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Troubleshooting

2-95

Bit patterns

Test 411.2 — Filter; variable gain amplifier

Type

Pass/Fail

Fault message

Filter

Description

REFHI is tied to pin 1 of U420 and buffered to form BUFF. BUFF through R493, K403, K401,
input protection, and Q421 is tied to the input buffer Q418 and U423. The buffered BUFF signal
(AMP IN) is tied to the FWR, and, being positive, follows the non-inverting, X1 path R452,
Q412, Q411, U417, R453, U410, Q404, and U419 to the filter through U412. Output of the filter
R435, R446, R447, C433, C434, C432, and U426 is tied to U414 pin 5, 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, U412, U417, U419, U420, U423, U426, and associated components.

Bit patterns

Bit pattern*

Register

—U400—

01011001

—U811—

00001101

—U224—

00010111

—U432—

11000000

—U810—

00000011

—U206—

01110000

—U203—

10001110

—U411—

10111001

—U809—

11100111

—U207—

11001111

—U221—

11101001

—U406—

10101110

AD_STB

MUX_STB

R1_STB

R2_STB

*Bits associated with register IC terminals as follows:
Q

Q

Q

Q

Q

Q

Q

Q

87654321

87654321

87654321

87654321

IC pins: Q8=11, Q7=12, Q6=13, Q5=14, Q4=7, Q3=6, Q2=5, Q1=4.

Bit pattern*

Register

—U400—

01011001

—U811—

00001101

—U224—

00010111

—U432—

10000000

—U810—

00000011

—U206—

01110000

—U203—

10001110

—U411—

11111001

—U809—

11100111

—U207—

11001111

—U221—

11101001

—U406—

10101110

AD_STB

MUX_STB

R1_STB

R2_STB

*Bits associated with register IC terminals as follows:
Q

Q

Q

Q

Q

Q

Q

Q

87654321

87654321

87654321

87654321

IC pins: Q8=11, Q7=12, Q6=13, Q5=14, Q4=7, Q3=6, Q2=5, Q1=4.

Summary of Contents for 2002

Page 1: ...Model 2002 Multimeter Repair Manual Contains Servicing Information...

Page 2: ...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 INDI RECT SPECIAL INCIDENTAL OR CONSE...

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: ...m bered 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 re...

Page 5: ...voltage is present in any unknown circuit before measuring Users of this product must be protected from electric shock at all times The responsible body must ensure that users are prevented access and...

Page 6: ...result in personal injury or death Always read the associated infor mation very carefully before performing the indicated procedure The CAUTION heading in a manual explains hazards that could damage...

Page 7: ...ontrol register ICs 2 3 2 6 2 Normal operation bit patterns 2 3 2 7 Display board checks 2 5 2 8 Power supply checks 2 5 2 9 Principles of operation 2 6 2 9 1 Block diagrams 2 6 2 9 2 Display board ci...

Page 8: ...2 11 25 Frequency tests 2 96 2 11 26 Amps low ohms tests 2 102 2 11 27 Amps protection tests 2 107 2 11 28 ACA switch test 2 109 2 11 29 Ohms sense tests 2 110 3 Disassembly 3 1 Introduction 3 1 3 2...

Page 9: ...Figure 1 3 Rear AMPS input fuse location 1 3 2 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 Fig...

Page 10: ...oting 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 2 5 Table 2 5 Display board che...

Page 11: ...nt front and rear before replacing the line fuse The power line fuse is accessible from the rear panel just be low the AC power receptacle see Figure 1 1 Perform the following steps to replace the lin...

Page 12: ...h the type specified in Table 1 2 CAUTION To prevent instrument damage use only the type specified in Table 1 2 3 Re install the fuse carrier Table 1 2 Power line fuse Size Rating Keithley Part No 5 2...

Page 13: ...ndling the filter assembly The filter element is a metal screen with sharp edges that could cause injury if not handled carefully The filter element is made of a rugged metal screen allowing the use o...

Page 14: ...y 2 5 Diagnostics Explains how to use the Diagnostics test mode of the Model 2002 In general Diagnostics locks up the instrument in various states of operation With the instrument in a static state yo...

Page 15: ...trument will lock up 2 4 Front panel tests There are two Front Panel Tests one to test the functionality of the front panel keys and one to test the display In the event of a test failure refer to par...

Page 16: ...summarized in Table 2 1 5 To view A D counts press the right arrow key 6 When finished press EXIT three times to back out of the menu structure and return to the normal measurement mode of operation...

Page 17: ...000 11110000 11110000 11110000 11110000 11110000 01110100 01110100 01110100 01110111 10110111 10110111 11010111 11100111 11101011 11101000 11101000 11101000 20 4 wire 200 4 wire 2k 4 wire 20k 4 wire 2...

Page 18: ...000V DC 01101010 00000000 10100011 00000111 200 A 2A DC 01101010 00000000 10100011 00000111 20 1G 2 wire 01101010 00000000 10100011 00000111 20 2M 4 wire 01101010 00000000 10100011 00000111 200mV AC 2...

Page 19: ...LF TEST MENU selection Digital 5V supply VFD 60V supply Microcontroller RESET line Controller 4MHz clock Control from main processor Key down data sent to main pro cessor Table 2 6 Display board check...

Page 20: ...TRMS AVE PK FREQ Out AC FETS Scanner Control Out Line FREQ In ADC CLK DATA STB TRG O P T O I S O Hardware Trigger Trigger Select Logic ADC Data In CLK DATA STB Control Data Out Trigger Delay Software...

Page 21: ...U102 U105 K101 K102 15V Supply CR113 C112 C113 U107 U109 Bootstrap Supply CR114 CR117 C116 C117 5V Supply CR112 C114 C115 U110 15V COM 15V BS 34V to 38V Common 3 BS 34V to 38V 5V Digital Common Figur...

Page 22: ...ooting 2 9 ROM U637 U638 RAM U635 U636 U608 NVRAM U632 U634 Microprocessor U631 GPIB U621 U623 IEEE 488 Interface A D Control Data A D Interface U614 Trigger Digital I O Figure 2 4 Digital board block...

Page 23: ...e U231 U233 Ohms Ref U230 7V Ref U218 U219 U255 2V Ref U241 AMPS IN Amps Ranging I V Converter R295 R319 R362 Q215 Q217 Q222 Q223 AC Input Buffer Q410 Q415 Q420 Q424 Variable Gain Amplifier U419 U424...

Page 24: ...CR622 doubled C624 C630 CR624 and CR625 and applied to U619 which is a 5V regulator This 5V 5VC is used for the pre regulator circuit The pre regulator circuit monitors the voltage level on C611 usin...

Page 25: ...riven low turning on U104 With U104 and Q105 on 8V will be applied to THR of U106 forcing its output OUT to reset to low With the gate of Q104 low the FET will turn off and open the relay coil cir cui...

Page 26: ...A D Multiplexer MUX A D Buffer 7V Reference X1 Gain 1 75V Reference X5 Gain 0V Reference X50 Gain Temperature Sensor Temperature Sensor A D Ground Multiplexer Signal Zero to A D Ground Reference LO t...

Page 27: ...08 6 200 Frequency Compensation 750 Frequency Compensation Circuit Setup for test 409 2 Step Response for test 409 3 Setup for test 409 5 and Step Read ing for test 409 6 Same as Test 409 3 but no mea...

Page 28: ...cess The instrument displays the number of the test be ing run to the right and the number to the left is the measured value If a failure occurs an asterisk ap pears at the right hand end of the displ...

Page 29: ...e occurs an asterisk ap pears at the right hand end of the display and remains on for the remainder of the tests in the se ries The instrument automatically aborts the testing process after the last t...

Page 30: ...ysis by pressing the INFO key 3 Description Provides a description of the circuit being tested 4 Drawing Reference Identifies the component layout drawing associated with the described circuitry Compo...

Page 31: ...ll fail A unit with faulty memory will probably fail the power on memory test or will lock up intermittently Drawing reference Digital Board 2002 140 Components U635 U636 and associated logic Test 101...

Page 32: ...Port A registers are bidirectional even though in normal use they are programmed only as outputs Diodes and resistors are connected around U612 so that OUT1 feeds back to PA5 OUT2 feeds back to PA6 OU...

Page 33: ...e written to the 9914 U622 Data Out register and the interrupt status register is checked to verify that a Byte Out handshake is completed These tests verify the basic functionality of the 9914 75161...

Page 34: ...off through STO1 and it is verified that this trips the trigger circuitry in the ASIC This test is then repeated for trigger 2 through 6 for tests 105 2 through 105 6 Success indicates proper op erati...

Page 35: ...rs STI2 through STI7 and GET is programmed to toggle in sequence If a trigger is detected at STI1 a short is indicated and the test fails The test is repeated for STI2 through STI8 in tests 105 12 thr...

Page 36: ...scribed in the note above U222 is set up to switch common through R259 and S1 pin 4 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 Also common is swi...

Page 37: ...00 01111011 U811 00001101 U224 00010111 U432 10000000 U810 00010111 U206 01110000 U203 10001110 U411 11111011 U809 01101111 U207 00001111 U221 11101001 U406 00000100 AD_STB MUX_STB R1_STB R2_STB Bits...

Page 38: ...gnal REFBUF is switched through R263 and U222 pin 5 to U226 U226 is set up for X1 gain through U227 pin 2 to 3 with X1 pin 1 low R274 is the feedback path of U226 REFLO is switched through R310 and U2...

Page 39: ...F reading in counts is acquired A calculation is made with the values stored in 201 1 201 2 to determine the proper operation and linearity of the A D converter Drawing reference Analog Board 2002 100...

Page 40: ...cquired The cir cuit setup for zero and 7V reference will be in tests 202 1 and 202 2 The remaining tests will refer to the first two tests HIGH and LOW logic levels refer to 5V and 0V respectively Te...

Page 41: ...red 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 se...

Page 42: ...terns Bit pattern Register U400 01111011 U811 00001101 U224 00010111 U432 10000000 U810 01000000 U206 01110000 U203 10001110 U411 11111011 U809 00000001 U207 00001111 U221 11101001 U406 00000100 AD_ST...

Page 43: ...nd all other I lines low This test uses the same circuit setup as test 202 1 A reading is acquired and compared to a calculated value based on the previous reading Drawing reference Analog Board 2002...

Page 44: ...810 00100000 U206 01110000 U203 10001110 U411 11111011 U809 00000001 U207 00110111 U221 11101001 U406 00000100 AD_STB MUX_STB R1_STB R2_STB Bits associated with register IC terminals as follows Q Q Q...

Page 45: ...it patterns Test 202 9 Baseline for test 202 10 Type Circuit Exercise Fault message None Description Integration time is set up with I11 and I0 high and all other I lines low This test uses the same c...

Page 46: ...terns Bit pattern Register U400 01111011 U811 00001101 U224 00010111 U432 10000000 U810 00001000 U206 01110000 U203 10001110 U411 11111011 U809 00000001 U207 00001111 U221 11101001 U406 00000100 AD_ST...

Page 47: ...0 high and all other I lines low This test uses the same circuit setup as test 202 1 A reading is acquired and compared to a calculated value based on the previous reading Components Shift registers t...

Page 48: ...U810 00000100 U206 01110000 U203 10001110 U411 11111011 U809 00000001 U207 00110111 U221 11101001 U406 00000100 AD_STB MUX_STB R1_STB R2_STB Bits associated with register IC terminals as follows Q Q Q...

Page 49: ...terns Test 202 15 Baseline for test 202 16 Type Circuit Exercise Fault message None Description Integration time is set up with I8 and I0 high and all other I lines low This test uses the same circuit...

Page 50: ...it pattern Register U400 01111011 U811 00001101 U224 00010111 U432 10000000 U810 00000001 U206 01110000 U203 10001110 U411 11111011 U809 00000001 U207 00001111 U221 11101001 U406 00000100 AD_STB MUX_S...

Page 51: ...high and all other I lines low This test uses the same circuit setup as test 202 1 A reading is acquired and compared to a calculated value based on the previous reading Drawing reference Analog Board...

Page 52: ...00000000 U206 01110000 U203 10001110 U411 11111011 U809 10000001 U207 00110111 U221 11101001 U406 00000100 AD_STB MUX_STB R1_STB R2_STB Bits associated with register IC terminals as follows Q Q Q Q Q...

Page 53: ...terns Test 202 21 Baseline for test 202 22 Type Circuit Exercise Fault message None Description Integration time is set up with I5 and I0 high and all other I lines low This test uses the same circuit...

Page 54: ...it pattern Register U400 01111011 U811 00001101 U224 00010111 U432 10000000 U810 00000000 U206 01110000 U203 10001110 U411 11111011 U809 00100001 U207 00001111 U221 11101001 U406 00000100 AD_STB MUX_S...

Page 55: ...gh and all other I lines low This test uses the same circuit setup as test 202 1 A reading is acquired and compared to a calculated value based on the previous reading Drawing reference Analog Board 2...

Page 56: ...U810 00000000 U206 01110000 U203 10001110 U411 11111011 U809 00010001 U207 00110111 U221 11101001 U406 00000100 AD_STB MUX_STB R1_STB R2_STB Bits associated with register IC terminals as follows Q Q Q...

Page 57: ...atterns Test 202 27 Baseline for 202 28 Type Circuit Exercise Fault message None Description Integration time is set up with I2 and I0 high and all other I lines low This test uses the same circuit se...

Page 58: ...it pattern Register U400 01111011 U811 00001101 U224 00010111 U432 10000000 U810 00000000 U206 01110000 U203 10001110 U411 11111011 U809 00000101 U207 00001111 U221 11101001 U406 00000100 AD_STB MUX_S...

Page 59: ...high and all other I lines low This test uses the same circuit setup as test 202 1 A reading is acquired and compared to a calculated value based on the previous reading Drawing reference Analog Board...

Page 60: ...00000000 U206 01110000 U203 10001110 U411 11111011 U809 00000011 U207 00001111 U221 11101001 U406 00000100 AD_STB MUX_STB R1_STB R2_STB Bits associated with register IC terminals as follows Q Q Q Q Q...

Page 61: ...e 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 Bit patterns Bit pattern Register U400 01...

Page 62: ...ched at 600Hz through U230 U235 and buffer U241 along with the 25 duty cycle of the 600Hz clock signal gener ates the 1 75V reference 2VREF 2VREF is switched through R260 and U222 pin 6 to U226 U226 i...

Page 63: ...reference Analog Board 2002 100 Components U222 U226 U227 U253 and associated components Bit patterns Bit pattern Register U400 01111011 U811 00001101 U224 00010111 U432 10000000 U810 00000011 U206 10...

Page 64: ...e A D con verter is therefore dependent on the ambient temperature For the purpose of this test the limits of the measurement are 400mV 400mV These limits account for the entire specified range of ope...

Page 65: ...REFLO to ADGND Description REFLO is switched through R310 and U242 pins 7 to 6 through R311 and to pin 3 of U253 U253 is the buffer for ADGND ADGND buffer with REFLO signal is connected to the bottom...

Page 66: ...onents U222 U226 U227 U242 U253 and associated components Bit patterns Bit pattern Register U400 01111011 U811 00001101 U224 00010111 U432 10000000 U810 00000011 U206 01110000 U203 10001110 U411 11111...

Page 67: ...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 U...

Page 68: ...o BUFFIN BUFFIN goes into the bootstrap supply and 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...

Page 69: ...n this test there is no path provided for current to flow outside of the ohms source In normal operation the current would flow out of the ohms current source from the parallel path of Q211 and Q212 t...

Page 70: ...he ohms current flows through CR214 to LO Drawing reference Analog Board 2002 100 Components U219 U220 U223 U233 U254 U255 and associated components Bit patterns Bit pattern Register U400 01111011 U81...

Page 71: ...222 switches pin 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 U...

Page 72: ...range MUX zero Description Q202 is turned on allowing the 0V common to be applied to the R240 divider Q203 is always on because its gate and source are tied together by R241 0V appears at U217 pin 3 S...

Page 73: ...of U226 Drawing reference Analog Board 2002 100 Components Q205 U217 U222 U226 U227 and associated components Bit patterns Bit pattern Register U400 01111011 U811 00001101 U224 00010111 U432 10000000...

Page 74: ...is switched in with the OHMD line at U223 and U220 U232 pin 10 to 11 switches in R276 basically forming a 5 1 divider between buffered OHMREFHI and REF BUF 5 76V relative to REFBUF or 12 96V relative...

Page 75: ...es 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: ...combination of VR204 and Q214 is sensed by the path that routes through Q213 R322 CR217 K201 R334 and R342 This point is the HI input terminal to the DMM The 10M value described above is the series pa...

Page 77: ...LD lines are latched by U202 parallel loaded into U201 and serially input to theA D board at J1026 pin 15 There is noA D measurement for this test The pass fail criteria is based on the value of the O...

Page 78: ...pin 15 to 14 and switching R288 in parallel with R234 Along with R235 this divider places pin 5 of U215 at 4 5V Since the COMPLIANCE line at 6V is more positive than 4 5V the OVLD_OHM line is pulled...

Page 79: ...the divider in this case is made up of R235 and R234 This divider places pin 5 of U215 at 5 7V Since the COMPLIANCE line at 6 6V is more positive than the 5 7V on OVLD_OHM the line is pulled low at a...

Page 80: ...hich is set up for X1 gain Drawing reference Analog Board 2002 100 Components U403 U430 U433 and associated components Bit patterns Test 400 2 DAC output set to 2 15V Type Pass Fail Fault message DAC...

Page 81: ...pattern Register U400 01011011 U811 00001101 U224 00010111 U432 10001100 U810 00000011 U206 01110000 U203 10001110 U411 11111011 U809 11100111 U207 11001111 U221 11101001 U406 00001100 AD_STB MUX_STB...

Page 82: ...0011 U206 01110000 U203 10001110 U411 11111011 U809 11100111 U207 11001111 U221 11101001 U406 00001100 AD_STB MUX_STB R1_STB R2_STB Bits associated with register IC terminals as follows Q Q Q Q Q Q Q...

Page 83: ...uency switch U425 FREQ control line pulled low is verified by dividing the PRECOMP voltage by the ratio of R491 and R440 The on resistance of U425 about 25 between pins 2 and 3 must also be added to R...

Page 84: ...11111011 U809 11100111 U207 11001111 U221 11101001 U406 01001100 AD_STB MUX_STB R1_STB R2_STB Bits associated with register IC terminals as follows Q Q Q Q Q Q Q Q 87654321 87654321 87654321 87654321...

Page 85: ...e 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 Comp...

Page 86: ...g reference Analog Board 2002 100 Components U403 U414 U417 U419 U428 U430 U433 and associated components Bit patterns Bit pattern Register U400 01011100 U811 00001101 U224 00010111 U432 01001100 U810...

Page 87: ...002 100 Components U403 U414 U417 U419 U428 U430 U433 and associated components Bit patterns Bit pattern Register U400 01011100 U811 00001101 U224 00010111 U432 10111000 U810 00000011 U206 01110000 U2...

Page 88: ...and U412 ACF is tied to AMP IN through U428 Q422 and ACV buffer AMP IN is tied to the inverting and non inverting paths of the FWR NETOUT from U417 in the non inverting path is monitored by the ZERO C...

Page 89: ...same path as test 405 2 Drawing reference Analog Board 2002 100 Bit pattern Register U400 01011100 U811 00001101 U224 00010111 U432 10001101 U810 00000011 U206 01110000 U203 10001110 U411 11111111 U80...

Page 90: ...0 U811 00001101 U224 00010111 U432 10000101 U810 00000011 U206 01110000 U203 10001110 U411 11111111 U809 11100111 U207 11001111 U221 11101001 U406 01001111 AD_STB MUX_STB R1_STB R2_STB Bits associated...

Page 91: ...Drawing reference Analog Board 2002 100 Components U403 U408 U412 U414 U417 U419 U430 U433 and associated components Bit patterns Test 405 7 Large negative DAC V for X10 gain comparison Type Circuit...

Page 92: ...10 00000011 U206 01110000 U203 10001110 U411 11011111 U809 11100111 U207 11001111 U221 11101001 U406 01001111 AD_STB MUX_STB R1_STB R2_STB Bits associated with register IC terminals as follows Q Q Q Q...

Page 93: ...C U433 and op amp pair U430 are set up to generate 1 13 VDC at PRECOMP and tied to ACF through R491 and U412 ACF is buffered to AMP IN through U428 Q422 and ACV buff er AMP IN is tied through U425 to...

Page 94: ...lue of the DAC voltage is measured and stored This value will also be applied to the circuit in tests 406 5 and 406 6 In this manner the applied value to the circuit Bit pattern Register U400 01011101...

Page 95: ...ed to multiplexer U414 pin 11 The multiplexer output is tied to the A D through buffer U403 ACV A input to U222 and the A D buffer in X1 gain configuration Drawing reference Analog Board 2002 100 Bit...

Page 96: ...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 Bit pattern Register U400 01011101 U811 0000110...

Page 97: ...0V range Description The REFHI line is buffered by U255 to create REFBUF and tied to pin 1 of U420 and then buffered to form BUFF BUFF through R493 is tied to NET1 pin 1 R488 The divided voltage 100 a...

Page 98: ...1 gain Drawing reference Analog Board 2002 100 Components Q418 U410 U417 U419 U420 U423 and associated components Bit patterns Bit pattern Register U400 01110100 U811 00001101 U224 00010111 U432 10000...

Page 99: ...it Exercise Fault message None Description The SELFTEST control line turns ON Q425 and forces the voltage on NET1 R488 to ground The response of R488 pin 4 is stored in C439 This test uses the same pa...

Page 100: ...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 U400 01111101 U811 00001101 U224 00010111 U432 11111...

Page 101: ...s delay that controls U425 and Q414 is generated by U402 No measurement is made during this phase Drawing reference Analog Board 2002 100 Bit patterns Bit pattern Register U400 01111101 U811 00001101...

Page 102: ...422 U423 U425 U426 U433 and associated components Bit patterns Bit pattern Register U400 01111101 U811 00001101 U224 00010111 U432 00000000 U810 00000011 U206 10001110 U203 10001110 U411 00111011 U809...

Page 103: ...Type Circuit Exercise Fault message None Description The SELFTEST control line turns ON Q425 and forces the voltage on NET1 R488 to ground The response of R488 pin 4 is stored in C439 This test uses...

Page 104: ...03 10001110 U411 00111010 U809 11100111 U207 11001111 U221 11101001 U406 01101100 AD_STB MUX_STB R1_STB R2_STB Bits associated with register IC terminals as follows Q Q Q Q Q Q Q Q 87654321 87654321 8...

Page 105: ...delay that controls U425 and Q414 is generated by U402 No measurement is made during this phase Drawing reference Analog Board 2002 100 Bit patterns Bit pattern Register U400 01111101 U811 00001101 U2...

Page 106: ...U423 U425 U426 U420 and associated components Bit patterns Bit pattern Register U400 01111101 U811 00001101 U224 00010111 U432 00000000 U810 00000011 U206 01110000 U203 10001110 U411 00111010 U809 111...

Page 107: ...ed to pin 1 of U420 and buffered to form BUFF BUFF is routed through R493 K403 K401 input protection and Q421 is tied to the input buffer Q418 and U423 The buffered BUFF signal AMP IN is tied to the F...

Page 108: ...g reference Analog Board 2002 100 Components U410 U412 U417 U419 U420 U423 U426 and associated components Bit patterns Bit pattern Register U400 01011001 U811 00001101 U224 00010111 U432 11000000 U810...

Page 109: ...w turns Q421 ON and the signal is connected to buffer Q418 with output AMP IN AMP IN is monitored by the non inverting X1 gain path through Q412 to Q411 and U417 This section is only one half of the n...

Page 110: ...U203 10001110 U411 10111000 U809 00000000 U207 11001111 U221 11101001 U406 11101100 AD_STB MUX_STB R1_STB R2_STB Bits associated with register IC terminals as follows Q Q Q Q Q Q Q Q 87654321 87654321...

Page 111: ...patterns Bit pattern Register U400 01001100 U811 00001000 U224 00010111 U432 11001010 U810 00000000 U206 01110000 U203 10001110 U411 10111000 U809 00000000 U207 11001111 U221 11101001 U406 11101100 AD...

Page 112: ...nalog Board 2002 100 A D Converter 2002 160 Bit patterns Bit pattern Register U400 01001100 U811 00001000 U224 00010111 U432 11001010 U810 00000000 U206 01110000 U203 10001110 U411 10111000 U809 00000...

Page 113: ...100 A D Converter 2002 160 Bit patterns Bit pattern Register U400 01001100 U811 00001001 U224 00010111 U432 11001010 U810 00000000 U206 01110000 U203 10001110 U411 10111000 U809 00000000 U207 1100111...

Page 114: ...compared to the value obtained when the circuit was switched Drawing reference Analog Board 2002 100 A D Converter 2002 160 Bit patterns Bit pattern Register U400 01001100 U811 00000000 U224 00010111...

Page 115: ...essage 960 A ohms 2mA DCA range Description The 960 A ohms source is switched in using the OHMB control line at U223 and U220 U232 pin 2 to 3 connects the REFBUF to U233 pin 3 The 960 A current divide...

Page 116: ...plexer 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...

Page 117: ...100 Components U220 U222 U223 U225 U226 U232 U233 and associated components Bit patterns Test 500 5 Baseline reading for tests 500 6 and 500 7 Type Circuit Exercise Fault message None Description This...

Page 118: ...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 Bit pattern Register U400 011...

Page 119: ...generates 0 72mV at U225 pin 3 U225 is at unity gain so the same voltage is at DCA DCA is switched through U222 to the A D MUX U226 and the gain is X50 NOTE INPUT LO and AMPS must be externally jumper...

Page 120: ...ge at U225 pin 5 however the voltage is clamped at two diode drops approximately 1 2V by CR218 U225 is at unity gain so this voltage is at DCA DCA is switched through U222 to the A D MUX U226 and the...

Page 121: ...imately 1 2V by CR218 This voltage is fed to U225 pin 3 which is at unity gain so this voltage is at theAMPBOOT line AMPBOOT is switched through U222 to theA D MUX U226 and the gain is X1 NOTE INPUT H...

Page 122: ...buffer to the AMP IN line AMP IN is tied to the inverting and noninverting paths of the FWR NETOUT from U417 in the noninverting path is monitored by the ZERO CROSSING amp for either polarity of input...

Page 123: ...TS 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 Bit patterns Bit pattern R...

Page 124: ...SE jacks must be externally shorted together to run this test Drawing reference Analog Board 2002 100 Components R360 U242 and associated components Bit patterns Bit pattern Register U400 01111011 U81...

Page 125: ...Troubleshooting 2 112...

Page 126: ...fan from the chassis 3 8 Firmware replacement Provides the procedure to change firmware 3 9 Instrument re assembly Provides some general guidelines to follow when re assembling the Model 2002 3 10 Ass...

Page 127: ...es as required The first procedure removes the case cover and the second pro cedure removes the top shield of the analog board allowing access to analog circuitry 3 4 1 Case cover removal WARNING Befo...

Page 128: ...oard in front of the bank of 12 capacitors Another screw is located next to the 5V regulator U629 The other two screws are located near the connector for the option slot 3 Remove Digital Board The boa...

Page 129: ...ext to the INPUTS switch Terminal wire color identification for re assembly is as fol lows Terminal Front Rear INPUT HI Red White Red INPUT LO Black White Black SENSE HI Yellow White Yellow SENSE LO G...

Page 130: ...igital board in front of the IEEE 488 connector Re turn the chassis to the right side up position 2 Remove Mounting Nuts The fan is secured to the chassis by two mounting nuts Remove these nuts and pu...

Page 131: ...ceptacle and the power transform er ground are connected to the chassis 3 10 Assembly drawings The following assembly drawings are provided to assist in disassembly and re assembly of the instrument A...

Page 132: ...odel number Model 2002 Instrument serial number Part description Component designation if applicable Keithley part number To facilitate repairs complete circuit boards are available Contact the Repair...

Page 133: ...25MW METAL FILM RES 1 28M 1 1 8W METAL FILM RES 150 5 125MW METAL FILM RES 200K 5 125MW METAL FILM RES 2K 5 125MW METAL FILM RES 470 5 125MW METAL FILM RES 5 1K 5 125MW METAL FILM RES 49 9K 1 125MW ME...

Page 134: ...BAV103 DIODE SWITCHING MMBD914 VACUUM FLUORESCENT DISPLAY CABLE ASSEMBLY TRANS NPN GEN PURPOSE BC868 RES NET 15K 2 1 875W RES 13K 5 125MW METAL FILM RES 4 7K 5 250MW METAL FILM RES 1M 5 125MW METAL F...

Page 135: ...M ELEC CAP 470UF 20 63V ALUM ELEC CAP 1000UF 20 35V ALUM ELEC CAP 100UF 20 10V ALUM ELEC CAP 022UF 10 50V CERAMIC CAP 20PF 5 500V DIPPED MICA CAP 01UF 20 50V CERAMIC CAP 68UF 20 50V POLYESTER FILM CAP...

Page 136: ...T400 LED PL 92 1 E201 E295 SURGE ARRESTOR SELECTED CG 3 1 52 RES NET 900 90 9 10 SA 5 TF 168 1 F101 F201 FUSE 5A 250V FUSE 2A 250V FAST BLO 5X20MM FU 71 FU 48 J1002 J1022 1023 J1024 1025 J1026 CONN M...

Page 137: ...261 TG 239 TG 198 TG 158 TG 196 1 31841A TG 274 TG 278 2002 600A 182 600B 2001 601A TG 276 TG 287 TG 218 TG 166 1 TG 241 TG 247 TG 250 TG 219 TG 235 TG 176 TG 257 TG 243 TG 243 R101 R102 103 128 R104...

Page 138: ...3K 5 125MW METAL FILM RES NET 13 1K 13 3K 0 1 100MW THINFILM RES 120 1 25W PRECISION WIREWOUND RES 1K 1 3W 300V METAL FOIL RES 7 5K 1 3W 300V METAL FILM RES 75K 1 3W 300V METAL FOIL RES 1K 1 125MW MET...

Page 139: ...METAL FILM RES 620 5 250MW METAL FILM RES 68 5 125MW METAL FILM RES 2 15K 1 125MW METAL FILM RES 1K 5 125MW METAL FILM RES 7 5K 5 125MW METAL FILM RES 68K 5 125MW METAL FILM RES NET 250K 9 34K 1K 10...

Page 140: ...LTC1043CS IC ULTRA PRECISION REF LT21000A PKG H8 IC CMOS ANAL SWITCH DG411DY IC 8 CHAN ANA MULTIPLEXER DG408DY IC CENTRIGRADE TEMP SENSOR LN35DM IC 22V OP AMP LT1007ACN8 IC CMOS ANAL SWITCH DG444DY I...

Page 141: ...DIODE ZENER 6 2V BZX84B6V2 DIODE ZENER 39V MLL4716 DIODE ZENER 5 1V BZX84C5V1 DIODE ZENER 4 3V BZX84C4V3 DIODE ZENER 8 2V MMBZ5237 DIODE ZENER 22V BZV55C22 VAR 576V METAL OXIDE DIODE ZENER 10V MMSZ52...

Page 142: ...J1028 J1029 1030 J1031 J1032 J1033 J1034 CONN HEADER STRAIGHT SOLDER PIN CONN RIGHT ANGLE 24PIN CONN MICRODIN W GND FINGERS CONN RT ANGLE MALE 9 PIN CONN RT ANGLE MALE MOLEX 156 CONN HEADER STRAIGHT...

Page 143: ...D SINL DRIVER UDN 2596A IC OCT BFR LINE DRIVE 74HCT244 IC QUAD 2 IN NOR 74HCT02 IC QUAD 2 INPUT OR 74HCT32 PROGRAMMED EPROM EPM5064LC PLCC IC 5V VOLTAGE REGULATOR LM2940CT IC DUAL POWER SUPPLY SUPER T...

Page 144: ...0MM HANDLE LEXAN ANALOG BOTTOM SHIELD LEXAN SHIELD CHASSIS RIGHT MOUNTING EAR LEFT MOUNTING EAR RIGHT POWER ROD PRINTED FRONT PANEL SHIELD SHIELDED ANALOG BOTTOM SHIELD SHIELDED ANALOG TOP SHIELD TRAN...

Page 145: ...A Specifications A 1...

Page 146: ...l 3 2 Case cover removal 3 2 Character set test 2 3 Component layouts 4 1 Control register bit patterns 2 3 Control register ICs 2 3 Cooling fan removal 3 5 Current fuse replacement 1 2 D Diagnostics...

Page 147: ...r supply circuit theory 2 11 Principles of operation 2 6 R Rear AMPS input fuse 1 3 Regulator and switching tests 2 70 Repair considerations 2 2 Replaceable parts 4 1 Routine maintenance 1 1 S Sample...

Page 148: ...nstable Will not read applied input Overload Calibration only Certi cate of calibration required Data required attach any additional sheets as necessary Show a block diagram of your measurement system...

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