Keithley 2002 Repair Manual
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Keithley 2002 Repair Manual

Keithley 2002 Repair Manual

Multimeter
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Model 2002
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Contains Servicing Information

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  • Page 1 Model 2002 Multimeter Repair Manual Contains Servicing Information...
  • Page 2 Keithley Instruments, Inc. • 28775 Aurora Road • Cleveland, OH 44139 • 440-248-0400 • Fax: 440-248-6168 • http://www.keithley.com CHINA: Keithley Instruments China • Yuan Chen Xin Building, Room 705 • 12 Yumin Road, Dewai, Madian • Beijing 100029 • 8610-62022886 • Fax: 8610-62022892 FRANCE: Keithley Instruments SARL •...
  • Page 3 Model 2002 Multimeter Repair Manual ©1995, Keithley Instruments, Inc. Test Instrumentation Group All rights reserved. Cleveland, Ohio, U.S.A. Second Printing June 1998 Document Number: 2002-902-01 Rev. B...
  • Page 4 Addendum A (Document Number 2002-902-02) ................October 1995 Revision B (Document Number 2002-902-01)..................June 1998 All Keithley product names are trademarks or registered trademarks of Keithley Instruments, Inc. Other brand and product names are trademarks or registered trademarks of their respective holders.
  • Page 5 (IEC) Standard IEC 664, digital multimeter measuring circuits The types of product users are: (e.g., Keithley Models 175A, 199, 2000, 2001, 2002, and 2010) measuring circuits are Installation Category II. All other instru- Responsible body is the individual or group responsible for the use ments’...
  • Page 6 fire hazard. leads, and input jacks, must be purchased from Keithley Instru- ments. Standard fuses, with applicable national safety approvals, Chassis connections must only be used as shield connections for may be used if the rating and type are the same.

  • Page 7: Table Of Contents

    Table of Contents Routine Maintenance Introduction ................................1-1 Line fuse replacement ............................1-1 Current fuse replacement ............................. 1-2 1.3.1 Front AMPS input fuse ..........................1-2 1.3.2 Rear AMPS input fuse ..........................1-3 Fan filter cleaning ..............................1-3 Firmware updates ..............................1-3 Troubleshooting Introduction .................................
  • Page 8 2.11.9 A/D converter ground multiplexer tests ....................2-52 2.11.10 Input buffer tests ............................2-55 2.11.11 Open-circuit ohms tests ........................... 2-56 2.11.12 20V range multiplexer tests ........................2-58 2.11.13 Ohms tests..............................2-61 2.11.14 100:1 input divider test ..........................2-63 2.11.15 Overload tests ............................2-64 2.11.16 Calibration/frequency compensation DAC tests ..................
  • Page 9 Front AMPS input fuse location ........................1-2 Figure 1-3 Rear AMPS input fuse location ........................1-3 Troubleshooting Figure 2-1 Model 2002 overall block diagram ......................2-7 Figure 2-2 Power supply block diagram........................2-8 Figure 2-3 Display board block diagram ........................2-8 Figure 2-4 Digital board block diagram ........................
  • Page 10 List of Tables Routine Maintenance Table 1-1 Power line fuse............................. 1-1 Table 1-2 Power line fuse............................. 1-2 Troubleshooting Table 2-1 Diagnostic bit pattern ........................... 2-3 Table 2-2 R1_STB register control bits........................2-4 Table 2-3 R2_STB register control bits........................2-5 Table 2-4 MUX_STB register control bits ........................

  • Page 11: Routine Maintenance

    filter element for the cooling fan. NOTE Firmware updates: Recommends a course of action for firmware updates provided by Keithley. If the power line fuse continues to blow, a circuit malfunction exists and must be cor- rected. Refer to the troubleshooting sec-...

  • Page 12: Current Fuse Replacement

    1100V PEAK PEAK Table 1-2 2001 MULTIMETER Power line fuse 500V PEAK INPUTS RANGE Size Rating Keithley Part No. AUTO FRONT/REAR 2A 250V AMPS RANGE 5 × 20mm 250V, 2A, Slo-Blo FU-48 WARNING AMPS Disconnect the instrument from the Fuse...

  • Page 13: Rear Amps Input Fuse

    FOR CONTINUED PROTECTION AGAINST FIRE HAZARD,REPLA FOR CONTINUED PROTECTION AGAINST FIRE HAZARD,REPLA It is possible that you may receive a firmware update from Keithley to enhance operation and/or fix “bugs”. The firm- ware for the main microprocessor is contained in two Amps...

  • Page 14: Troubleshooting

    Troubleshooting WARNING Diagnostics: Explains how to use the Diagnostics test mode of the Model 2002. In general, Diagnostics The information in this section is in- locks-up the instrument in various states of operation. tended for qualified service personnel. With the instrument in a static state, you can then...

  • Page 15: Repair Considerations

    Troubleshooting Repair considerations Front panel tests Before making any repairs to the Model 2002, be sure to read There are two Front Panel Tests; one to test the functionality the following considerations. of the front panel keys and one to test the display. In the event of a test failure, refer to paragraph 2.7 for details on trouble-...

  • Page 16: Character Set Test

    The four control registers are made up of the following ICs: Diagnostics AD_STB: U811, U810, U809 MUX_STB: U206, U207 The Model 2002 has diagnostic test modes that allow you to R1_STB: U203, U222, U224 “freeze” instrument operation letting you check logic levels R2_STB: U400, U406, U411, U432 on the various control registers.

  • Page 17: Table 2-2 R1_Stb Register Control Bits

    Troubleshooting Table 2-2 R1_STB register control bits Register IC* Range and function U224 U203 U221 200mV-20V DC 10011111 01110000 11101001 200V, 1000V DC 10011111 00000110 11101001 200 µ A DC 00010111 00000110 11101001 2mA DC 00001111 00000110 11101001 20mA DC 00111111 00000110 11101001...

  • Page 18: Display Board Checks

    Register IC* there is a problem on the display board, use Table 2-5. Cir- cuit theory for the display is provided in paragraph 2.9.1. Range and function U206 U207 Drawing reference: Display Board; 2002-110 200mV DC 11000000 00001111 2V DC 10100000...

  • Page 19: Principles Of Operation

    2002, while Figures 2-2 through 2-5 show block diagrams of bleshooting tests and procedures previously covered in this the power supply, display board, digital board, and analog section of the manual. Most circuits in the Model 2002 are board respectively. tested and/or exercised by Built-in Test, which is described in detail in paragraphs 2.10 and 2.11.

  • Page 20: Figure 2-1 Model 2002 Overall Block Diagram

    Troubleshooting Figure 2-1 Model 2002 overall block diagram...

  • Page 21: Figure 2-2 Power Supply Block Diagram

    Troubleshooting +15V ±15V Supply CR113 C112, C113 U107, U109 -15V Fuse: F101 Power Transformer Power 110/120VAC T100 Switch: S101 +BS (34V to 38V) Bootstrap Supply CR114 - CR117 Common 3 110/120V Switching C116, C117 Q101, Q102, Q103, Q106 -BS (-34V to -38V) U102, U105 K101, K102 +5V Supply...

  • Page 22: Figure 2-4 Digital Board Block Diagram

    Troubleshooting U637, U638 U635, U636, U608 NVRAM GPIB Microprocessor U632 - U634 U621 - U623 U631 IEEE - 488 Interface Control/Data A/D Interface U614 Trigger/Digital I/O Figure 2-4 Digital board block diagram...

  • Page 23: Figure 2-5 Analog Board Block Diagram

    Troubleshooting Figure 2-5 Analog board block diagram 2-10...

  • Page 24: Display Board Circuit Theory

    Troubleshooting 2.9.2 Display board circuit theory Pre-regulator circuit The pre-regulator circuit regulates power to the transformer. The following information provides some basic circuit theo- When power is applied to the instrument, a power transform- ry that can be used as an aid to troubleshoot the display and er secondary voltage (pins 12 and 13) is rectified (CR622), keyboard.

  • Page 25: Built-In Test Overview

    Troubleshooting 2.10 Built-in test overview will be applied to the +RELAY1 line, which energizes relay K101 to select the 110V setting. Conversely, when the volt- BUILT-IN TEST is used to test and exercise various circuits age at the inverting input is less than 4V, the output of U102 goes high and turns off Q106.
  • Page 26 Troubleshooting Table 2-7(cont.) Table 2-7(cont.) Built-in test summary Built-in test summary Test Circuit tested/exercised Test Circuit tested/exercised 202 Series Integration: 303 Series Input Buffer: 202.1 Baseline (for test 202.2) 303.1 Input Buffer 202.2 Integration Period Bit I15 202.3 Baseline (for test 202.4) 304 Series Open-circuit Ohms: 202.4...
  • Page 27 Troubleshooting Table 2-7(cont.) Table 2-7(cont.) Built-in test summary Built-in test summary Test Circuit tested/exercised Test Circuit tested/exercised 405 Series Absolute Value (X10 Gain): 410 Series True RMS Converter: 405.1 Gain Comparison (Large +DAC Out- 410.1 True RMS Converter put) 405.2 Gain Comparison (Non-inverting) 411 Series Filters:...

  • Page 28: Using Built-In Test

    Troubleshooting 2.10.1 Using Built-In Test 6. If the non-repeat mode is selected, the testing process automatically stops when all the tests have been per- There are several ways to run the Built-In Test, including: formed. If the continuous repeat mode is selected, you will have to manually stop the testing process by press- 1.
  • Page 29 Troubleshooting A. SINGLE looping performs all the tests in the speci- Again, the number to the left is the measured value, fied series. The instrument displays the number of and the number to the right is the test number. the test being run. If a failure occurs, an asterisk (*) 8.

  • Page 30: Built-In Test Documentation

    Troubleshooting 2.11 Built-In test documentation The following paragraphs provide a detailed description of each Built-In Test. Refer to para- graph 2.10 for basic information on how to use the Built-In Tests. The following documentation is provided for each Built-In Test: 1.

  • Page 31: Memory Element Tests

    Troubleshooting 2.11.1 Memory element tests These tests check the EPROM, RAM, and EEPROM memory circuits of the Model 2002. Test 100.1 — EPROM Type Pass/fail Fault message Checksum error Description All ROM bytes (except checksum bytes) are read, a checksum is calculated and compared to the stored checksum.

  • Page 32: Digital I/O Tests

    2.11.2 Digital I/O tests The Digital I/O port on the Model 2002 consists of four open collector outputs and one TTL- level input. Outputs originate from Port A of the 68302 microprocessor (U631), lines PA4 through PA7. PA4 drives Output #1, PA5 drives Output #2, PA6 drives Output #3 and PA7 drives Output #4.

  • Page 33: Ieee-488 Bus Tests

    2.11.3 IEEE-488 bus tests The IEEE-488 interface in the Model 2002 consists of the 9914 GPIA chip (U622) and the 75160 (U621) and 75161 (U623) bus drivers. The 75160 buffers the data lines (DIO1-DIO8), and the 75161 buffers the bus handshake lines and other control signals. The circuitry to test these components is contained in the 5064 ASIC (U618).

  • Page 34: Triggers Tests

    System trigger inputs are normally pulled up to 5V through the protection diodes and 5.1k Ω re- Description sistors (CR611-CR616, R648-R650 and R655-R657). The Model 2002 can generate a trigger on any of the six trigger bus inputs by turning on the appropriate FET (Q602-Q607). These FETs are controlled by system trigger outputs (STO1-STO6) of the 5064 ASIC (U618).
  • Page 35 Open IEEE-488 GET Description Trigger 8 (STI8) is set up as an input, and the 9914 (U622) is then programmed to generate a GET signal. Drawing reference Digital Board; 2002-140 Components U618 and U622. Test 105.11 through 105.18 — Trigger shorts Type...

  • Page 36: A/D Converter Tests

    200 series tests. Once proper operation of the A/D can be determined, the software will convert the counts into voltage values. If the A/D cannot make this measurement, all BIT tests will fail. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Components U816, analog-to-digital conversion circuitry.
  • Page 37 50 counts or less. Failing this test indicates A/D buffer noise or A/D converter circuit noise. Drawing reference Analog Board; 2002-140 A/D Converter; 2002-160 Components A/D buffer or converter noise, power supply or reference supply noise.
  • Page 38 ADGND. ADGND is routed to A/D_IN through the parallel combination of R285 and R286. Common is the input to A/D_IN. Zero reading is acquired and stored for Testcal. This test is performed by measuring for 0V at A/D_IN. Drawing reference Analog Board; 2002-100 Components Switching paths for signals and A/D converter. Bit patterns...
  • Page 39 201.1, 201.2 to determine the proper operation and linearity of the A/D converter. Drawing reference Analog Board; 2002-100 Components Reference circuit, the A/D converter, or the signal paths routing the values to components the A/D.

  • Page 40: Integration Tests

    ADGND. ADGND is routed to A/D_IN through the parallel combination of R285 and R286. Common is the input to A/D_IN. A zero reading is acquired and stored as baseline value for test 202.2. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Bit patterns Bit pattern* Register —U811—...
  • Page 41 REFHI (REFBUF) and REFLO (ADGND). The A/D is triggered and the REFHI reading is acquired and compared to a calculated value based on the previous reading. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Components Shift registers that set up the I15 through I0 levels, open or shorted lines, or components U816.
  • Page 42 Components Shift registers that set up the I15 through I0 levels, open or shorted lines components associated with the I lines, or U816. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Bit patterns Bit pattern* Register —U811—...
  • Page 43 Integration time is set up with I13 and I0 high and all other I lines low. This test used the same circuit setup as test 202.1. A zero reading is acquired and stored as baseline value for test 202.6. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Bit patterns...
  • Page 44 Integration time is set up with I12 and I0 high and all other I lines low. This test uses the same circuit setup as test 202.1. A zero reading is acquired and stored as baseline value for test 202.8. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Bit patterns...
  • Page 45 202.1. A reading is acquired and compared to a calculated value based on the previous reading. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Components Shift registers that set up the I15 through I0 levels, open or shorted lines components associated with the I lines, or U816.
  • Page 46 202.1. A reading is acquired and compared to a calculated value based on the previous reading. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Components Shift registers that set up the I15 through I0 levels, open or shorted lines components associated with the I lines, or U816.
  • Page 47 Integration time is set up with I10 and I0 high and all other I lines low. This test uses the same circuit setup as test 202.1. A zero reading is acquired and stored as baseline value for test 202.12. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Bit patterns...
  • Page 48 Integration time is set up with I9 and I0 high and all other I lines low. This test uses the same circuit setup as test 202.1. A zero reading is acquired and stored as baseline value for test 202.14. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Bit patterns...
  • Page 49 202.1. A reading is acquired and compared to a calculated value based on the previous reading. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Components Shift registers that set up the I15 through I0 levels, open or shorted lines associated with the I lines, or U816.
  • Page 50 202.1. A reading is acquired and compared to a calculated value based on the previous reading. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Components Shift registers that set up the I15 through I0 levels, open or shorted lines associated with the I lines, or U816.
  • Page 51 Integration time is set up with I7 and I0 high and all other I lines low. This test uses the same circuit setup as test 202.1. A zero reading is acquired and stored as baseline value for test 202.18. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Bit patterns...
  • Page 52 Integration time is set up with I6 and I0 high and all other I lines low. This test uses the same circuit setup as 202.1. Zero reading is acquired and stored as baseline value for test 202.20. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Bit patterns...
  • Page 53 202.1. A reading is acquired and compared to a calculated value based on the previous reading. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Components Shift registers that set up the I15 through I0 levels, open or shorted lines associated with the I lines, or U816.
  • Page 54 202.1. A reading is acquired and compared to a calculated value based on the previous reading. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Components Shift registers that set up the I15 through I0 levels, open or shorted lines associated with the I lines, or U816.
  • Page 55 Integration time is set up with I4 and I0 high and all other I lines low. This test uses the same circuit setup as 202.1. A zero reading is acquired and stored as a baseline value for test 202.24. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Bit patterns...
  • Page 56 Integration time is set up with I3 and I0 high and all other I lines low. This test uses the same circuit setup as test 202.1. A zero reading is acquired and stored as baseline value for test 202.26. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Bit patterns...
  • Page 57 202.1. A reading is acquired and compared to a calculated value based on the previous reading. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Components Shift registers that set up the I15 through I0 levels, open or shorted lines associated with the I lines, or U816.
  • Page 58 202.1. A reading is acquired and compared to a calculated value based on the previous reading. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Components Shift registers that set up the I15 through I0 levels, open or shorted lines associated with the I lines, or U816.
  • Page 59 Integration time is set up with I1 and I0 high and all other I lines low. This test uses the same circuit setup as test 202.1. A zero reading is acquired and stored as baseline value for test 202.30. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Bit patterns...
  • Page 60 Integration time is set up with I0 high and all other I lines low. This test uses the same circuit setup as test 202.1. A zero reading is acquired and stored as baseline value for test 202.32. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Bit patterns...
  • Page 61 202.1. A reading is acquired and compared to a calculated value based on the pre- vious reading. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Shift registers that set up the I15 through I0 levels, open or shorted lines associated with the I lines, or U816.

  • Page 62: A/D Multiplexer Tests

    U226. The X1 gain is achieved by closing U227 pins 2 to 3 with /X1 low. R274 is in the feedback path of U226. The typical reference voltage is actually 7.2V. Components U219, U226, U227 and associated circuitry. Drawing reference Analog Board; 2002-100 Bit patterns Bit pattern* Register —U811—...
  • Page 63 R285 and R286. Common is the input to A/D_IN. Common is switched through R259 and U222 pin 4 to pin 3 of U226. Drawing reference Analog Board; 2002-100 Components U222, U226, U227, U253, and associated components.

  • Page 64: Temperature Sensor Test

    For the purpose of this test, the limits of the measurement are 400mV ±400mV. These limits account for the entire specified range of operating environments. Drawing reference Analog Board; 2002-100 Components U205 and associated components. Bit patterns...

  • Page 65: A/D Converter Ground Multiplexer Tests

    2 to 3 with /X1 low. R274 is in the feedback path of U226. Pin 3 of U226 is also pulled to common through U222 pin 4 and R259. Drawing reference Analog Board; 2002-100 Components U226, U227, U242, U253 and associated components.
  • Page 66 X1 gain is achieved by closing U227 pins 2 to 3 with /X1 low. R274 is in the feedback path of U226. Pin 3 of U226 is also pulled to common through U222 pin 4 and R259. Drawing reference Analog Board; 2002-100 Components U222, U226,U227, U242, U253, and associated components. Bit patterns...
  • Page 67 X1 gain is achieved by closing U227 pins 2 to 3 with /X1 low. R274 is in the feedback path of U226. Pin 3 of U226 is also pulled to common through U222 pin 4 and R259. Drawing reference Analog Board; 2002-100 Components U226, U227, U244, U253, and associated components.

  • Page 68: Input Buffer Tests

    U245 input buffer (including the U249 servo). The input buff- er output, BSCOM, goes through Q207 and Q208 to pin 3 of U226. The A/D MUX gain is X1. Drawing reference Analog Board; 2002-100 Components U226, U244, U245, and associated components.

  • Page 69: Open-Circuit Ohms Tests

    K201, R334 and R342. This point is the HI input terminal to the DMM. This signal is then switched through the Q246, Q245, Q244 path to BUFFIN and then to A/D_IN as in test 303.1. Drawing reference Analog Board; 2002-100 Components U219, U220, U223, U233, U254, U255, and associated components.
  • Page 70 U233 pin 3. R276 is used as a voltage divider, but R276 is not an integral part of this test. Q214 is off, and the ohms current flows through CR214 to LO. Drawing reference Analog Board; 2002-100 Components U219, U220, U223, U233, U254, U255, and associated components.

  • Page 71: Range Multiplexer Tests

    7 to pin 3 of U226. X1 gain is achieved by closing U227 pins 2 to 3 with /X1 low. R274 is in the feedback path of U226. Drawing reference Analog Board; 2002-100 Components Q201, U217, U222, U226, and associated components.
  • Page 72 U217 is a unity-gain buffer, 0V also appears at R261, and U222 switches pin 7 to pin 3 of U226. X1 gain is achieved by closing U227 pins 2 to 3 with /X1 low, and R274 is in the feedback path of U226. Drawing reference Analog Board; 2002-100 Components U217, U222, U226, and associated components. Bit patterns...
  • Page 73 3V also appears at R261, and U222 switches pin 7 to pin 3 of U226. X1 gain is achieved by closing U227 pins 2 to 3 with /X1 low, and R274 is in the feedback path of U226. Drawing reference Analog Board; 2002-100 Components Q205, U217, U222, U226, U227, and associated components.

  • Page 74: Ohms Tests

    The current then flows through the 100k Ω leg through Q226 and U244 pin 11 to pin 10 to common. The voltage at BUFFIN is applied to the input buffer to BSCOM and to U226, which is configured for X1 gain. Drawing reference Analog Board; 2002-100 Components U220, U223, U226, U232, and associated components. Bit patterns...
  • Page 75 U222 pin 7. The U222 control lines are configured to switch the pin 7 input to the U222 output and to the A/D buffer in the X1 configuration. Drawing reference Analog Board; 2002-100 Components U222, U231, U244, and associated components.

  • Page 76: 100:1 Input Divider Test

    The 6V open-circuit ohms voltage is divided by 100 and is sensed through Q242 to BUFFIN, through the input buffer then to A/D_IN. The A/D MUX is configured for X50 gain. Drawing reference Analog Board; 2002-100 Components U223, U232, U233, and associated components.

  • Page 77: Overload Tests

    A/D board at J1026 pin 15. There is no A/D measurement for this test. The pass/fail criteria is based on the value of the /OVLD_HI bit. Drawing reference Analog Board; 2002-100 Components U214, U222, U226, and associated components.
  • Page 78 U201, and serially input to the A/D board at J1026 pin 15. There is no A/D mea- surement for this test. The pass/fail criteria is based on the value of the /OVLD_OHM bit. Drawing reference Analog Board; 2002-100 Components U220, U223, U232, U233, and associated components.
  • Page 79 A/D board at J1026 pin 15. There is no A/D measurement for this test. The pass/fail criteria is based on the value of the /OVLD_OHM bit. Drawing reference Analog Board; 2002-100 Components U220, U223, U232, U233, and associated components.

  • Page 80: Calibration/Frequency Compensation Dac Tests

    U414 and is routed out pin 8. It goes to buffer U403, through R462 (where the line is now called ACV/A), through A/D MUX U222 to the U226 A/D buffer, which is set up for X1 gain. Drawing reference Analog Board; 2002-100 Components U403, U430, U433, and associated components. Bit patterns...
  • Page 81 Fault message DAC output not 0.001V Description This test is the same as test 400.1 except that U433 (DAC B) is configured for 0V. Drawing reference Analog Board; 2002-100 Components U403, U430, U433, and associated components. Bit patterns Bit pattern* Register —U811—...
  • Page 82 DAC output not +4.48V Description This test is the same as test 400.1 except that U433 (DAC B) is configured for a 4.48V output. Drawing reference Analog Board; 2002-100 Components U403, U430, U433, and associated components. Bit patterns Bit pattern* Register —U811—...

  • Page 83: Regulator And Switching Tests

    U414 pin 8 and follows the same path to the A/D buffer as the 400 level tests. U226 is set up for X1 gain. Drawing reference Analog Board; 2002-100 Components U403, U414, U418, and associated components.
  • Page 84 Fault message Ground switch Description COMMON at pin 9 of U414 is multiplexed to pin 8 and measured as in the previous 400 level tests. Drawing reference Analog Board; 2002-100 Components U414 and associated components Bit patterns Bit pattern* Register —U811—...

  • Page 85: Absolute Value Circuit X1 Gain Tests

    U419 to pin 12 of the U414 multiplexer. The output of the multiplexer is tied to the A/D through buffer U403, ACV/A input to U222, and the A/D buffer in the X1 gain configuration. Drawing reference Analog Board; 2002-100 Components U403, U417, U418, U419, U428, U430, U433, and associated components.
  • Page 86 U417, R453, U410, Q404, and U419 to pin 12 of multiplexer U414. The output of U414 is tied to the A/D through buffer U403, ACV/A input to U222, and the A/D buffer in X1 gain configu- ration. Drawing reference Analog Board; 2002-100 Components U403, U414, U417, U419, U428, U430, U433, and associated components. Bit patterns...
  • Page 87 DAC U433 and op amp pair U430 are set up to generate +2.33 VDC at PRECOMP+. This signal follows the same path as test 404.3. Drawing reference Analog Board; 2002-100 Components U403, U414, U417, U419, U428, U430, U433, and associated components.

  • Page 88: Absolute Value Circuit, X10 Gain Tests

    FWR that will be set for X10 gain in test 405.2. In this manner, the applied value to the X10 FWR and the output value can be compared to check for FWR accuracy. Components Analog Board; 2002-100 Bit patterns Bit pattern* Register —U811—...
  • Page 89 DAC U433 and op amp pair U430 are set up to generate +0.190 VDC at PRECOMP+. This sig- nal follows the same path as test 405.1. This test has the same purpose as test 405.1, but the new test value is used for test 405.4. Components Analog Board; 2002-100 Bit patterns Bit pattern* Register —U811—...
  • Page 90 DAC U433 and op amp pair U430 are set up to generate -0.210 VDC at PRECOMP+. This signal follows the same path as test 405.1. This test has the same purpose as test 405.1, but the new test value is used for test 405.6. Drawing reference Analog Board; 2002-100 Bit patterns Bit pattern* Register —U811—...
  • Page 91 A/D through buffer U403, ACV/A input to U222, and the A/D buffer gain is X1. Drawing reference Analog Board; 2002-100 Components U403, U408, U412, U414, U417, U419, U430, U433, and associated components.
  • Page 92 DAC U433 and op amp pair U430 are set up to generate -0.490 VDC at PRECOMP+. This signal follows the same path as test 405.6. Drawing reference Analog Board; 2002-100 Components U403, U408, U412, U414, U417, U419, U430, U433, and associated components.

  • Page 93: Sample And Hold Tests

    406.2 and 406.3. In this manner, the applied value to the circuit and the output value (SELFTEST OUT) can be compared to check for circuit accuracy in test phase 406.6. Drawing reference Analog Board; 2002-100 Bit patterns Bit pattern* Register —U811—...
  • Page 94 Fault message None Description This test is the same as test 406.2 except that the value is stored for use in comparison calculation in test phase 406.6. Drawing reference Analog Board; 2002-100 Bit patterns Bit pattern* Register —U811— —U810— —U809—...
  • Page 95 Troubleshooting and the output value (SELFTEST OUT) can be compared to check for circuit accuracy in test phase 406.6. Drawing reference Analog Board; 2002-100 Bit patterns Bit pattern* Register —U811— —U810— —U809— AD_STB 00001101 00000011 11100111 —U206— —U207— MUX_STB 01110000 11001111 —U224—...
  • Page 96 The measurement compares the actual difference in the DAC voltages 406.1- 406.4 with that found via the sample and hold circuit tests 406.3-406.6. Drawing reference Analog Board; 2002-100 Components Q409, U402, U426, U428, and associated components. Bit patterns...

  • Page 97: Front End X1, /100, /500 Tests

    U410, Q404, and U419 to pin 12 of U414. The output of U414 is tied to the A/D buffer through buffer U403, R434, R462, and U222. The A/D buffer is configured for X1 gain. Drawing reference Analog Board; 2002-100 Components Q418, U410, U417, U419, U420, U423, and associated components.
  • Page 98 U414 is tied to the A/D buffer through buffer U403, R434, R462, and U222. The A/D buff- er is configured for X1 gain. Drawing reference Analog Board; 2002-100 Components Q418, U410, U417, U419, U420, U423, and associated components.

  • Page 99: 200 Frequency Compensation Tests

    The divided voltage pin 4 is tied to AC buffer Q418 and U423 through U428 and Q422. The sig- nal AMP IN is tied through U425, U426, to Q510. This phase sets up the conditions for the next phase; there is no measurement in this phase. Drawing reference Analog Board; 2002-100 Bit patterns Bit pattern* Register —U811—...
  • Page 100 Q409 (SELFTEST OUT) is tied to U414 pin 11. The output of U414 is tied to the A/D buffer through buffer U403, R434, R462, and U222. The A/D buffer is configured in X1 gain. This measurement is saved and used in a comparison in test 408.6. Drawing reference Analog Board; 2002-100 Bit patterns Bit pattern* Register —U811—...
  • Page 101 Test 408.4 — Correction factor Type Circuit Exercise Fault message None Description This test is the same as test 408.3 except that no measurement is taken. Drawing reference Analog Board; 2002-100 Bit patterns Bit pattern* Register —U811— —U810— —U809— AD_STB...
  • Page 102 Pass/Fail Fault message 200V range compensation Description Same as test 408.2. Measure the output at A/D IN. Drawing reference Analog Board; 2002-100 Components C459, C461, Q418, Q422, U423, U425, U426, U433 and associated components. Bit patterns Bit pattern* Register —U811—...

  • Page 103: 750 Frequency Compensation Tests

    The signal AMP IN is tied to the circuit through U425, U426, to Q414. This phase sets up the conditions for the next phase; there is no measurement in this phase. Drawing reference Analog Board; 2002-100 Bit patterns Bit pattern* Register —U811—...
  • Page 104 In this phase, DAC A is programmed with 0s, and the output at pin 2 is tied to C463. The rest of this test is the same as Test 408.3. Drawing reference Analog Board; 2002-100 Bit patterns Bit pattern* Register —U811—...
  • Page 105 Test 409.4 — Correction factor Type Circuit Exercise Fault message None Description This test is the same as test 408.3 except that no measurement is taken. Drawing reference Analog Board; 2002-100 Bit patterns Bit pattern* Register —U811— —U810— —U809— AD_STB...
  • Page 106 Pass/Fail Fault message 750V range compensation Description Same as Test 409.2. Measure the output as A/D IN. Drawing reference Analog Board; 2002-100 Components C460, C463, Q418, Q422, U423, U425, U426, U420, and associated components. Bit patterns Bit pattern* Register —U811—...

  • Page 107: True Rms Converter And Filter Tests

    U420. The output of U420 is tied to U414 pin 6 through R219, and the output of U414 is tied to the A/D buffer through buffer U403, R434, R462, and U222. The A/D buffer is config- ured for X1 gain. Drawing reference Analog Board; 2002-100 Components U410, U417, U420, U423, and associated components. Bit patterns...
  • Page 108 A/D buffer through buffer U403, R434, R462, and U222. The A/D buffer is config- ured for X1 gain. Drawing reference Analog Board; 2002-100 Components U410, U412, U417, U419, U420, U423, U426, and associated components. Bit patterns...

  • Page 109: Frequency Tests

    U222. U222 is set up to switch ACV/A input to the A/D buffer U226. U226 is set up for X1 gain through U227 pin 2 to 3 with /X1 pin 1 low. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 2-96...
  • Page 110 This test uses the same setup as test 412.1 except that shift register U811 on the A/D board is configured to set up the U816 ASIC to read frequency. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Bit patterns Bit pattern* Register —U811—...
  • Page 111 None Description This test uses the same setup as test 412.1 except that shift register U811 on the A/D sets up the U816 ASIC to read frequency. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Bit patterns Bit pattern* Register —U811—...
  • Page 112 This test uses the same setup as test 412.1 except that the SELFTEST line is toggled to make Q425 switch. Tests 412.4 and 412.5 are repeated 85 times. The switching is read as a frequency. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Bit patterns...
  • Page 113 None Description This test uses the same setup as test 412.1 except that the SELFTEST line is toggled through one more iteration to finish the frequency measurement. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Bit patterns Bit pattern* Register —U811—...
  • Page 114 This test uses the same setup as test 412.1 except that shift register U811 on the A/D board sets up the U816 ASIC to finish reading frequency and transfer the internal counts to the digital board. Drawing reference Analog Board; 2002-100 A/D Converter; 2002-160 Bit patterns Bit pattern* Register —U811—...

  • Page 115: Amps/Low Ohms Tests

    DCA. DCA is switched through U222 to the A/D MUX U226, and the gain is X1. NOTE: INPUT HI and AMPS must be externally jumpered together to run this test. Drawing reference Analog Board; 2002-100 Components U220, U222, U223, U225, U226, U232, U233, and associated components.
  • Page 116 U222 to the A/D multiplexer U226, and the gain is X1. NOTE: INPUT HI and AMPS must be externally jumpered to run this test. Drawing reference Analog Board; 2002-100 Components U220, U222, U223, U225, U226, U232, U233, and associated components.
  • Page 117 U222 to the A/D MUX U226, and the gain is X1. NOTE: INPUT HI and AMPS must be externally jumpered to run this test. Drawing reference Analog Board; 2002-100 Components U220, U222, U223, U225, U226, U232, U233, and associated components.
  • Page 118 U222 to the A/D MUX U226, and the gain is X50. NOTE: INPUT HI and AMPS must be externally jumpered to run this test. Drawing reference Analog Board; 2002-100 Components U220, U222, U223, U225, U226, U232, U233, and associated components.
  • Page 119 U222 to the A/D MUX U226, and the gain is X50. NOTE: INPUT LO and AMPS must be externally jumpered to run this test. Drawing reference Analog Board; 2002-100 Components U220, U222, U223, U225, U226, U232, U233, and associated components.

  • Page 120: Amps Protection Tests

    A/D MUX U226, and the gain is X1. NOTE: INPUT HI and AMPS must be externally jumpered to run this test. Drawing reference Analog Board; 2002-100 Components U220, U222, U223, U225, U226, U232, U233, and associated components. Bit patterns...
  • Page 121 AMPBOOT line. AMPBOOT is switched through U222 to the A/D MUX U226, and the gain is X1. NOTE: INPUT HI and AMPS must be externally jumpered to run this test. Drawing reference Analog Board; 2002-100 Components U220, U222, U223, U225, U226, U232, U233, and associated components. Bit patterns...

  • Page 122: Aca Switch Test

    MUX is tied to the A/D through buffer U403, ACV/A input to U222, and the A/D buffer in X1 gain configuration. NOTE: INPUT HI and AMPS must be externally jumpered to run this test. Drawing reference Analog Board; 2002-100 Components U410, U411, U413, U414, U419, and associated components. Bit patterns...

  • Page 123: Ohms Sense Tests

    Q207 and Q208 to the A/D MUX U226. The gain is X1. NOTE: The INPUTS and SENSE jacks must be externally shorted together to run this test. Drawing reference Analog Board; 2002-100 Components Q207, Q208, Q231, Q232, Q243, and associated components.
  • Page 124 15 to 14, to the ADGND MUX U253, then to the A/D MUX at U226. Common is routed through U222 S1 to U226 pin 3. A/D MUX gain is X1. NOTE: The INPUTS and SENSE jacks must be externally shorted together to run this test. Drawing reference Analog Board; 2002-100 Components R360, U242, and associated components. Bit patterns...
  • Page 125 Troubleshooting 2-112...

  • Page 126: Disassembly

    The information in this section explains how to disassemble Model 2002. the Model 2002. Also discussed are handling and cleaning considerations as well as the procedure to change the main CPU firmware in the event of an upgrade. This section is or-...

  • Page 127: Special Handling Of Static-Sensitive Devices

    • After cleaning, the board should be allowed to dry in a 50°C low-humidity environment for several hours. To remove the case cover, refer to drawing 2002-054 (at the Special handling of static-sensitive de- end of this section), and perform the following steps: vices 1.

  • Page 128: Pc-Board Removal

    The digital board is removed through the bottom of the chas- board rests on three stand-offs. Each standoff has a re- sis (see drawing 2002-053). Note that the power switch push- taining clip to hold the board securely in place. Gently rod need not be removed in order to remove the digital board.

  • Page 129: Front Panel Disassembly

    052 shows how the front panel separates from the chassis, soldered from the analog board. The solder connection and drawing 2002-040 shows an exploded view of the front for this white/blue wire is located next to the INPUTS panel assembly.

  • Page 130: Cooling Fan Removal

    U638) located on the digital board. (See the digital board 3. Remove Display Board: The display board is held in component layout drawing 2002-140 at the end of Section place by a PC board stop. This stop is simply a plastic bar that runs along the bottom edge of the display board.

  • Page 131: Instrument Re-Assembly

    Make sure that all parts are disassembly and re-assembly of the instrument. Also, the properly seated and secured, and that all connections are Keithley part numbers for most mechanical parts are provid- properly made. To ensure proper operation, shields must be ed in these drawings.

  • Page 132: Replaceable Parts

    2. Complete the service form at the back of this manual, and include it with the instrument. The following parts lists for the Model 2002 are shown in Ta- 3. Carefully pack the instrument in the original packing bles 4-1 to 4-5. For part numbers to the various mechanical carton.
  • Page 133 IC-954 U819 IC, GND-SENSE, 12NS COMPARATOR, LT1116 IC-908 U820 IC, QUAD D FLIP FLOP W/CLK, RESET 72HC175 IC-923 VR801, 802 DIODE, ZENER, 6.2V, MMS26V2 SOD-123 DZ-97 Y801 OSCILLATOR HIGH SPEED CMOS 12MHZ CR-37 * Order revision level. For example: 2002-803-A03...
  • Page 134 Replaceable Parts Table 4-2 Model 2002 display board, parts list Keithley part Circuit desig. Description number DISPLAY BOARD ASSEMBLY 2002-110 C901 CAP, 22UF, 20%, 6.3, TANTALUM C-417-22 C902, 904, 907, 908, 910 CAP, .1UF, 20%, 100V, CERAMIC C-436-.1 C903, 905, 906, 909, 911 CAP, .1UF, 20%, 50V, CERAMIC...
  • Page 135 Replaceable Parts Table 4-3 Model 2002 analog board parts list Keithley part Circuit desig. Description number ANALOG ASSEMBLY 2002-100 CONN, TEST POINT CS-553 CRIMP CONTACT ROUND CS-760 FUSE HOLDER (FOR F101, 102) FH-32 C101, 103, 115, 402 CAP, 10UF, 20%, 25V, TANTALUM...
  • Page 136 Replaceable Parts Table 4-3 Model 2002 analog board parts list (cont.) Keithley part Circuit desig. Description number C461 CAP, 91PF, 1%, 300V, MICA C-474-91P C463 CAP, 270PF, 1%, 300V, MICA C-462-270P C464 CAP, .1UF, 20%, 1000V, MET POLYCARBONATE C-490-.1 CR101...
  • Page 137 Replaceable Parts Table 4-3 Model 2002 analog board parts list (cont.) Keithley part Circuit desig. Description number Q208 TRANS, N CHANNEL JFET (TO-92) TG-225 Q210, 233, 239 TRANS, NPN COMP SILICON AMP, 2N5089 TG-62-1 Q211 TRANS, P-CHANNEL MOSFET, 3N163 TG-126...
  • Page 138 Replaceable Parts Table 4-3 Model 2002 analog board parts list (cont.) Keithley part Circuit desig. Description number R207-210, 249 RES, 270, 5%, 250MW, METAL FILM R-376-270 R211, 245-248, 274, 284, 298, 317, 330, RES, 1K, 1%, 125MW, METAL FILM R-391-1K...
  • Page 139 Replaceable Parts Table 4-3 Model 2002 analog board parts list (cont.) Keithley part Circuit desig. Description number R342 RES, 1.5K, 5%, 250MW, METAL FILM R-376-1.5K R350, 380 RES, 18.7, 1%, 125MW, METAL FILM R-391-18.7 R359-361 RES, 5K, .1%, WIREWOUND R-249-5K R362 RES, .1, 1%, 2W, 4-TERMINAL MOLDED...
  • Page 140 Replaceable Parts Table 4-3 Model 2002 analog board parts list (cont.) Keithley part Circuit desig. Description number U101, 237, 421 IC, MOSFET DRIVER, TLP590A IC-812 U102, 405 IC, VOLT COMPARATOR, LM311M IC-776 U103, 104 IC, OPTO-COUPLER, HIGH EMI, H11AV1A IC-845...
  • Page 141 Replaceable Parts Table 4-3 Model 2002 analog board parts list (cont.) Keithley part Circuit desig. Description number V243 IC, TRI-2CH MULTI-DEMUX, 4053 IC-770 V403, 422, 424, 425 IC, 20V OP-AMP, LT1097S8 IC-767 VR101 DIODE, ZENER 22V, BZX84C22 DZ-86 VR102, 104, 206, 211, 213 DIODE, ZENER 6.2V, BZX84B6V2...
  • Page 142 Replaceable Parts Table 4-4 Model 2002 digital board, parts list Keithley part Circuit desig. Description number CONN, BERG CS-339 CONN, MALE 3 PIN CS-612-1 DIGITAL ASSEMBLY 2002-140 C602, 603, 605-607, 620, 636-640, CAP, .1UF, 20%, 50V, CERAMIC C-418-.1 665-667 C604, 661 CAP, .1UF, 20%, 50V, CERAMIC...
  • Page 143 2002-803-* U638 PROGRAMMED, IC, 4M, CMOS EPROM, AT27C040-15DC 2002-804-* VR602, 603 DIODE, ZENER 4.7V, IN4732A DZ-67 W605, 606 CONN, 3 PIN CS-339-3 W606 CONNECTOR, JUMPER CS-476 Y602 CRYSTAL, 16MHZ CR-30-16M * Order correct firmware revision number. For example: 2002-803-A03 4-12...
  • Page 144 Replaceable Parts Table 4-5 Model 2002 miscellaneous, parts list Keithley part Circuit desig. Description number 1/4X1/4X.2 PAD, THERMAL HS-46A BANANA JACK, PUSH-IN, BLACK BJ-13-0 BANANA JACK, PUSH-IN, RED BJ-13-2 BEZEL, REAR 428-303D CHASSIS 2001-303 CHOKE CH-58-1A COVER 2001-360C DISK PROGRAMMING...

  • Page 145: Specifications

    Specifications...
  • Page 146 Index Numeric / symbol 100:1 input divider test 2-63 Calibration/frequency compensation Handling and cleaning precautions 3-1 20V range multiplexer tests 2-58 DAC tests 2-67 HI/LO voltage control circuit 2-12 /200 frequency compensation tests 2-86 Case cover and shield removal 3-2 /750 frequency compensation tests 2-90 Case cover removal 3-2 Character set test 2-3...
  • Page 147 Normal operation bit patterns 2-3 Rear AMPS input fuse 1-3 Using Built-in Test 2-15 Regulator and switching tests 2-70 Repair considerations 2-2 Replaceable parts 4-1 Routine maintenance 1-1 Ohms sense tests 2-110 Vacuum fluorescent display 2-11 Ohms tests 2-61 Open-circuit ohms tests 2-56 Ordering information 4-1 Overload tests 2-64 Sample and hold tests 2-80...
  • Page 148 Service Form Model No. Serial No. Date 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 Batteries and fuses are OK Front panel operational All ranges or functions are bad...

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