA?

:SOURce[1] <NRf>

:DATA?

:PROTection

:DATA?

:LOW

:DATA?

:SOURce2 <NRf>

:DATA?

:SOURce3 <NRf>

:DATA?

:DATE <yyyy>,<mm>,<dd>

:DATE?

:NDUE <yyyy>,<mm>,<dd>

:NDUE?

:SAVE

:LOCK

:LOCK?

:COUNt?

Description

Calibration subsystem.

Calibration commands protected by password.

Unlock calibration. (Default password: KI002520.)

Query calibration code/password.

Calibrate active voltage measurement range.

Query voltage measurement calibration constants.

Calibrate active detector 1 current measurement range.

Query detector 1 current measurement calibration constants.

Calibrate active detector 2 current measurement range.

Query detector 2 current measurement calibration constants.

Calibrate active current source range.

Query current source calibration constants.

Calibrate voltage compliance DAC.

Query voltage compliance DAC calibration constants.

Calibrate low current output level DAC.

Query low current output level DAC calibration constants.

Calibrate detector 1 voltage bias source.

Query detector 1 voltage bias source calibration constants.

Calibrate detector 2 voltage bias source.

Query detector 2 voltage bias source calibration constants.

Program calibration year, month, day.

Query calibration date.

Program calibration due year, month, day.

Query calibration due date.

Save calibration data in EEPROM.

Lock out calibration.

Query if calibration is locked. (1 = locked; 0 = unlocked).

Query number of times Model 2520 has been calibrated.

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration Reference B-3

Miscellaneous commands

Miscellaneous commands are those commands that perform such functions as unlocking calibration, saving calibration constants, locking out calibration, and programming date parameters.

:CODE

(:CALibration:PROTected:CODE)

Purpose To unlock calibration enabling you to perform the calibration procedures.

Format

Parameter

Description

:cal:prot:code '<password>'

Up to an 8-character string including letters and numbers.

Note

The :CODE command sends the password/code and enables calibration when performing these procedures via remote. The correct password must be sent to the unit before sending any other calibration command.

The default remote password is KI002520.

• The :CODE command should be sent only once before performing calibration. Do not send :CODE before each calibration step.

• To change the code, first send the present code, then send the new code.

• The password parameter must be enclosed in single quotes.

• If you change the first two characters of the password to something other than "KI", you will not be able to unlock calibration from the front panel.

Example

:CAL:PROT:CODE 'KI002520'

Send default code of KI002520.

:COUNT?

(:CALibration:PROTected:COUNT?)

To request the number of times the Model 2520 has been calibrated.

Purpose

Format

Response

Description

:cal:prot:count?

Number of times calibrated.

The :COUNT? query may be used to determine the total number of times the Model 2520 has been calibrated.

Example

:CAL:PROT:COUNT?

Request calibration count.

B-4 Calibration Reference Model 2520 Pulsed Laser Diode Test System Service Manual

:LOCK

(:CALibration:PROTected:LOCK)

To lock out calibration.

Purpose

Format

Query

Response

:cal:prot:lock

:cal:prot:lock?

0

1

Calibration unlocked

Calibration locked

Description

Note

Example

The :LOCK command allows you to lock out calibration after completing the procedure. Thus, :LOCK performs the opposite of sending the password with the :CODE command. The :LOCK? query returns calibration lock status.

To unlock calibration, send the :CODE command with the appropriate password.

:CAL:PROT:LOCK

Lock out calibration.

:SAVE

(:CALibration:PROTected:SAVE)

To save calibration constants in EEROM after the calibration procedure.

Purpose

Format

Description

:cal:prot:save

The :SAVE command stores internally calculated calibration constants derived during comprehensive in EEROM. EEROM is non-volatile memory, and calibration constants will be retained indefinitely once saved. Generally, :SAVE is sent after all other calibration steps (except for :LOCK).

Note Calibration will be only temporary unless the :SAVE command is sent to permanently store calibration constants. Calibration data will not be saved if calibration was not unlocked by sending the :CODE command or if invalid calibration data exists.

Example

:CAL:PROT:SAVE

Save calibration constants.

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration Reference B-5

:DATE

(:CALibration:PROTected:DATE)

To program the calibration date.

Purpose

Format

Parameters

:cal:prot:date <yyyy>, <mm>, <dd>

<yyyy> = 2000 to 2099

<mm> = 1 to 12

<dd> = 1 to 31

Query

Response

Description

:cal:prot:date?

<year>, <month>, <day>

The :DATE command allows you to store the calibration date in instrument EEROM for future reference. You can read back the date from the instrument by using the :DATE? query, or by using the front panel CAL menu.

Note

Example

The year, month, and day parameters must be delimited by commas.

:CAL:PROT:DATE 2001,8,20

Send cal date (8/20/2001).

:NDUE

(:CALibration:PROTected:NDUE)

To send the next calibration due date to the instrument.

Purpose

Format

Parameters

:cal:prot:ndue <yyyy>, <mm>, <dd>

<yyyy> = 2000 to 2099

<mm> = 1 to 12

<dd> = 1 to 31

Query

Response

Description

:cal:prot:ndue?

<year>, <month>, <day>

The :NDUE command allows you to store the date, when calibration is next due, in instrument memory. You can read back the next due date by using the :NDUE? query, or by using the front panel CAL menu.

Note

Example

The next due date parameters must be delimited by commas.

:CAL:PROT:NDUE 2002,8,20

Send due date (8/20/2002).

B-6 Calibration Reference Model 2520 Pulsed Laser Diode Test System Service Manual

Measurement commands

:SENSe

(:CALibration:PROTected:SENSe[1])

(:CALibration:PROTected:SENSe2)

(:CALibration:PROTected:SENSe3)

Purpose

Format

To calibrate the active voltage or current measurement range.

:cal:prot:sens1 <Cal_voltage>

:cal:prot:sens2 <Cal_current>

:cal:prot:sens3 <Cal_current>

Parameters <Cal_current> = Within ±10% of positive full-range value

<Cal_voltage> = 0 ±0.1% of full-range value

Within ±10% of negative full-range value

Description

Example

The :CAL:PROT:SENS1 command calibrates the active voltage measurement range, while the CAL:PROT:SENS2 and :CAL:PROT:SENS3 commands calibrate the active detector 1 or detector 2 current measurement range respectively. During the calibration process, each command is sent three times for each range, once each with parameters of positive full range, 0, and negative full range. The appropriate calibration voltage or current must be applied to the appropriate input terminals.

:CAL:PROT:SENS2 20e-3

Calibrate detector 1 20mA range.

:DATA

(:CALibration:PROTected:SENSe[1]:DATA?)

(:CALibration:PROTected:SENSe2:DATA?)

(:CALibration:PROTected:SENSe3:DATA?)

Purpose

Query

To query measurement calibration constants.

:cal:prot:sens1:data?

:cal:prot:sens2:data?

:cal:prot:sens3:data?

Description The :CAL:PROT:SENS1:DATA? query requests voltage calibration constants, while the :CAL:PROT:SENS2:DATA? and

:CAL:PROT:SENS3:DATA? queries request calibration current constants for detector 1 and detector 2 respectively. Returned values are in

ASCII format separated by commas.

Example

:CAL:PROT:SENS1:DATA?

Query voltage constants.

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration Reference B-7

Current source commands

:SOURce[1]

(:CALibration:PROTected:SOURce[1])

To calibrate the current source.

Purpose

Format

Parameters

:cal:prot:sour1 <Resistance>

<Resistance> = 10 to 15 Ω (500mA range)

1.2 to 1.6

Ω (5A range)

Description The :CAL:PROT:SOUR1 command calibrates the current source. During the calibration process, this command is sent with the appropriate resistance connected to the testhead (see Section 2).

Example

:CAL:PROT:SOUR1 10

Calibrate 500mA range.

:DATA?

(:CALibration:PROTected:SOURce[1]:DATA?)

Purpose

Query

To query current source calibration constants.

:cal:prot:sour1:data?

Description The :CAL:PROT:SOUR1:DATA? query requests current source calibration constants. Returned constants are in ASCII format separated by commas.

Example

:CAL:PROT:SOUR1:DATA?

Query current source constants.

:PROTection

(:CALibration:PROTected:SOURce[1]:PROTection)

(:CALibration:PROTected:SOURce[1]:PROTection:DATA?)

Purpose

Format

Query

Description

To calibrate the voltage compliance DAC.

:cal:prot:sour1:prot

:cal:prot:sour1:prot:data?

The :CAL:PROT:SOUR1:PROT command calibrates the current source voltage compliance DAC. The :CAL:PROT:SOUR1:PROT:DATA? query requests voltage compliance DAC calibration constants. Returned constants are in ASCII format separated by commas.

Example

:CAL:PROT:SOUR1:PROT

Calibrate voltage compliance DAC.

B-8 Calibration Reference Model 2520 Pulsed Laser Diode Test System Service Manual

:LOW

(:CALibration:PROTected:SOURce[1]:LOW)

(:CALibration:PROTected:SOURce[1]:LOW:DATA?)

Purpose

Format

Query

Description

To calibrate the low output level DAC.

:cal:prot:sour1:low

:cal:prot:sour1:low:data?

The :CAL:PROT:SOUR1:LOW command calibrates the current source low output level DAC. The :CAL:PROT:SOUR1:LOW:DATA? query requests low output level DAC calibration constants. Returned constants are in ASCII format separated by commas.

Example

:CAL:PROT:SOUR1:LOW

Calibrate low output level DAC.

Voltage bias source commands

:SOURce

(:CALibration:PROTected:SOURce2)

(:CALibration:PROTected:SOURce3)

Purpose

Format

Parameters

To calibrate the detector 1 or detector 2 voltage bias source.

:cal:prot:sour2 <DMM_reading>

:cal:prot:sour3 <DMM_reading>

<DMM_reading> = +18 to +22V

-0.5 to +0.5

-18 to -22V

Description

Example

The :CAL:PROT:SOUR2 and :CAL:PROT:SOUR3 commands calibrate the detector 1 or detector 2 voltage bias source respectively. During the calibration process, this command is sent three times, once each with parameters of approximately +20V, 0V, and -20V. The voltage parameters are determined from a DMM reading.

:CAL:PROT:SOUR2 20

Calibrate detector 1 bias source.

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration Reference B-9

:DATA?

(:CALibration:PROTected:SOURce2:DATA?)

(:CALibration:PROTected:SOURce3:DATA?)

Purpose

Query

To query detector 1 or detector 2 voltage bias calibration constants.

:cal:prot:sour2:data?

:cal:prot:sour3:data?

Description

Example

The :CAL:PROT:SOUR2:DATA? and :CAL:PROT:SOUR3:DATA? queries request detector 1 and detector 2 calibration constants. Returned constants are in ASCII format separated by commas

:CAL:PROT:SOUR2:DATA?

Query detector 2 constants.

Detecting calibration errors

If an error occurs during any calibration step, the Model 2520 will generate an appropriate error message. Several methods to detect calibration errors are discussed below.

Reading the error queue

As with other Model 2520 errors, any calibration errors will be reported in the error queue.

(You can read the error queue by using the :SYST:ERR? query.)

Error summary

Table B-2

summarizes calibration errors.

Table B-2

Calibration errors

Error number

+500

+501

+502

+509

+510

+520

+521

+522

+523

+524

+525

Error message

"Date of calibration not set"

"Next date of calibration not set"

"Calibration data invalid"

"Not permitted with cal locked"

"Not permitted with cal un-locked"

"Source + gain data invalid"

"Source + offset data invalid"

"Source - gain data invalid"

"Source - offset data invalid"

"Source DAC Overflow"

"Source DAC Underflow"

B-10 Calibration Reference Model 2520 Pulsed Laser Diode Test System Service Manual

Status byte EAV (Error Available) bit

Whenever an error is available in the error queue, the EAV (Error Available) bit (bit 2) of the status byte will be set. Use the *STB? query to obtain the status byte, then test bit 2 to see if it is set. If the EAV bit is set, an error has occurred, and you can use the appropriate error query to read the error and at the same time clear the EAV bit in the status byte.

Generating an SRQ on error

To program the instrument to generate an IEEE-488 bus SRQ (Service Request) when an error occurs, send the following command: *SRE 4. This command will enable SRQ when the EAV bit is set. You can then read the status byte and error queue as outlined above to check for errors and to determine the exact nature of the error.

Detecting calibration step completion

When sending remote calibration commands, you must wait until the instrument completes the current operation before sending another command. You can use either *OPC? or *OPC to help determine when each calibration step is completed.

Using the *OPC? query

With the *OPC? (operation complete) query, the instrument will place an ASCII 1 in the output queue when it has completed each step. To determine when the OPC response is ready, do the following:

1. Repeatedly test the MAV (Message Available) bit (bit 4) in the status byte and wait until it is set. (You can request the status byte by using the *STB? query.)

2. When MAV is set, a message is available in the output queue, and you can read the output queue and test for an ASCII 1.

3. After reading the output queue, repeatedly test MAV again until it clears. At this point, the calibration step is completed.

Model 2520 Pulsed Laser Diode Test System Service Manual Calibration Reference B-11

Using the *OPC command

The *OPC (operation complete) command can also be used to detect the completion of each calibration step. In order to use *OPC to detect the end of each calibration step, do the following:

1. Enable operation complete by sending *ESE 1. This command sets the OPC (operation complete bit) in the standard event enable register, allowing operation complete status from the standard event status register to set the ESB (event summary bit) in the status byte when operation complete is detected.

2. Send the *OPC command immediately following each calibration command. For example:

:CAL:PROT:SOUR2 20;*OPC

Note that you must include the semicolon (;) to separate the two commands, and that the *OPC command must appear on the same line as the calibration command.

3. After sending a calibration command, repeatedly test the ESB (Event Summary) bit (bit 5) in the status byte until it is set. (Use *STB? to request the status byte.)

4. Once operation complete has been detected, clear OPC status using one of two methods: (1) use the *ESR? query, then read the response to clear the standard event status register, or (2) send the *CLS command to clear the status registers.

Note that sending *CLS will also clear the error queue and operation complete status.

Generating an SRQ on calibration complete

An IEEE-488 bus SRQ (service request) can be used to detect operation complete instead of repeatedly polling the Model 2520. To use this method, send both *ESE 1 and *SRE 32 to the instrument, then include the *OPC command at the end of each calibration command line, as covered above. Clear the SRQ by querying the ESR (using the *ESR? query) to clear OPC status, then request the status byte with the *STB? query.

Refer to your controller's documentation for information on detecting and servicing SRQs.

B-12 Calibration Reference Model 2520 Pulsed Laser Diode Test System Service Manual

Index

Numerics

Current source commands

SOURce

B-7

A

Aborting calibration steps

2-9

Assembly drawings

5-3

C

Calibration

2-1, 2-6

Calibration commands

B-2

Calibration considerations 2-4

Calibration cycle 2-5

Recommended calibration equipment

2-5

Resistor characterization

2-5

Calibration errors

2-9, B-9

Front panel error reporting 2-9

Remote error reporting

2-9

Calibration menus 2-6

Calibration Reference

B-1

Case cover removal 5-4

Changing the password

2-8 by remote 2-8 from the front panel 2-8

Command summary

B-2

Component layouts

6-2

Current measurement accuracy 1-13

Current source accuracy

1-9

Current source commands

B-7

DATA?

B-7

LOW B-8

PROTection

B-7

D

Detecting calibration errors

B-9

Error summary

B-9

Generating an SRQ on error B-10

Reading the error queue

B-9

Status byte EAV (Error Available) bit

B-10

Detecting calibration step completion B-10

Generating an SRQ on calibration complete

B-11

Using the *OPC command

B-11

Using the *OPC? query B-10

Disassembly 5-1

E

Environmental conditions

2-4

Line power 2-4

Temperature and relative humidity 2-4

Warm-up period 2-4

F

I

Factory service 6-2

Front panel calibration

2-10

Front panel disassembly 5-5

Front panel tests

4-3

CHAR SET test

4-4

DISPLAY PATTERNS test 4-3

KEYS test 4-3

H

Handling and cleaning 5-2

Handling PC boards

5-2

Solder repairs 5-2

Instrument re-assembly 5-6

L

Line fuse replacement 3-2

M

Measurement commands

B-6

DATA

B-6

SENSe B-6

Miscellaneous commands

B-3

CODE B-3

COUNT?

B-3

DATE B-5

LOCK B-4

NDUE

B-5

SAVE

B-4

Model 2520 rear panel 3-2

Motherboard removal 5-4

N

No comm link error 4-17

O

Ordering information 6-2

P

R

Recommended test equipment 1-5

Resistor characterization

1-5

Remote calibration

2-22

command summary

2-22

procedure

2-23

Removing power components

5-6

Power module removal

5-6

Power supply module removal

5-6

Repair considerations 4-2

Resetting the calibration password

2-8

Restoring factory defaults

1-6

Routine Maintenance

3-1

S

Parts lists 6-2

Mainframe digital board 6-3

Mainframe display board 6-9

Miscellaneous 6-16

Pulse board 6-13

Test head board

6-10

Performance Verification 1-1

Performing the verification test procedures

1-6

Test considerations 1-7

Test summary 1-6

Power line fuse

3-3

Power-on self-test

4-3

Principles of operation 4-4

Analog circuits

4-7

A/D converters

4-7

Measurement circuits

4-7

Source circuits

4-9

Digital circuitry

4-11

Digital signal processor

4-11

Display board circuits

4-11

I/O circuits 4-11

Microcontroller

4-11

Overall block diagram

4-5

Power supply

4-10

Safety considerations

4-2

Specifications

A-5

Static sensitive devices 5-3

T

Testhead connections

1-7, 2-10

Testhead disassembly 5-7

Case disassembly 5-7

Input board removal 5-7

Output board removal 5-7

Testhead re-assembly

5-7

Troubleshooting

4-1, 4-13

Analog circuitry checks 4-16

Digital circuitry checks 4-15

Display board checks

4-13

Power supply checks

4-14

U

Unlocking calibration 2-7

by remote

2-7

from the front panel

2-7

V

Verification limits

1-6

Example limits calculation 1-6

Verification test requirements

1-4

Environmental conditions

1-4

Line power 1-4

Warm-up period 1-4

Viewing calibration dates and calibration count

2-9

Voltage bias source accuracy

1-15

Voltage bias source commands

B-8

DATA?

B-9

SOURce B-8

Voltage measurement accuracy

1-8

Service Form

Name and Telephone No. _________________________________________________

Company ______________________________________________________________

List all control settings, describe problem and check boxes that apply to problem. _________________________

__________________________________________________________________________________________

__________________________________________________________________________________________

❑ Intermittent ❑ Analog output follows display ❑ Particular range or function bad; specify

_______________________________

❑ IEEE failure ❑ Obvious problem on power-up

❑ Front panel operational ❑ All ranges or functions are bad

❑ Batteries and fuses are OK

❑ Checked all cables

Display or output (check one)

❑ Drifts

❑ Overload

❑ Unable to zero

❑ Will not read applied input

❑ Calibration only ❑ Certificate of calibration required

(attach any additional sheets as necessary)

❑

❑

Unstable

Data required

Show a block diagram of your measurement including all instruments connected (whether power is turned on or not). Also, describe signal source.

Where is the measurement being performed? (factory, controlled laboratory, out-of-doors, etc.) ______________

__________________________________________________________________________________________

What power line voltage is used?___________________ Ambient temperature? ________________________ °F

Relative humidity? ___________________________________________Other? ___________________________

Any additional information. (If special modifications have been made by the user, please describe.)

__________________________________________________________________________________________

__________________________________________________________________________________________

Be sure to include your name and phone number on this service form.

Specifications are subject to change without notice.

All Keithley trademarks and trade names are the property of Keithley Instruments, Inc.

All other trademarks and trade names are the property of their respective companies.

Specifications are subject to change without notice.

All Keithley trademarks and trade names are the property of Keithley Instruments, Inc.

All other trademarks and trade names are the property of their respective companies.

A G R E A T E R M E A S U R E O F C O N F I D E N C E

Keithley Instruments, Inc.

Corporate Headquarters • 28775 Aurora Road • Cleveland, Ohio 44139 • 440-248-0400 • Fax: 440-248-6168 • 1-888-KEITHLEY (534-8453) • www.keithley.com

12/04

A G R E A T E R M E A S U R E O F C O N F I D E N C E

Keithley Instruments, Inc.

Corporate Headquarters • 28775 Aurora Road • Cleveland, Ohio 44139 • 440-248-0400 • Fax: 440-248-6168 • 1-888-KEITHLEY (534-8453) • www.keithley.com

12/04