Keithley 2001 Repair Manual

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Model 2001

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Repair Manual

Contains Servicing Information

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Troubleshooting

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Page 1 Model 2001 Multimeter Repair Manual Contains Servicing Information...
Page 2 Keithley Instruments, Inc. • 28775 Aurora Road • Cleveland, OH 44139 • 216-248-0400 • Fax: 216-248-6168 • http://www.keithley.com CHINA: Keithley Instruments China • Yuan Chen Xin Building, Room 705 • No. 12 Yumin Road, Dewei, Madian • Beijing, China 100029 • 8610-2022886 • Fax: 8610-2022892 FRANCE: Keithley Instruments SARL •...
Page 3 Model 2001 Multimeter Repair Manual ©1993, Keithley Instruments, Inc. Test Instrumentation Group All rights reserved. Cleveland, Ohio, U.S.A. Second Printing, February 1996 Document Number: 2001-902-01 Rev. B...
Page 4 Revision A (Document Number 2001-902-01).................. April 1993 Revision B (Document Number 2001-902-01)................February 1996 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 Safety Precautions The following safety precautions should be observed before Do not exceed the maximum signal levels of the instruments using this product and any associated instrumentation. Al- and accessories, as deÞned in the speciÞcations and operat- though some instruments and accessories would normally be ing information, and as shown on the instrument or test Þx- used with non-hazardous voltages, there are situations ture rear panel, or switching card.
Page 6: 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..........................1-2 Fan filter cleaning ............................. 1-3 Firmware updates .............................. 1-3 Troubleshooting Introduction ...............................
Page 7 3.2.2 Solder repairs............................3-2 Special handling of static sensitive devices...................... 3-2 Case cover and shield removal ......................... 3-2 3.4.1 Case cover removal ..........................3-2 3.4.2 Analog board top shield removal ......................3-3 PC-boards removal ............................3-3 3.5.1 Digital board............................3-3 3.5.2 A/D converter board..........................
Page 8 List of Illustrations Routine Maintenance Figure 1-1 Line fuse location ..........................1-1 Figure 1-2 Front AMPS input fuse location ......................1-2 Figure 1-3 Rear AMPS input fuse location ......................1-3 Troubleshooting Figure 2-1 Model 2001 overall block diagram..................... 2-16...
Page 9 R2_STB control registers ........................2-21 Table 2-13 Multiplexer (U511)..........................2-22 Replaceable Parts Table 4-1 Model 2001 A/D board, parts list ......................4-2 Table 4-2 Model 2001 analog board, parts list ..................... 4-5 Table 4-3 Model 2001 digital board, parts list....................4-15 Table 4-4 Model 2001 display board, parts list....................
Page 10: Routine Maintenance
Routine Maintenance Introduction 1. Insert a bladed screwdriver into the slot of the fuse carrier. In general, the information in this section deals with 2. While pushing in, turn the screwdriver counter- routine type maintenance that can be performed by the clockwise until the spring loaded fuse carrier re- operator.
Page 11: Current Fuse Replacement
SENSE INPUT Ω 4 WIRE MATH AUTO ARM TRIG SMPL Keithley 350V 1100V Size Rating Part No. PEAK PEAK 2001 MULTIMETER 5 × 20mm 250V, A, Slo-Blo FU-71 500V PEAK INPUTS RANGE AUTO FRONT/REAR 2A 250V AMPS RANGE Current fuse replacement...
Page 12: Fan Filter Cleaning
It is possible that you may receive a Þrmware update The Þlter for the cooling fan requires periodic cleaning from Keithley to enhance operation and/or Þx ÒbugsÓ. to maintain proper ventilation. The fan Þlter is accessi- The Þrmware program for the main microprocessor is ble from the rear panel.
Page 13 Routine Maintenance service personnel. The procedure to replace the Þrm- ware (U611) is contained in paragraph 3.8.
Page 14: Troubleshooting
Front panel tests Ñ Provides the procedures to Repair considerations test the functionality of the front panel keys and the display. Before making any repairs to the Model 2001, be sure to read the following considerations.
Page 15: Power-On Test
3.3. 2.4.2 DISPLAY PATTERNS Test 5. Anytime a circuit board is removed or a compo- nent is replaced, the Model 2001 will have to be The display test allows you to verify that each pixel recalibrated.
Page 16: Built-In Test
Troubleshooting Table 2-1 FRONT PANEL TESTS Built-in-test summary KEYS DISPLAY-PATTERNS 4. Place the cursor on DISPLAY-PATTERNS and Test Circuit tested/exercised press ENTER to start the display test. There are Þve 100 Series Memory: parts to the display test. Each time a front panel 100.1 EPROM key (except EXIT) is pressed, the next part of the...
Page 17 Troubleshooting Table 2-1 (cont.) Table 2-1 (cont.) Built-in-test summary Built-in-test summary Test Circuit tested/exercised Test Circuit tested/exercised 302 Series Ohms: 308 Series 4-Digit Mode: 302.1 Zero Reference Measure- 308.1 A/D MUX 4-Digit Signal ment (for next test) Path 302.2 Open Circuit Ohms and 308.2 A/D MUX 4-Digit Zero Ohms Protection...
Page 18 Troubleshooting Table 2-1 (cont.) Table 2-1 (cont.) Built-in-test summary Built-in-test summary Test Circuit tested/exercised Test Circuit tested/exercised 405 Series Absolute Value (x10 Gain): 409 Series /750 Correction Factor: 405.1 Gain Comparison (Large 409.1 Circuit Setup (for next test) +DAC Output) 409.2 Signal Stored (for next test) 405.2...
Page 19: 1Automatic Testing2-6
Troubleshooting 5. After repairing the instrument, start again at step 1 The star (*) is only displayed if a failure occurs. to check the integrity of the repair and to see if there are any other failures. 7. If all the tests passed (no star displayed), use the EXIT key to back out of the menu structure.
Page 20: Diagnostics
Diagnostics pressed, any test in process will be allowed to Þnish before aborting the testing process. The Model 2001 has diagnostic test modes which allow B. CONTINUOUS looping continuously repeats you to ÒfreezeÓ instrument operation to allow you to all the tests in the speciÞed series until the test- check logic levels on the DC_STB control registers ing process is manually stopped.
Page 21 Troubleshooting test modes and the key scrolls backward. of the menu structure and return to the normal Again, use the appropriate tables to determine the measurement mode of operation. bit pattern at the control registers. 8. If you wish to check another function/range, re- 7.
Page 22 Troubleshooting Table 2-3 Table 2-4 DIAGNOSTICS test modes ( Ω 4 function; 20 Ω DIAGNOSTICS test modes ( Ω 4 function; 2k Ω and 200 Ω ranges) thru 200k Ω ranges) Test mode Bit pattern Test mode Bit pattern designator* designator* Ohms sense high Ohms sense high...
Page 23 Table 2-5 DIAGNOSTICS bit patterns (DC_STB registers) Registers U303 U300 U800 U801 pattern Q8 Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q8 Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q8 Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q8 Q7 Q6 Q5 Q4 Q3 Q2 Q1...
Page 24: R1_Stb And R2_Stb Shift Registers
Troubleshooting R1_STB and R2_STB shift registers To use these tables, simply place the instrument in the designated function and range and check the output of Table 2-6 and Table 2-7 are provided to allow you to the shift registers for the indicated bit pattern. The bit check logic levels on the R1_STB and R2_STB shift reg- patterns in these tables assume the following condi- isters (U302, U305, U307, U501, U530, U500 and U505)
Page 25 Table 2-6 Bit patterns for R1_STB registers Function Range Registers U302 U305 U307 Q8 Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q8 Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q8 Q7 Q6 Q5 Q4 Q3 Q2 Q1 200mV-20V 200V, 1000V 200µA 20mA 200mA...
Page 26 Troubleshooting Table 2-7 Bit patterns for R2_STB registers Registers U501 U530 Function Range Q8 Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q8 Q7 Q6 Q5 Q4 Q3 Q2 Q1 200mV 200V 750V Ω2, Ω4 Registers U500 U505 Range Range Q8 Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q8 Q7 Q6 Q5 Q4 Q3 Q2 Q1 200mV 200V...
Page 27: Display Board Checks
Troubleshooting Display board checks Power supply checks If the FRONT PANEL TESTS (paragraph 2.4) indicate Power supply problems can be checked out using Ta- that there is a problem on the display board, use Table ble 2-9. 2-8. Circuit theory for the display is provided in paragraph 2.9.1.
Page 28: Documentation
2.10.1 and 2.10.2. ered in this section of the manual. Figure 2-1 provides an overall block diagram of the Model 2001 showing the major circuit groups. Most circuits in the Model 2001 are tested and/or exercised by Built-in Test. A...
Page 29 Troubleshooting Figure 2-1 Model 2001 overall block diagram 2-16...
Page 30: Display Board Circuit Theory
Troubleshooting 2.10.1 Display board circuit theory 2.10.2 Power supply circuit theory The following information provides some basic circuit The following information provides some basic circuit theory that can be used as an aide to troubleshoot the theory that can be used as an aide to troubleshoot the display and keyboard.
Page 31: Built-In Test Documentation
Troubleshooting Line voltage (110V/220V) selection circuit If the power line voltage decreases to a low level, U105 will turn off, but the output of U110 will remain latched This circuit automatically selects the proper power line at +8V. However, the LOW line will be driven low turn- voltage setting for the instrument.
Page 32: Table
Troubleshooting Table 2-10 DC_STB control registers Register Control Description U801 FAST 1 = FAST integration on A/D converter (ADC). LST_PH 1 = Normal ADC operation. FREQ_EN 1 = Normal ADC operation. I3, FREQ_LOAD 1 = Normal ADC operation. Set ADC conversion rate (LSB). Set ADC conversion rate.
Page 33: Table
Troubleshooting Table 2-11 R1_STB control registers Register Control Description U307 OHM FA U332 ohms range select (LSB). OHM FB U332 ohms range select (MSB). 4W OHM 0 = U323 closed, 1 = U323 open. /OHM CAL 0 = OHM CAL to A/D Buffer (via U320). /4 DIGIT 0 = BSCOM or common (via U317) to A/D Buffer (U319 closed).
Page 34: Troubleshooting
Troubleshooting Table 2-12 R2_STB control registers Register Control Description U505 0 = U526 (divider) closed and U526 (ACA) open. SELFTEST 1 = Q518 off, U513 arms U503, and U522 (control pin 9) open. SELFTESTEN 1 = Arms U513 (pin 5) for SELFTEST. SHORT 0 = U526 closed (common to AC Buffer).
Page 35: Table 2-13 Multiplexer (U511)
Troubleshooting Table 2-13 Multiplexer (U511) MUX Control Lines SEL3 SEL2 SEL1 Selected Input IN1; Peak output IN2; Filter output IN3; TRMS output IN4; ACF output IN5; RectiÞer output IN6; SELFTEST OUT IN7; AMP IN output IN8; Common 2-22...
Page 36 Troubleshooting Memory element tests Tests 100.1, 101.1 and 102.1 check the memory elements (ROM, RAM and E PROM) of the Model 2001. Test 100.1 – EPROM Type Pass/Fail Failure analysis Cannot properly read ROM. Description All ROM bytes (except checksum bytes) are read, a checksum is calculated and com- pared to the stored checksum.
Page 37 Troubleshooting Digital I/O tests The Digital I/O on the Model 2001 consists of four open collector outputs, and one TTL-level input. Outputs originate from Port A of the 68302 microprocessor (U626), lines PA4 through PA7. PA4 drives Output #1, PA5 drives Output #2, PA6 drives Out- put #3 and PA7 drives Output #4.
Page 38 IEEE-488 bus tests The IEEE-488 interface in the model 2001 consists of the 9914 GPIB 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 cir- cuitry to test these components is contained in the 5064 ASIC (U618).
Page 39 System trigger inputs are normally pulled up to 5V through the protection diodes and 5.1k Ω resistors (CR611-CR616, R648-R650 and R655-R657). The Model 2001 can gener- ate a trigger on any of the six trigger bus inputs by turning on the appropriate FET (Q602-Q607).
Page 40 Troubleshooting Test 105.8 – Group Execute Trigger (GET) Type Pass/Fail Failure analysis GET signal not detected. Description Trigger 8 (STI8) is set up as an input and the 9914 (U622) is then programmed to gen- erate a GET signal. High suspect U618 and U622.
Page 41 Troubleshooting Test 200.1 – A/D zero Type Pass/Fail Failure analysis No A/D communication and/or noisy A/D. Description This test turns on Q328 by setting /HIV low and turns on Q525 by setting /DIVIDER low. Switches U319 (/ZERO pulled low) and U318 (/X1 pulled low) are closed and U808 is set for line cycle integration.
Page 42 Troubleshooting Test 200.2 – A/D noise Type Pass/Fail Failure analysis Noisy signal conditioning. Description This test uses the same circuit setup as test 200.1. The A/D is triggered for 10 readings and a mininmum/maximum comparison is done for 30 counts or less. Failing this test indicates A/D buffer noise or A/D converter circuit noise.
Page 43 Troubleshooting Test 200.3 – FAST circuit Type Pass/Fail Failure analysis Defective FAST circuit Description This test uses the same circuit setup as Test 200.1. Line cycle integration and FAST is selected on U808. The FAST circuit includes U806 (FS1), Q813, R842, and the FS1 con- trol line from U808.
Page 44 Troubleshooting Test 200.4 – x10 line cycle integration Type Pass/Fail Failure analysis Cannot select x10 line cycle integration. Description Same circuit setup as test 200.1 but x10 line cycle integration selected. ConÞgures I3 through I13 for x10 line integration. High suspect U801, U800, and U808.
Page 45 Troubleshooting Test 200.5 – x0.1 line cycle integration Type Pass/Fail Failure analysis Cannot select x0.1 line cycle integration. Description Same circuit setup as test 200.1 but x0.1 line cycle integration selected. ConÞgures I3 through I13 for x0.1 line integration. High suspect U801, U800, and U808.
Page 46 Troubleshooting Test 200.6 – x0.02 line cycle integration Type Pass/Fail Failure analysis Cannot select x0.02 line cycle integration. Description Same circuit setup as test 200.1 but x0.02 line cycle integration selected. ConÞgures I3 through I13 for x0.02 line integration. High suspect U801, U800, and U808.
Page 47 Troubleshooting Test 200.7 – x0.01 line cycle integration Type Pass/Fail Failure analysis Cannot select x0.01 line cycle integration. Description Same circuit setup as test 200.1 but x0.01 line cycle integration selected. ConÞgures I3 through I13 for x0.01 line integration. High suspect U801, U800, U808, and FAST circuitry (see test 200.3).
Page 48 Troubleshooting Test 201.1 – Test cal zero Type Circuit exercise Description Same circuit setup as test 200.1. A zero reading is acquired for tests 201.2 and 201.3. Bit pattern DC_STB R1_STB R2_STB Registers Registers Registers U801 U307 U505 U800 U305 U500 U300 U302...
Page 49 Troubleshooting Test 201.2 – 7V reference Type Pass/Fail Failure analysis Cannot measure 7V at A/D IN. Description This test turns on Q328 by setting /HIV low and turns on Q525 by setting /DIVIDER low. Switches U317 (/REF pulled low) and U318 (/X1 pulled low) are closed and U808 is set for line cycle integration.
Page 50 Troubleshooting Test 201.3 – 1.75V reference Type Pass/Fail Failure analysis Cannot measure 1.75V at A/D IN. Description This test turns on Q328 by setting /HIV low and turns on Q525 by setting /DIVIDER low. Two switches of U318 (/2VREF pulled low) and (/X1 pulled low) are closed and U808 is set to line cycle integration.
Page 51 Troubleshooting Test 300.1 – A/D mux, A/D buffer, 7V reference, x1.5 gain Type Pass/Fail Failure analysis Cannot measure 10.5V ±1.5V at A/D IN. Description This test switches the 7V reference (REF OUT from U329, pin 1) through analog switch U317 (/REF pulled low) to the non-inverting input of Op Amp U322. Analog switch U319 (//2 pulled low) is closed and Q306 is turned on (BUF = 0V) connecting R327 to common.
Page 52 Troubleshooting Test 300.2 – A/D mux, A/D buffer, 1.75V reference, x5 gain Type Pass/Fail Failure analysis Cannot measure 8.75V ±0.875 at A/D IN. Description This test switches the 1.75V reference (U327 output) through analog switch U318 (/2VREF pulled low) to the non-inverting input of Op Amp U322. Analog switch U318 (/X5 pulled low) is closed to use resistors R326 and R335 to obtain a gain of x5.
Page 53 Troubleshooting Test 300.3 – A/D mux, A/D buffer, 0V reference, x5 gain Type Pass/Fail Failure analysis Cannot measure 0V ±0.01V at A/D IN. Description This test switches common through R340 and analog switch U319 (/ZERO pulled low) to the non-inverting input of Op Amp U322. Analog switch U318 (/X50 pulled low) is closed to use thick Þlm resistor R215 to obtain a gain of x50.
Page 54 Troubleshooting Test 301.1 – Input buffer, front end (FE) zero Type Pass/Fail Failure analysis Cannot measure 0V ±0.02V at A/D IN. Description The front end (FE) zero (common) is switched through U323 (4W OHM pulled low) and Q527 (FE ZERO = 0V) to Q330. Pin 6 of Q330 and pin 6 of input buffer U335 should be at 0V.
Page 55 Troubleshooting Test 301.2 – Input buffer, divided by 100 Type Pass/Fail Failure analysis Cannot measure 0V ±0.01V at A/D IN. Description This test routes 0V (common) to input buffer U335. The 0V signal path to the input buff- er is through FET Q328 (/HIV pulled low), the 100kΩ leg of R394, FET Q525 (/DIVID- ER = 0V) and Þnally through signal FETs Q522 and Q523 (VLO2 is ßoating and pin 4 of U339 is at 0V) to pin 2 of Q330.
Page 56 Troubleshooting Test 302.1 – Ohms; zero reference measurement for test 302.2 Type Circuit Exercise Description This measurement is the same as the one in test 301.1. Although the reading is very close to 0V, it is not exactly zero due to offsets in the input buffer and A/D buffer cir- cuits.
Page 57 Troubleshooting Test 302.2 – Ohms; open circuit and protection Type Pass/Fail Failure analysis Cannot measure 5.9V ±0.59V at A/D IN. Description This test closes the ohms circuit feedback loop by selecting the 9.2mA ohms source re- sistor path (parallel combination of R355, R356 and R357). The parallel resistor combi- nation is conÞgured by closing the switches at pins 1 and 12 of U332.
Page 58 Troubleshooting Test 303.1 – Input path; zero reference measurement for test 303.2 Type Circuit Exercise Description This measurement is exactly the same as test 301.1. Although the reading is very close to 0V, it is not exactly zero due to offsets in the input buffer and A/D buffer circuits. This reading is used as the zero reference for test 303.2.
Page 59 Troubleshooting Test 303.2 – Input path; open circuit ohms and ohms protection Type Pass/Fail Failure analysis Cannot measure 5.9V ±0.59V. Description This test uses the same open circuit ohms voltage as test 302.2, except the voltage is routed through the input path of Q340, Q339, Q338, Q337, and Q333 (/LOV/OHM = 5.9V)) to the input buffer.
Page 60 Troubleshooting Test 303.3 – Input path; front end (FE) zero protection Type Pass/Fail Failure analysis Cannot measure 2.5V ±2.5V at A/D IN. Description This test is identical to test 303.2, except that Q539 (FE ZERO = 0V) is turned on. Some current will ßow through Q340, Q339, Q338, and Q337.
Page 61 Troubleshooting Test 304.1 – Ohms sources; zero reference measurement for tests 304.2 – 304.7 Type Circuit Exercise Description This measurement is exactly the same as test 301.1. Although the reading is very close to 0V, it is not exactly zero due to offsets in the input buffer and A/D buffer circuits. This reading is used as the zero reference for tests 304.2 through 304.7.
Page 62 Troubleshooting Test 304.2 – Ohms sources; 0.98mA and 9.2mA Type Pass/Fail Failure analysis Cannot measure 0.78V ±0.08V at A/D IN. Description Switches in R358 for the 0.98mA ohms source by closing the analog switches at pins 5 and 14 of U332. The parallel combination of R355, R356 and R357 (used for the 9.2mA source during normal operation) acts as the load and is connected to common through the analog switch at pin 1 of U325.
Page 63 Troubleshooting Test 304.3 – Ohms sources; 89µA and 0.98mA Type Pass/Fail Failure analysis Cannot measure 0.65V ±0.065V at A/D IN. Description Switches in R365 for the 89uA ohms source by closing the analog switches at pins 2 and 15 of U332. R358 (used for the 0.98mA ohms source during normal operation) acts as the load and is connected to common through the analog switch at pin 5 of U325.
Page 64 Troubleshooting Test 304.4 – Ohms sources; 7µA and 89µA Type Pass/Fail Failure analysis Cannot measure 0.56V ±0.056V at A/D IN. Description Switches in R366 for the 7uA ohms source by closing the analog switches at pins 4 and 11 of U332. R365 (used for the 89uA ohms source during normal operation) acts as the load and is connected to common through the analog switch at pin 2 of U325.
Page 65 Troubleshooting Test 304.5 – Ohms sources; 770nA and 7µA Type Pass/Fail Failure analysis Cannot measure 0.7V ±0.07V at A/D IN. Description Switches in R366 for the 7µA ohms source as in test 304.4. R394 (used for the 770nA ohms source during normal operation) acts as the load and is connected to common by turning on Q328 (/HIV pulled low).
Page 66 Troubleshooting Test 304.6 – Ohms sources; 70nA and 770nA Type Pass/Fail Failure analysis Cannot measure 0.7V ±0.07V at A/D IN. Description Switches in R354 for the 70nA ohms source by closing the analog switches at pins 1 and 12 of U332. Q324 (HI OHM pulled low) is on while Q312 and Q320 are off. This selects R354 as the only source resistor.
Page 67 Troubleshooting Test 304.7 – Ohms sources; 4.4nA and 770nA Type Pass/Fail Failure analysis Cannot measure 2.2V ±0.6V at A/D IN. Description This test uses the same ohms source resistor (R354) as the previous test except that an- alog switch U323 (/200M pulled low) is closed to conÞgure Op Amp U324 into a divide by 16 ampliÞer.
Page 68 Troubleshooting Test 305.1 – Input divider; zero reference measurement for test 305.2 Type Circuit Exercise Description This measurement is exactly the same as test 301.1. Although the reading is very close to 0V, it is not exactly zero due to offsets in the input buffer and A/D buffer circuits. This reading is used as the zero reference for test 305.2.
Page 69 Troubleshooting Test 305.2 – Input divider; divide by 100 Type Pass/Fail Failure analysis Cannot measure 2.95V ±0.295V at A/D IN. Description Basically, this test utilizes the same open circuit ohms scheme as test 302.2. The 9.2mA ohms source is connected through R394 (10M Ω ) to common via Q328. The open circuit ohms circuit clamps the voltage drop across R394 to approximately 5.9V.
Page 70 Troubleshooting Test 306.1 – Ohms cal switch Type Pass/Fail Failure analysis Cannot measure 0V ±0.001V at A/D IN. Description On U325, OHM CAL is connected to common by closing the analog switches at pins 1 and 12. Analog switch U320 (/OHM CAL pulled low) routes this 0V signal to the A/ D buffer.
Page 71 Troubleshooting Test 307.1 – Cal divider; zero reference for test 307.2 Type Circuit Exercise Description This measurement is exactly the same as test 301.1. Although the reading is very close to 0V, it is not exactly zero due to offsets in the input buffer and A/D buffer circuits. This reading is used as the zero reference for test 307.2.
Page 72 Troubleshooting Test 307.2 – Cal divider; A/D mux/10 Type Pass/Fail Failure analysis Cannot measure 3.8V ±0.38V at A/D IN. Description Uses the 0.98mA ohms source and parallel combination of R355, R356 and R357 as a load (same as test 304.2). The 0.78V output of the input buffer is divided by 10 (R342 and R343) and routed through U319 (/CAL pulled low) to the A/D buffer.
Page 73 Troubleshooting Test 307.3 – Cal divider; A/D mux/buffer (x-0.5) Type Pass/Fail Failure analysis Cannot measure -2.9V ±0.4V at A/D IN. Description Uses the 9.2mA ohms source basically the same way as test 305.2. A no load condition causes the 5.9V open circuit ohms circuit to be operational. This voltage is routed through the 9.9M Ω...
Page 74 Troubleshooting Test 308.1 – 4-digit mode; A/D MUX signal path Type Pass/Fail Failure analysis Cannot measure 0.78V ±0.078V at A/D IN. Description The ohms source is conÞgured the same as in tests 304.2 and 307.2. The output of U335 is 0.78V, which is the same as bootstrap common (BSCOM). In 4-digit mode, BSCOM is routed through U319 (/4 DIGIT pulled low) to the non-inverting input of Op Amp U322, which is conÞgured for x1 gain.
Page 75 Troubleshooting Test 308.2 – 4-digit mode; A/D MUX zero path Type Pass/Fail Failure analysis Cannot measure 0V ±0.01V at A/D IN. Description Common for the 4-digit mode is routed through U317 (4 DIGIT pulled low) and U319 (/4 DIGIT pulled low) to the non-inverting input of Op Amp U322, which is conÞgured for x1 gain.
Page 76 Troubleshooting Test 309.1 – Amps; 200µA range Type Pass/Fail Failure analysis Cannot measure 0.089V ±0.0089V at A/D IN. Description The 89µA ohms source is switched through U323 (/ACAL pulled low) and the 200uA range switch U317 (/200µA pulled low). Current ßows through thick Þlm R344 (all three resistors), R592 and R591 to common.
Page 77 Troubleshooting Test 309.2 – Amps; 2mA range Type Pass/Fail Failure analysis Cannot measure 0.098V ±0.0098V at A/D IN. Description The 0.98A ohms source is switched through U323 (/ACAL pulled low), U317 (/2mA pulled low), the 90 Ω and 9 Ω legs of R344, R592 and R591 to common. Op Amp U322 is conÞgured for x1 gain.
Page 78 Troubleshooting Test 309.3 – Amps; 20mA range Type Pass/Fail Failure analysis Cannot measure 0.092V ±0.0092V at A/D IN. Description The 9.2mA ohms source is switched through U323 (/ACAL pulled low), Q311, the 9Ω leg of R344, R592 and R591 to common. Op Amp U322 is conÞgured for x1 gain. Mea- sure 92mV (9.2mA ×...
Page 79 Troubleshooting Test 309.4 – Amps; reference measurement for tests 309.5 and 309.6 Type Circuit Exercise Description The 9.2mA ohms source is applied through U323 (/ACAL pulled low) directly to the amps protection diodes CR305 and CR309. None of the amps switches or FETS are closed.
Page 80 Troubleshooting Test 309.5 – Amps; 200mA range Type Pass/Fail Failure analysis Cannot measure (0.475V + Test 309.4) ±0.0475V at A/D. Description The 9.2mA ohms source is switched through U323 (/ACAL pulled low), Q309 and Q307 (/200mA = +15v), R592 and R591 to common. Op Amp U322 is conÞgured for x50 gain.
Page 81 Troubleshooting Test 309.6 – Amps; 2A range Type Pass/Fail Failure analysis Cannot measure (0.0462V + Test 309.4) ±0.00462V at A/D IN. Description The 9.2mA ohms source is switched through U323 (/ACAL pulled low), Q310 and Q305 (/2A = +15v) and R591 to common. Op Amp U322 is conÞgured for x50 gain. Measure approximately 46mV at A/D IN (9.2mA x 0.1Ω...
Page 82 Troubleshooting Test 310.1 – Amps protection Type Pass/Fail Failure analysis Cannot measure 1.7V ±0.3V at A/D IN. Description The 9.2mA ohms source is set up to source current on the 200µA range as in test 309.1. The load resistance for the 200µA range is 1000.01Ω. Diodes CR305 and CR309 clamp the amps circuit voltage to three diode drops.
Page 83 Troubleshooting Test 400.1 – DAC; -4.21V output Type Pass/Fail Failure analysis DAC output not -4.21V ±0.4V. Description The TRIG bits for OUT B of the DAC (U531) are programmed to produce -4.21V at PRE- COM+ (pin 1 of U528). This signal is routed through R560 and U532 (DAC line pulled low).
Page 84 Troubleshooting Test 400.2 – DAC; -2.08V output Type Pass/Fail Failure analysis DAC output not -2.08V ±0.34V. Description Same as test 400.1 except OUT B of the DAC is conÞgured for -2.08V. Measure -2.08V at A/D IN. Bit pattern DC_STB R1_STB R2_STB Registers Registers...
Page 85 Troubleshooting Test 400.3 – DAC; 0V output Type Pass/Fail Failure analysis DAC output not 0.001V ±0.28V. Description Same as test 400.1 except OUT B of the DAC is conÞgured for 0V. Measure 0V at A/D Bit pattern DC_STB R1_STB R2_STB Registers Registers Registers...
Page 86 Troubleshooting Test 400.4 – DAC; 2.25V output Type Pass/Fail Failure analysis DAC output not 2.25V ±0.34V. Description Same as test 400.1 except OUT B of the DAC is conÞgured for 2.25V. Measure 2.25V at A/D IN. Bit pattern DC_STB R1_STB R2_STB Registers Registers...
Page 87 Troubleshooting Test 400.5 – DAC; 4.33V output Type Pass/Fail Failure analysis DAC output not 4.33V ±0.4V. Description Same as test 400.1 except OUT B of the DAC is conÞgured for 4.33V. Measure 4.33V at A/D IN. Bit pattern DC_STB R1_STB R2_STB Registers Registers...
Page 88 Troubleshooting Test 401.1 – Signal switching; zero cal switch Type Pass/Fail Failure analysis Cannot measure 0V ±0.001V at A/D IN. Description Common is routed to the ACF line through U526 (SHORT pulled low). ACF is then routed through multiplexer U511. The output of the multiplexer (OUT) follows the same path to the A/D buffer (U322) as the 400 series tests.
Page 89 Troubleshooting Test 402.1 – Signal switching; frequency switch Type Pass/Fail Failure analysis Cannot measure 0.032V ±0.005V at A/D IN. Description OUT B of the DAC (U531) is set up to output 4.33V at PRECOMP+ (U528 pin 1). The operation of the frequency switch, U522 (FREQ pulled low), is veriÞed by dividing the PRECOMP+ voltage by the voltage ratio across R560 and R558.
Page 90 Troubleshooting Test 403.1 – Signal switching; ground switch Type Pass/Fail Failure analysis Cannot measure 0.001V ±0.005V at A/D IN. Description Common at pin 9 of U511 is multiplexed to pin 8 (OUT) and measured in the same manner as the previous 400 series tests. Measure 0V at A/D IN. Bit pattern DC_STB R1_STB...
Page 91 Troubleshooting Test 404.1 – Absolute value (x1 gain); -full-scale DAC output Type Pass/Fail Failure analysis Cannot measure 4.21V ±0.4V at A/D IN. Description DAC U531 is programmed to generate -4.21 VDC at PRECOMP+. That signal is then applied to ACF through R560 and U532 (DAC line pulled low). ACF is routed to AMP IN via U526, Q516, and the AC input buffer.
Page 92 Troubleshooting Test 404.2 – Absolute value (x1 gain); -half scale DAC output Type Pass/Fail Failure analysis Cannot measure 2.08V ±0.34V at A/D IN. Description ADC U531 is programmed to generate -2.08 VDC at PRECOMP+. This signal follows the same path as test 404.1. Measure +2.08V at A/D IN. Bit pattern DC_STB R1_STB...
Page 93 Troubleshooting Test 404.3 – Absolute value (x1 gain); zero DAC output Type Pass/Fail Failure analysis Cannot measure 0.001V ±0.28V at A/D IN. Description DAC U531 is programmed to generate +0.001 VDC at PRECOMP+. This signal follows the same path to the variable gain ampliÞer (VGA) as test 404.1. However, for this test AMP IN is positive.
Page 94 Troubleshooting Test 404.4 – Absolute value (x1 gain); +half-scale DAC output Type Pass/Fail Failure analysis Cannot measure 2.25V ±0.34V at A/D IN. Description DAC U531 is programmed to generate +2.25 VDC at PRECOMP+. This signal follows the same path as test 404.3. Measure +2.25V at A/D IN. Bit pattern DC_STB R1_STB...
Page 95 Troubleshooting Test 404.5 – Absolute value (x1 gain); +full-scale DAC output Type Pass/Fail Failure analysis Cannot measure 4.33V ±0.4V at A/D IN. Description DAC U531 is programmed to generate +4.33 VDC at PRECOMP+. This signal follows the same path as test 404.3. Measure +4.33V at A/D IN. Bit pattern DC_STB R1_STB...
Page 96 Troubleshooting Test 405.1 – Absolute value (x1 gain); large +DAC output Type Circuit Exercise Description DAC U531 is programmed to generate +0.51 VDC at PRECOMP+. The signal at PRE- COMP+ is routed to ACF via R560 and U532 (DAC line pulled low). The signal at ACF is then switched through multiplexer U511.
Page 97 Troubleshooting Test 405.2 – Absolute value x10 gain comparison; large +DAC output Type Pass/Fail Failure analysis Voltage at A/D IN not the same as test 405.1. Description DAC U531 is programmed to generate +0.51 VDC at PRECOMP+. That signal is then applied to ACF through R560 and U532 (DAC line pulled low).
Page 98 Troubleshooting Test 405.3 – Absolute value x10 gain comparison; small +DAC Output Type Circuit Exercise Description This test is the same as test 405.1 except that DAC U531 is programmed to generate +0.190 VDC at PRECOMP+. As in test 405.1, measure the actual voltage value at A/D IN (around +0.190V) and compare it to the measurement in the next test.
Page 99 Troubleshooting Test 405.4 – Absolute value x10 gain comparison; small +DAC output Type Pass/Fail Failure analysis Voltages at A/D IN not the same as test 405.3. Description This test is the same as test 405.2 except that DAC U531 is programmed to generate +0.190 VDC at PRECOMP+.
Page 100 Troubleshooting Test 405.5 – Absolute value x10 gain comparison; small –DAC output Type Circuit Exercise Description This test is the same as test 405.1 except that DAC U531 and Op Amp pair U528 are set up to generate -0.210 VDC at PRECOMP+. As in test 405.1, measure the actual voltage value at A/D IN (around -0.210V) and compare it to the measurement in the next test.
Page 101 Troubleshooting Test 405.6 – Absolute value x10 gain comparison; small –DAC output Type Pass/Fail Failure analysis Voltage at A/D IN not the same as test 405.5. Description DAC U531 is programmed to generate -0.210 VDC at PRECOMP+. This signal follows the same path to the variable gain ampliÞer (VGA) as test 405.2.
Page 102 Troubleshooting Test 405.7 – Absolute value x10 gain comparison; large –DAC output Type Circuit Exercise Description This test is the same as test 405.1 except that DAC U531 is programmed to generate -0.490 VDC at PRECOMP+. As in test 405.1, measure the actual voltage value at A/D IN (around -0.490V) and compare it to the measurement in the next test.
Page 103 Troubleshooting Test 405.8 – Absolute value x10 gain comparison; large –DAC output Type Pass/Fail Failure analysis Voltage a A/D IN not the same as test 405.7. Description This test is the same as test 405.6 except that DAC U531 is programmed to generate -0.490 VDC at PRECOMP+.
Page 104 Troubleshooting Test 406.1 – Test buffer; measure DAC output for test 406.6 Type Circuit Exercise Description DAC U531 is programmed to provide -1.13 VDC at PRECOMP+. The signal at PRE- COMP+ is routed to ACF via R560 and U532 (DAC line pulled low). The signal at ACF is then switched through multiplexer U511.
Page 105 Troubleshooting Test 406.2 – Test buffer output (-1.13V) Type Circuit Exercise Description DAC U531 is programmed to generate -1.13 VDC at PRECOMP+. The signal at PRE- COMP+ is routed to ACF via R560 and U532 (DAC line pulled low). ACF is routed to AMP IN through U526, Q516, and the AC input buffer.
Page 106 Troubleshooting Test 406.3 – Read test buffer for test 406.6 Type Circuit Exercise Description Same as test 406.2 except the value is read and stored for use for the comparison calcu- lation in test 406.6. Bit pattern DC_STB R1_STB R2_STB Registers Registers Registers...
Page 107 Troubleshooting Test 406.4 – Test buffer; read DAC output for test 406.6 Type Circuit Exercise Description This test is the same as test 406.1 except that DAC U531 is programmed to generate -0.01 VDC at PRECOMP+. Measure the actual voltage value at A/D IN (around -0.01V). This DAC voltage value is measured and stored.
Page 108 Troubleshooting Test 406.5 – Test buffer output (-0.01V) Type Circuit Exercise Description This test is the same as test 406.2 except that DAC U531 is programmed to generate -0.01 VDC at PRECOMP+. Measure the voltage at A/D IN. The computed voltage level at A/D IN is as follows: = |(A×4.8446)+B| A/D IN where;...
Page 109 Troubleshooting Test 406.6 – Voltage comparison Type Pass/Fail Failure analysis Voltage comparison is not less than 500mV. Description Same as test 406.5 except the value is stored and used for the comparison calculation in this test. The measurement compares the DAC voltages to the test buffer voltages. The comparison is calculated as follows: ) ×...
Page 110 Troubleshooting Test 407.1 – Front end; 2V range Type Pass/Fail Failure analysis Cannot measure 7V ±0.15V at A/D IN. Description The signal at BUFF is routed through R233, K503, K500, the input protection circuit and Q513 to the input buffer (Q512 and U520). The buffered signal is tied to AMP IN. The signal at AMP IN is then routed to the variable gain ampliÞer (VGA) and, being positive, follows the non-inverting x1 path that consists of R530, Q509, Q507, U519, R531, U509, Q501, and U516 to pin 12 of multiplexer U511.
Page 111 Troubleshooting Test 407.2 – Front end; 200V range Type Pass/Fail Failure analysis Cannot measure 0.7V ±0.2V at A/D IN. Description VRIN is buffered by U517 and tied to BUFF. The signal at BUFF is routed through R233 to pin 1 of NET1 (R557). The voltage at pin 4 of NET1 is routed through U526 (DCF pulled low) and Q516, and applied to the input buffer (Q512 and U520).
Page 112 Troubleshooting Test 407.3 – Front end; 750V range Type Pass/Fail Failure analysis Cannot measure 0.14V ±0.04V at A/D IN. Description VRIN is buffered by U517 and tied to BUFF. The signal at BUFF is routed through R233 to pin 1 of NET1 (R557). The voltage at pin 4 of NET1 is routed through U526 (DCF pulled low) and Q516, and applied to the input buffer (Q512 and U520).
Page 113 Troubleshooting Test 408.1 – ÷200 correction factor; circuit setup for test 408.2 Type Circuit Exercise Description The DAC (U531) is programmed with Ò1sÓ and OUT A is routed to C554. The signal at BUFF is routed through R233 and applied to NET1 (R557). The signal at pin 4 of NET1 is routed through U526 (DCF pulled low) and Q516, and applied to the input buffer (Q512 and U520).
Page 114 Troubleshooting Test 408.2 – ÷200 correction factor; signal stored for test 408.3 Type Circuit Exercise Description The SELFTEST control line turns on Q518 driving pin 4 of NET1 (R557) to ground. At the same time, the SELFTEST control line and multivibrator U503 generates a pulse that turns on Q510 allowing the signal to be stored on C529.
Page 115 Troubleshooting Test 408.3 – ÷200 correction factor; setup for test 408.5 and A/D measurement for test 408.6 Type Circuit Exercise Description The DAC (U531) is programmed with Ò0sÓ (full compensation) and OUT A is routed to C554. The signal at BUFF is routed through R233 and applied to NET1 (R557). The voltage at pin 4 of NET1 is routed through U526 (DCF pulled low) and Q516, and ap- plied to the input buffer (Q512 and U520).
Page 116 Troubleshooting Test 408.4 – ÷200 correction factor Type Circuit Exercise Description Same as Test 408.3, but no measurement taken. Bit pattern DC_STB R1_STB R2_STB Registers Registers Registers U801 U307 U505 U800 U305 U500 U300 U302 U530 U303 U501 Note: Tables 2-10 through 2-12 provide functional descriptions of the register bits. 2-103...
Page 117 Troubleshooting Test 408.5 – ÷200 correction factor; signal stored for test 408.6 Type Circuit Exercise Description The SELFTEST control line turns on Q518 driving the pin 4 of NET1 (R557) to ground. At the same time, the SELFTEST control line and multivibrator U503 generates a pulse that turns on Q510 allowing the signal to be stored on C529.
Page 118 Troubleshooting Test 408.6 – ÷200 correction factor; signal comparisons Type Pass/Fail Failure analysis The measurement in step 408.3 is not less than the measurement in step 408.6. Description Same as test 408.2. Measure the output at A/D IN. Bit pattern DC_STB R1_STB R2_STB...
Page 119 Troubleshooting Test 409.1 – ÷750 correction factor; circuit setup for test 409.2 Type Circuit Exercise Description The DAC (U531) is programmed with Ò1sÓ and OUT A is routed to C556. The signal at BUFF is routed through R233 and applied to NET1 (R557). The signal at pin 4 of NET1 is routed through U526 (DCF pulled low) and Q516, and applied to the input buffer (Q512 and U520).
Page 120 Troubleshooting Test 409.2 – ÷750 correction factor; signal stored for test 409.3 Type Circuit Exercise Description The SELFTEST control line turns on Q518 driving the signal on pin 4 of NET1 (R557) to ground. At the same time, the SELFTEST control line and multivibrator U503 gener- ates a pulse that turns on Q510 allowing the signal to be stored on C529.
Page 121 Troubleshooting Test 409.3 – ÷750 correction factor; setup for test 409.5 and A/D measurement for test 409.6 Type Circuit Exercise Description The DAC (U531) is programmed with Ò0sÓ and OUT A is routed to C556. The rest of this test is the same as test 408.3. Measure the output at A/D IN.
Page 122 Troubleshooting Test 409.4 – ÷750 correction factor Type Circuit Exercise Description Same as test 408.3 but no measurement taken. Bit pattern DC_STB R1_STB R2_STB Registers Registers Registers U801 U307 U505 U800 U305 U500 U300 U302 U530 U303 U501 Note: Tables 2-10 through 2-12 provide functional descriptions of the register bits. 2-109...
Page 123 Troubleshooting Test 409.5 – ÷750 correction factor; signal stored for test 409.6 Type Circuit Exercise Description The SELFTEST control line turns on Q518 driving pin 4 of NET1 (R557) to ground. At the same time, the SELFTEST control line and multivibrator U503 generates a pulse that turns on Q510 allowing the signal to be stored on C529.
Page 124 Troubleshooting Test 409.6 – ÷750 correction factor; signal comparisons Type Pass/Fail Failure analysis The measurement in step 409.3 is not less than the measurement is step 409.6. Description Same as test 409.2. Measure the output at A/D IN. Bit pattern DC_STB R1_STB R2_STB...
Page 125 Troubleshooting Test 410.1 – True RMS converter Type Pass/Fail Failure analysis Cannot measure 7V ±0.18V at A/D IN. Description VRIN is buffered by U517 and tied to BUFF. The signal at BUFF is routed through R233, K503, K500, the input protection circuit and Q513 to the input buffer (Q512 and U520). The buffered signal is tied to AMP IN.
Page 126 Troubleshooting Test 411.1 – Filter; true RMS Type Pass/Fail Failure analysis Cannot measure 7V ±0.18V at A/D IN. Description VRIN is buffered by U517 and tied to BUFF. The signal at BUFF is routed through R233, K503, K500, the input protection circuit and Q513 to the input buffer (Q512 and U520). The buffered signal is tied to AMP IN.
Page 127 Troubleshooting Test 411.2 – Filter; variable gain ampliﬁer Type Pass/Fail Failure analysis Cannot measure 7V ±0.16V at A/D IN. Description VRIN is buffered by U517 and tied to BUFF. The signal at BUFF is routed through R233, K503, K500, the input protection circuit and Q513 to the input buffer (Q512 and U520). The buffered signal is tied to AMP IN.
Page 128 Troubleshooting Test 412.1 – AC amps switch Type Pass/Fail Failure analysis Cannot measure 1.7V ±0.3V at A/D IN. Description The 9.2mA ohms source is turned on to dump current through switch U323 (ACAL pulled low) to the amps protection diodes (CR305 and CR309). The three diode voltage drop is routed through U317 (/200uA pulled low), U320 (/ACA pulled low), U510 (REL3 pulled low), U526 and Q516 to the input buffer (Q512 and U520).
Page 129 Troubleshooting 2-116...
Page 130 Þrmware. The information in this section explains how to disas- Instrument re-assembly  Provides some gen- semble the Model 2001. Also discussed are handling eral guidelines to follow when re-assembling the and cleaning considerations as well as the procedure to Model 2001.
Page 131: Solder Repairs
Use the following precautions to avoid damaging To remove the case cover, refer to drawing 2001-054 them: and perform the following steps: 1.
Page 132: Analog Board Top Shield Removal
The top shield (shown in IEEE connector. drawing 2001-050) is secured to the analog board by a 2. Unfasten PC-Board  Remove the following single screw. To remove the top shield, simply loosen the screw and carefully lift the shield out of the chassis.
Page 133: Analog Board
J1027 on the The analog board is removed through the top of the digital board. Return the chassis to the right-side- chassis (see drawing 2001-051). Perform the following up position. steps to remove the analog board: 6.
Page 134: Front Panel Disassembly
The cooling fan, which is mounted to the rear panel of the chassis (see drawing 2001-060), does not need to be NOTE removed in order to clean the Þlter. To clean the Þlter, refer to paragraph 1.4.
Page 135: Instrument Re-Assembly
The following assembly drawings are provided to as- CAUTION sist in disassembly and re-assembly of the instrument. Also, the Keithley part numbers for most mechanical EPROM U611 is a static sensitive de- parts are provided in these drawings. vice. Be sure to adhere to the han-...
Page 136: Replaceable Parts
Circuit description (if applicable) ¥ Keithley part number Parts lists The following parts lists for the Model 2001 are inte- grated with the component layouts and schematic dia- Factory service grams: If the instrument is to be returned to Keithley Instru-...
Page 137: Table
Replaceable Parts Table 4-1 Model 2001 A/D board, parts list Circuit Keithley Desig. Description Part No. CHOKE 21-030-J CH-55 DIODE, ZENER, 6.4V, IN5479 DZ-73-1 SOCKET, 68-PIN QUAD SO-128-68 C800-805,807,809,815, CAP,.1UF, 20%,50V,CERAMIC(1206) C-418-.1 819,820,830 C808,818 CAP,1UF,20%,50V, CERAMIC C-237-1 C812,814,824,826-829 CAP, 10UF,20%, 25V, TANTALUM (D7243)
Page 138 IC,OP-AMP,OPA602AP IC-703 U810,811 IC, OP-AMP,LT1097 IC-803 U812 IC, DUAL D-TYPE F/F, 74HC74(SOIC) IC-773 U813 IC, OPA177GS (SOIC) IC-960 VR801 DIODE,ZENER 6.4V,IN4579 (DO-7) DZ-73 Y800 OSCILLATOR CMOS, 7.68 MHZ CR-31 ** Order present Þrmware revision level for main CPU (i.e., 2001-802-A05).
Page 139 Replaceable Parts...
Page 140: Table
Replaceable Parts Table 4-2 Model 2001 analog board, parts list Circuit Keithley Desig. Description Part No. COM CONN,TEST POINT CS-553 CONTACT, FUSE 2001-314 FUSE HOLDER FH-32 HEAT SINK (USE WITH Q301,302,U102,107,108) HS-41 L.E.D. MOUNT (USE WITH Q529,530) MK-21-1 SPRING, COMPRESSION...
Page 141 Replaceable Parts Table 4-2 (continued) Model 2001 analog board, parts list Circuit Keithley Desig. Description Part No. C522 CAP,10PF,10%,1000V,CERAMIC C-64-10P C529 CAP, 10000PF, 20%, 63V, POLY-FILM C-471-10000P C531 CAP,22PF,10%,1000V,CERAMIC C-64-22P C533,578 CAP,100PF,10%,1000V,CERAMIC C-64-100P C539,543,584-586,588-590, CAP,.1UF, 20%,50V,CERAMIC(1206) C-418-.1 597,599 C544,571,201,202,427 CAP, .01uF, 20%, 50V, CERAMIC (1206) C-418-.01...
Page 142 Replaceable Parts Table 4-2 (continued) Model 2001 analog board, parts list Circuit Keithley Desig. Description Part No. E300 SURGE ARRESTOR, CG3-1.5L SA-4 F100 FUSE, .5A, 250V FU-71 F300 FUSE, 2A,250V, FAST-BLO(5X20MM) FU-48 J1002 CONN, MOLEX, 3-PIN CS-772-3 J1008-1011,J1017-1021 CRIMP CONTACT ROUND...
Page 143 Replaceable Parts Table 4-2 (continued) Model 2001 analog board, parts list Circuit Keithley Desig. Description Part No. Q506,511 TRANS,N-CHAN FET, BUK 456-1000B (TO-220) TG-247 Q510 TRANS, N-CHAN JFET, SST4391 (SOT-23) TG-250 Q512 TRANS, N-CHAN. DUAL JFET, U441 TG-235 Q514 TRANS, N-CHAN JFET SMP4338(SOT-23)
Page 144 Replaceable Parts Table 4-2 (continued) Model 2001 analog board, parts list Circuit Keithley Desig. Description Part No. R227,261-264,281,283,284, RES,1K,5%,125MW,METAL FILM(1206) R-375-1K 288,289 R228,240 RES,4.7K,5%,125MW,METAL FILM(1206) R-375-4.7K R229 RES, 470,5%, 125MW, METAL FILM(1206) R-375-470 R231,286 RES, 620, 5%, 250mW, METAL FILM (1210)
Page 145 Replaceable Parts Table 4-2 (continued) Model 2001 analog board, parts list Circuit Keithley Desig. Description Part No. R365 RES, 78.7K, .1%, .2W, WIREWOUND R-406-78.7K R366 RES,1M,0.1%,1/4W,METAL FILM R-433-1M R367 RES,22M,5%,1/4W,COMPOSITION OR FILM R-76-22M R368 RES, 4.99K, 1%, 125mW,METAL FILM (1206) R-391-4.99K...
Page 146 Replaceable Parts Table 4-2 (continued) Model 2001 analog board, parts list Circuit Keithley Desig. Description Part No. R527,535,565 RES,7.5K,5%,125MW,METAL FILM(1206) R-375-7.5K R530 RES NET,250K,9.34K,1K,10.233K,15K,7K TF-226 R531 RES NET, 1K,1K TF-227 R533 RES, 4.99K, 1%, 125mW,METAL FILM (1206) R-391-4.99K R538,540,545 RES,10K,5%,125MW,METAL FILM(1206)
Page 147 Replaceable Parts Table 4-2 (continued) Model 2001 analog board, parts list Circuit Keithley Desig. Description Part No. U304,306,309,310,316 IC, QUAD COMPARATOR,LM339D (SOIC) IC-774 U308,334 IC, TRI-2CH MULTI/DEMUX, 4053 (SOIC) IC-770 U311-315 IC,OPTOCOUPLER,TLP582 IC-689 U317 IC, CMOS ANAL. SWITCH, DG411DY(SOIC) IC-785...
Page 148 Replaceable Parts Table 4-2 (continued) Model 2001 analog board, parts list Circuit Keithley Desig. Description Part No. VR100 DIODE, ZENER 22V, BZX84C22 (SOT-23) DZ-86 VR101 DIODE, ZENER 6.2V, BZX84B6V2 (SOT-23) DZ-87 VR102 DIODE, ZENER, 39V, MLL4716(MLL-34) DZ-95 VR300,304 DIODE,ZENER 5.1V, BZX84C5V1 (SOT-23)
Page 149 Replaceable Parts 4-14...
Page 150: Table
Replaceable Parts Table 4-3 Model 2001 digital board, parts list Keithley Circuit Desig. Description Part No. CLIP, GROUND 2001-352B CONN,BERG CS-339 SOCKET (USE WITH U608) SO-134-32 SOCKET, 44 PIN QUAD (USE WITH U611) SO-128-44 VACUUM FLUORESCENT DISPLAY DD-51C C101 CAP,1,20%,250V,ALUMINUM ELECTROLYTIC...
Page 151 Replaceable Parts Table 4-3 (continued) Model 2001 digital board, parts list Keithley Circuit Desig. Description Part No. Q101,102 TRANS,NPN TG-271 Q602-607 TRANS,N CHAN MOSPOW FET,2N7000 (TO-92) TG-195 Q608 TRANS,N-CHANNEL FET,TN06L TG-216 TG-216 R101 RES,240,250MW,METAL FILM(1210) R-376-240 R102 RES,1K,250MW,METAL FILM(1210) R-376-1K...
Page 152 DIODE, ZENER, 8.2V, MMBZ5237 (SOT-23) DZ-92 VR602,603 DIODE,ZENER,4.7V,IN4732A(D0-41) DZ-67 W602,603 JUMPER J-15 W605,606 CONN,3 PIN CS-339-3 W606 CONNECTOR, JUMPER CS-476 Y602 CRYSTAL, 16MHZ CR-30-16M Y603 OSCILLATOR CMOS 4,MHZ(SMT) CR-34 ** Order present Þrmware revision level for main CPU (i.e., 2001-801-A05). 4-17...
Page 153 Replaceable Parts 4-18...
Page 154: Table
HANDLE TO CASE FASTENER FA-230-2 HOLDER, FERRITE 2001-367 IEEE CONNECTOR, HARDWARE KIT CS-713 INSULATOR, REGULATOR 2001-359 JACK, CURRENT INPUT 2001-312 LEXAN, ANALOG BOTTOM SHIELD (FOR 2001-339) 2001-340 LEXAN SHIELD, CHASSIS LEFT 2001-326 LEXAN SHIELD, CHASSIS-RIGHT 2001-336 LINE CORD CO-7 LU-88 MOUNTING EAR, LEFT...
Page 155 Replaceable Parts Table 4-4 (continued) Model 2001 miscellaneous, parts list Keithley Description Part no. ÒDÓ CONN. REAR OF DIGITAL BOARD SCREWLOCK, FEMALE CS-725 #12 PVC- 4 1/8Ó FAN, DC BRUSHLESS, 12VDC, 100mA FN-26 CONN, AC RECEPTACLE (LINE FILTER) LF-6-1 BANANA JACK, PUSH-IN, RED...
Page 156 Model 2001 Speciﬁcations...
Page 157 20V calibrator will reduce For ±2°C of last AC self cal. calibration uncertainty, and can thereby improve total 2001 accuracy for measurements up to 50% of range. Refer to the 2001 calibration procedure for details. TYPICAL ACCURACIES Accuracy can be specified as typical or warranted.
Page 158 DC VOLTS DCV INPUT CHARACTERISTICS AND ACCURACY DEFAULT ACCURACY TEMPERATURE COEFFICIENT ± (ppm of reading + ppm of range) ± (ppm of reading + ppm of range)/°C FULL RESO- RESO- INPUT ± 5°C RANGE SCALE LUTION LUTION RESISTANCE 5 Minutes 24 Hours 90 Days 1 Year...
Page 159 DCV PEAK SPIKES MEASUREMENT 90 Days, ± 2°C from last AC self-cal ± (% of reading+% of range) REPETITIVE SPIKES ACCURACY TEMPERATURE COEFFICIENT 750kHz– ± (% of reading+% of range)/°C 1kHz– 10kHz– 30kHz– 50kHz– 100kHz– 300kHz– 500kHz– ± 2°C RANGE 0–1kHz 10kHz 30kHz...
Page 160 AC VOLTS (cont’d) NORMAL MODE RMS 90 Days, ± 2°C from last AC self-cal for 1% to 100% of range ± (% of reading + % of range) RANGE 20–50Hz 50–100Hz 0.1–2kHz 2–10kHz 10–30kHz 30–50kHz 50–100kHz 100–200kHz 0.2–1MHz 1–2MHz 200 mV 0.25+0.015 0.07+0.015 0.03+0.015...
Page 161 AC VOLTS (cont’d) SETTLING CHARACTERISTICS: COMMON MODE REJECTION: For 1kΩ imbalance in either lead: >60dB for line frequency ±0.1%. Normal Mode (rms, avg.) <300ms to 1% of step change MAXIMUM VOLT•Hz PRODUCT: 2 × 10 <450ms to 0.1% of step change V•Hz (for inputs above 20V).
Page 162 OHMS (cont’d) 2-WIRE RESISTANCE READING RATES 20Ω, 200Ω, 2kΩ, and 20kΩ Ranges 10,12 READINGS/SECOND WITH MEASUREMENT DEFAULT READINGS/SECOND TO MEMORY READINGS/SECOND TO IEEE-488 TIME STAMP TO IEEE-488 NPLC APERTURE BITS DIGITS Auto Zero Off Auto Zero On Auto Zero Off Auto Zero On Auto Zero Off Auto Zero On 167 ms (200 ms)
Page 163 The DC in-circuit current measurement function allows a user to measure the current through a wire or a circuit board trace without breaking the circuit. When the In-Circuit Current Measurement function is selected, the 2001 will first perform a 4-wire resistance measurement, then a voltage measurement, 10Ω...
Page 164 AC AMPS (cont’d) ACI READING RATES READINGS/SECOND WITH MEASUREMENT DEFAULT READINGS/SECOND TO MEMORY READINGS/SECOND TO IEEE-488 TIME STAMP TO IEEE-488 NPLC APERTURE BITS DIGITS Auto Zero Off Auto Zero On Auto Zero Off Auto Zero On Auto Zero Off Auto Zero On 167 ms (200 ms) ⁄...
Page 165 OPERATING SPEED The following diagram illustrates the factors that determine a DMM’s reading rate. COMMAND RECEIVE AND INTERPRET SPEED GPIB FASTEST TYPICAL SLOWEST Command Time per character 0.16 ms 0.28 ms 0.66 ms Characters per second 6250 3751 1515 Command Command Receive and Receive and Stored...
Page 166 OPERATING SPEED (cont’d) RANGE CHANGE SPEED AUTO ZERO OFF AUTO ZERO ON RATE RATE FUNCTION From TIME (per second) TIME (per second) 200mV, 2V 4.5 ms 3.1 ms 200V, 1000V 8.0 ms 8.6 ms 200mV, 2V, 20V 200mV, 2V, 20V 4.5 ms 200V, 1000V 200mV, 2V...
Page 167 EXTENDED MEMORY / NON-VOLATILE MEMORY OPTIONS DATA STORAGE SIZE ⁄ -Digit SETUP STORAGE MODEL (Bytes) ⁄ -Digit w/Time Stamp Type Number Type 2001 volatile non-volatile 2001/MEM1 7,000 1,400 non-volatile non-volatile 2001/MEM2 128k 30,000 6,000 non-volatile non-volatile Speciﬁcations subject to change without notice.
Page 168 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...

Keithley 2001 Repair Manual

1 Routine Maintenance

2 Troubleshooting

4 Replaceable Parts

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