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Model 2000

Multimeter

Repair Manual

Contains Servicing Information

W ARRANTY

Keithley Instruments, Inc. warrants this product to be free from defects in material and workmanship for a period of 3 years from date of shipment.

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

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

T o e xercise this w arranty, write or call your local K eithley representati v e, or contact K eithle y headquarters in Cleveland, Ohio. You will be given prompt assistance and return instructions. Send the product, transportation prepaid, to the indicated service facility. Repairs will be made and the product returned, transportation prepaid. Repaired or replaced products are warranted for the balance of the original warranty period, or at least 90 days.

LIMIT A TION OF W ARRANTY

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

THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. THE REMEDIES PROVIDED HEREIN ARE B UYER’S SOLE AND EXCLUSIVE REMEDIES.

NEITHER KEITHLEY INSTRUMENTS, INC. NOR ANY OF ITS EMPLOYEES SHALL BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF ITS INSTRUMENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS, INC., HAS BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH DAMAGES. SUCH EXCLUDED DAMAGES SHALL INCLUDE, BUT ARE NOT LIMITED TO: COSTS OF REMOVAL AND INSTALLATION, LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY PERSON, OR DAMAGE TO PROPERTY.

Keithley Instruments, Inc. • 28775 Aurora Road • Cleveland, OH 44139 • 440-248-0400 • Fax: 440-248-6168 • http://www.k eithley.com

BELGIUM: Keithley Instruments B.V. Bergensesteenweg 709 • B-1600 Sint-Pieters-Leeuw • 02/363 00 40 • Fax: 02/363 00 64 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 B.P. 60 • 3, allée des Garays • 91122 Palaiseau Cédex • 01 64 53 20 20 • Fax: 01 60 11 77 26 GERMANY: Keithley Instruments GmbH Landsberger Strasse 65 • D-82110 Germering • 089/84 93 07-40 • Fax: 089/84 93 07-34 GREAT BRITAIN: Keithley Instruments Ltd The Minster • 58 Portman Road • Reading, Berkshire RG30 1EA • 0118-9 57 56 66 • Fax: 0118-9 59 64 69 INDIA: Keithley Instruments GmbH Flat 2B, WILOCRISSA • 14, Rest House Crescent • Bangalore 560 001 • 91-80-509-1320/21 • Fax: 91-80-509-1322 ITALY: Keithley Instruments s.r.l. Viale S. Gimignano, 38 • 20146 Milano • 02/48 30 30 08 • Fax: 02/48 30 22 74 NETHERLANDS: Keithley Instruments B.V. Postbus 559 • 4200 AN Gorinchem • 0183-635333 • Fax: 0183-630821 SWITZERLAND: Keithley Instruments SA Kriesbachstrasse 4 • 8600 Dübendorf • 01-821 94 44 • Fax: 01-820 30 81 TAIWAN: Keithley Instruments Taiwan 1 Fl. 85 Po Ai Street • Hsinchu, Taiwan, R.O.C. • 886-3572-9077• Fax: 886-3572-9031

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Model 2000 Multimeter

Repair Manual

Cleveland, Ohio, U.S.A.

Second Printing, March 1997

Document Number: 2000-902-01 Rev. B

Manual Print History

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

Revision A (Document Number 2000-902-01).................................................................May 1995

Revision B (Document Number 2000-902-01).............................................................. March 1997

All Keithley product names are trademarks or registered trademarks of Keithley Instruments, Inc. Other brand names are trademarks or registered trademarks of their respective holders.

Safety Precautions

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

This product is intended for use by qualiﬁed personnel who recognize shock hazards and are familiar with the safety precautions required to avoid possible injury. Read the operating information carefully before using the product.

The types of product users are:

Responsible body is the individual or group responsible for the use and maintenance of equipment, and for en-

suring that operators are adequately trained.

Operators use the product for its intended function. They must be trained in electrical safety procedures and

proper use of the instrument. They must be protected from electric shock and contact with hazardous live circuits.

Maintenance personnel perform routine procedures on the product to keep it operating, for example, setting

the line voltage or replacing consumable materials. Maintenance procedures are described in the manual. The procedures explicitly state if the operator may perform them. Otherwise, they should be performed only by service personnel.

Service personnel are trained to work on live circuits, and perform safe installations and repairs of products.

Only properly trained service personnel may perform installation and service procedures.

Exercise extreme caution when a shock hazard is present. Lethal voltage may be present on cable connector jacks or test ﬁxtures. The American National Standards Institute (ANSI) states that a shock hazard e xists when voltage levels greater than 30V RMS, 42.4V peak, or 60VDC are present. A good safety practice is to expect

that hazardous voltage is present in any unknown circuit before measuring.

Users of this product must be protected from electric shock at all times. The responsible body must ensure that users are prevented access and/or insulated from every connection point. In some cases, connections must be exposed to potential human contact. Product users in these circumstances must be trained to protect themselves from the risk of electric shock. If the circuit is capable of operating at or above 1000 volts, no conductive part

of the circuit may be exposed.

As described in the International Electrotechnical Commission (IEC) Standard IEC 664, digital multimeter measuring circuits (e.g., Keithley Models 175A, 199, 2000, 2001, 2002, and 2010) measuring circuits are Installation Category II. All other instruments’ signal terminals are Installation Category I and must not be connected to mains.

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

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

For maximum safety, do not touch the product, test cables, or any other instruments while power is applied to the circuit under test. ALWAYS remove power from the entire test system and discharge an y capacitors before: connecting or disconnecting cables or jumpers, installing or removing switching cards, or making internal changes, such as installing or removing jumpers.

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

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

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

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

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

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

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

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

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

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

Instrumentation and accessories shall not be connected to humans. Before performing any maintenance, disconnect the line cord and all test cables.

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

T o clean the instrument, use a damp cloth or mild, water based cleaner . Clean the exterior of the instrument only . Do not apply cleaner directly to the instrument or allow liquids to enter or spill on the instrument.

T able of Contents

Routine Maintenance

Introduction..........................................................................................1-2

Setting line voltage and replacing fuse................................................1-2

AMPS fuse replacement......................................................................1-4

T roubleshooting

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

Repair considerations...........................................................................2-3

Power-on test.......................................................................................2-3

Front panel tests...................................................................................2-4

Principles of operation.........................................................................2-5

Display board checks.........................................................................2-11

Power supply checks..........................................................................2-11

Digital circuitry checks......................................................................2-12

Analog signal switching states...........................................................2-13

Built-In T est overview .......................................................................2-18

Built-In T est documentation..............................................................2-22

Disassembly

Introduction..........................................................................................3-2

Handling and cleaning.........................................................................3-3

Static sensitive devices........................................................................3-4

Assembly drawings..............................................................................3-4

Case cover removal..............................................................................3-5

Changing trigger link lines ..................................................................3-6

Motherboard removal ..........................................................................3-7

Front panel disassembly ......................................................................3-8

Main CPU ﬁrmware replacement........................................................3-9

Removing power components ...........................................................3-10

Instrument re-assembly......................................................................3-12

Replaceable Parts

Introduction..........................................................................................4-2

Parts lists..............................................................................................4-2

Ordering information...........................................................................4-2

Factory service.....................................................................................4-3

Component layouts..............................................................................4-3

Speciﬁcations

............................................................................................................A-1

List of Illustrations

Routine Maintenance

Power module......................................................................................1-3

T roubleshooting

Power supply block diagram...............................................................2-6

Digital circuitry block diagram ...........................................................2-7

Analog circuitry block diagram...........................................................2-9

Disassembly

Trigger link line connections...............................................................3-6

Ω

Ω 2/ Ω

Ω

List of T ables

Routine Maintenance

Fuse rating ...........................................................................................1-3

T roubleshooting

Power supply circuits...........................................................................2-7

Display board checks.........................................................................2-11

Power supply checks..........................................................................2-11

Digital circuitry checks......................................................................2-12

DCV signal switching........................................................................2-13

ACV and FREQ signal switching......................................................2-13

2 signal switching...........................................................................2-14

4 signal switching...........................................................................2-14

DCA signal switching........................................................................2-15

ACA signal switching........................................................................2-15

DCV signal multiplexing and gain....................................................2-16

ACV and ACA signal multiplexing and gain.....................................2-16

DCA signal multiplexing and gain....................................................2-16

2 signal multiplexing and gain........................................................2-16

4 signal multiplexing and gain........................................................2-17

Circuit section location for switching devices...................................2-17

Built-In T est summary.......................................................................2-19

4 reference switching................................................................2-15

Routine

Maintenance

1-2 Routine Maintenance

Introduction

The information in this section deals with routine type maintenance that can be performed by

the operator. This information is arranged as follows:

• Setting line voltage and replacing fuse — Explains how to select the alternate po wer line voltage setting, and how to replace a blown power line fuse.

• Amps fuse replacement — Explains how to replace a blown current fuse.

Setting line voltage and replacing fuse

A rear panel fuse located next to the A C receptacle (in the power module) protects the power line input of the instrument. If the line voltage setting needs to be changed or the line fuse needs to be replaced, perform the following steps.

W ARNING Disconnect the line cord at the rear panel and remove all test leads connected to the instru-

ment (front and rear) before replacing the line fuse or changing the line voltage setting.

1. Place the tip of a ﬂat-blade screwdriv er into the po wer module by the fuse holder assembly (see Figure 1-1). Gently push in and to the left. Release pressure on the assembly and its internal spring will push it out of the power module.

2. Remove the fuse and replace it with the type listed in Table 1-1.

CAUTION For continued protection against ﬁre or instrument damage, only replace

fuse with the type and rating listed. If the instrument repeatedly blows fuses, locate and correct the cause of the trouble before replacing the fuse.

3. If conﬁguring the instrument for a different line voltage, remo ve the line voltage selector from the assembly and rotate it to the proper position. When the selector is installed into the fuse holder assembly, the correct line voltage appears inverted in the window.

4. Install the fuse holder assembly into the power module by pushing it in until it locks in place.

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

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

Routine Maintenance 1-3

Figure 1-2

Power module

Model 2000

1000V

350V

PEAK

500V

PEAK

SENSE

INPUT

Ω 4W

MADE IN

U.S.A.

IEEE-488

(CHANGE IEEE ADDRESS

TRIGGER

LINK

3 5

VMC

4 6

EXT TRIG

FUSE LINE

250mAT

100 VAC

(SB)

120 VAC 220 VAC

125mAT

240 VAC

(SB)

FROM FRONT PANEL)

RS232

120

LINE RATING

50, 60 400HZ

17 VA MAX

Line Voltage Selector

Fuse

Spring

Fuse Holder Assembly

Table 1-1

Fuse rating

Line voltage Fuse rating Keithley part no.

100/120V 220/240V

0.25A slow-blow 5 × 20mm

0.125A slow-blow 5

20mm

FU-96-4 FU-91

220

240

120

100

Window

1-4 Routine Maintenance

AMPS fuse replacement

WARNING Make sure the instrument is disconnected from the power line and other equipment before

replacing the AMPS fuse.

1. Turn off the power and disconnect the power line and test leads.

2. From the front panel, gently push in the AMPS jack with your thumb and rotate the fuse carrier one-quarter turn counter-clockwise. Release pressure on the jack and its internal spring will push the fuse carrier out of the socket.

3. Remove the fuse and replace it with the same type 3A, 250V, fast blow: Keithley part number FU-99-1.

CAUTION Do not use a fuse with a higher current rating than speciﬁed or instrument

damage may occur. If the instrument repeatedly blows fuses, locate and correct the cause of the trouble before replacing the fuse.

4. Install the new fuse by reversing the procedure.

Troubleshooting

2-2 Troubleshooting

Introduction

WARNING The information in this section is intended for qualiﬁed service personnel.

Some of these procedures may expose you to hazardous voltages. Do not per form these hazardous procedures unless you are qualiﬁed to do so.

This section of the manual will assist you in troubleshooting the Model 2000. Included are self-tests, test procedures, troubleshooting tables, and circuit descriptions. It is left to the discretion of the repair technician to select the appropriate tests and documentation needed to troubleshoot the instrument. This section is arranged as follows:

• Repair considerations — Covers some considerations that should be noted before making any repairs to the Model 2000.

• Power-on test — Describes the tests that are performed on memory elements each time the instrument is turned on.

• Front panel tests — Provides the procedures to test the functionality of the front panel keys and the display.

• Principles of operation — Provides support documentation for the various troubleshooting tests and procedures. Included is some basic circuit theory for the display board, power supply, digital circuitry and analog circuitry.

• Display board checks — Provides display board checks that can be made if front panel tests fail.

• Power supply checks — Provides po wer supply checks that can be made if the inte grity of the power supply is questionable.

• Digital circuitry checks — Provides some basic checks for the digital circuitry.

• Analog signal switching states — Provides tables to check switching states of various relays, FETs, analog switches and the A/D multiplexer for the basic measurement functions and ranges.

• Built-in test overview — Summarizes the b uilt-in tests, which can be used to test and e xercise the various digital and analog circuits.

• Built-in test documentation — Provides a detailed analysis of each built-in test.

Troubleshooting 2-3

Repair considerations

Before making any repairs to the Model 2000, be sure to read the following considerations.

CAUTION The PC-boards are built using surface mount techniques and require special-

ized equipment and skills for repair. If you are not equipped and/or qualiﬁed, it is strongly recommended that you send the unit back to the factory for repairs or limit repairs to the PC-board replacement level. Without proper equipment and training, you could damage a PC-board beyond repair.

1. Repairs will require various degrees of disassembly. However, it is recommended that the Front Panel Tests and Built-In-Test be performed prior to any disassembly. The disassembly instructions for the Model 2000 are contained in Section 3 of this manual.

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

3. When working inside the unit and replacing parts, be sure to adhere to the handling precautions and cleaning procedures explained in Section 3.

4. Many CMOS devices are installed in the Model 2000. These static-sensitive devices require special handling as explained in Section 3.

5. Anytime a circuit board is removed or a component is replaced, the Model 2000 must be recalibrated.

Power-on test

During the power-on sequence, the Model 2000 will perform a checksum test on its EPROM (U156 and U157) and test its RAM (U151 and U152). If one of these tests fails the instrument will lock up.

▲

2-4 Troubleshooting

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 ev ent of a test failure, refer to “Display Board Checks” for details on troubleshooting the display board.

KEY test

The KEY test allows you to check the functionality of each front panel key. Perform the following steps to run the KEY test:

1. Press SHIFT and then TEST to access the self-test options.

2. Use the

3. Press ENTER to start the test. When a ke y is pressed, the label name for that key is displayed to indicate that it is functioning properly. When the key is released, the message “NO KEY PRESS” is displayed.

4. Pressing EXIT tests the EXIT key . Ho we v er, the second consecutive press of EXIT aborts the test and returns the instrument to normal operation.

or ▼ key to display “TEST: KEY”.

DISP test

cent display is working properly. Perform the following steps to run the display test:

The display test allows you to verify that each pixel and annunciator in the vacuum ﬂuores-

1. Press SHIFT and then TEST to access the self-test options.

2. Use the

3. Press ENTER to start the test. There are four parts to the display test. Each time ENTER is pressed, the next part of the test sequence is selected. The four parts of the test sequence are as follows: A. All annunciators are displayed.

B. The pixels of each digit are sequentially displayed. C. The 12 digits (and annunciators) are sequentially displayed. D. The annunciators located at either end of the display are sequentially displayed.

4. When ﬁnished, abort the display test by pressing EXIT. The instrument returns to normal operation.

or ▼ key to display “TEST: DISP”.

Principles of operation

The following information is provided to support the troubleshooting tests and procedures

covered in this section of the manual. Refer to the following block diagrams:

Block Diagrams: Figure 2-1 — Power supply block diagram

Figure 2-2 — Digital circuitry block diagram Figure 2-3 — Analog circuitry block diagram

Display board

Troubleshooting 2-5

Microcontroller

U401 is the display board microcontroller that controls the display and interprets key data. The microcontroller uses three internal, peripheral I/O ports for the various control and read functions.

Display data is serially transmitted to the microcontroller from the digital section via the TXB line to the microcontroller RDI terminal. In a similar manner, key data is serially sent back to the digital section through the RXB line via TDO. The 4MHz clock for the microcontroller is generated by crystal Y401.

Display

DS401 is the display module, which can display up to 12 alpha-numeric characters and the various annunciators.

The display uses a common multiplexing scheme with each character refreshed in sequence. U402 and U403 are the drivers for the display characters and annunciators. Note that data for the drivers are serially transmitted from the microcontroller (MOSI and PC1).

Filament voltage for the display is derived from the power supply transformer (F1 and F2). The display drivers require +37VDC and +5VDC, which are supplied by U144 (+5VD) and U101 (+37V).

2-6 Troubleshooting

Key matrix

The front panel keys (S401-S430) are organized into a row-column matrix to minimize the number of microcontroller peripheral lines required to read the keyboard. A k ey is read by strobing the columns and reading all rows for each strobed column. K e y down data is interpreted by the display microcontroller and sent back to the main microprocessor using proprietary encoding schemes.

Power supply

The following information provides some basic circuit theory that can be used as an aid to troubleshoot the power supply. A block diagram of the power supply is shown in Figure 2-1.

Figure 2-1

Power supply block diagram

+5VD

D Common

+37V

D Common

+15V A Common

-15V

+5V, +5VRL

A Common

Fuse

Power Switch

Line

Voltage

Switch

Power

Transformer

CR104

C128, C156

U144

CR116, CR117

C104, C108

U101

CR102 C131, C148 U119, U125

CR103

C146 U124

AC power is applied to the AC power module receptacle (J1009). Power is routed through the line fuse and line voltage selection switch of the power module to the power transformer. The power transformer has a total of four secondary windings for the various supplies.

AC voltage for the display ﬁ laments is taken from a power transformer secondary at F1 and F2, and then routed to the display board.

Each DC supply uses a bridge rectiﬁer, a capaciti v e ﬁlter arrangement and a regulator . Table 2-1 summarizes rectiﬁer, ﬁlter and regulator circuits for the various supplies.

Table 2-1

Power supply circuits

Supply Rectiﬁer Filter Regulator

Troubleshooting 2-7

Digital circuitry

Figure 2-2

Digital circuitry block diagram

+5VD +37V +15V

-15V +5V, +5VRL

CR104 CR116, CR117 CR102 CR102 CR103

C128, C156 C104, C108 C148 C131 C146

U144 U101 U125 U119 U124

Refer to Figure 2-2 for the following discussion on digital circuitry.

RAM

U151, U152

OUT

Data IN Data OUT

Analog

Circuitry

(See Figure 2-3)

XADTX XADCLK XADTS

XADRX

Scan Control

U146, U164

Trigger

P T

AT101

U150 U155

NVRAM

U136

ADTX ADCLK ADTS

ADRXB

TRIG IN TRIG OUT

ROM

U156, U157

68306

µP

U135

Display Board

Controller

U401

XTAL Y101

RS-232

U159

GPIB

U158, U160,

U161

Keypad

RS-232

Port

Display

DS401

IEEE-488

Bus

Trigger

Link

2-8 Troubleshooting

Microprocessor

U135 is a 68306 microprocessor that oversees all operating aspects of the instrument. The MPU has a 16-bit data bus and provides an 18-bit address b us. It also has parallel and serial ports for controlling various circuits. For example, the RXDA, TXDA, RXDB and TXDB lines are used for the RS-232 interface.

The MPU clock frequency of 14.7456MHz is controlled by crystal Y101. MPU RESET is performed momentarily (through C241) on power-up by the +5VD power supply.

Memory circuits

ROMs U156 and U157 store the ﬁrmware code for instrument operation. U157 stores the D0D7 bits of each data word, and U156 stores the D8-D15 bits.

RAMS U151 and U152 provide temporary operating storage. U152 stores the D0-D7 bits of each data word, and U151 stores the D8-D15 bits.

Semi-permanent storage facilities include NVRAM U136. This IC stores such information as instrument setup and calibration constants. Data transmission from this device is done in a serial fashion.

RS-232 interface

Serial data transmission and reception is performed by the TXDB and RXDB lines of the MPU. U159 provides the necessary voltage level conversion for the RS-232 interface port.

IEEE-488 interface

U158, U160 and U161 make up the IEEE-488 interface. U158, a 9914A GPIA, takes care of routine bus overhead such as handshaking, while U160 and U161 provide the necessary buffering and drive capabilities.

T rigger circuits

Buffering for Trigger Link input and output is performed by U146. T rigger input and output is controlled by the IRQ4 and PB3 lines of the MPU. U164 provides additional logic for the trigger input to minimize MPU control overhead.

At the factory, trigger output is connected to line 1 of the Trigger Link connector (resistor R267 installed). Trigger input is connected to line 2 of the T rigger Link connector (resistor R270 installed).

Analog circuitry

Refer to Figure 2-3 for the following discussion on analog circuitry.

Ω

Troubleshooting 2-9

Figure 2-3

Analog circuitry block diagram

AMPS

DCA ACA

AC Switching

K102, U102, U103, U105,

U112, U118, U111, U110

ACV,

FREQ

SSP*

Ohms I-Source U133, Q123, Q125, Q124, Q126, Q119,

Q120, U123

Scanner Control

Gain

DCV

OHMS

DCV & Ohms

Switching K101, Q104, Q105, Q108, Q113, U115

X1 Buffer U113

BUFCOM

A/D

MUX &

Gain U163, U166 U129, U132

ADC

U165

Digital

Circuitry

(See Figure 2-2)

INPUT

R117, Q109, Q114, Q136

SENSE

Scanner Output

Scanner

Inputs

K103, R158, R205

Q101, Q102

DCV

Divider

DCV/100

Q121, U126

Scanner

Option

*Solid State Protection

Current

Shunts

X1 Buffer

INPUT HI

INPUT HI protection is provided by the SSP (solid state protection) circuit. The SSP is primarily made up of Q101 and Q102. An overload condition opens Q101 and Q102. This disconnects the analog input signal from the rest of the analog circuit.

Note that for the 100VDC and 1000VDC ranges, Q101 and Q102 of the SSP are open. The DC voltage signal is routed through the DCV Divider (Q114 and Q136 on) to the DCV switching circuit.

AMPS input

The ACA or DCA input signal is applied to the Current Shunt circuit, which is made up of K103, R158 and R205. For the 10mADC range, 10.1 put. Relay K103 is energized (on) to select the shunts. For all other DCA ranges, and all ACA ranges, 0.1

(R158) is shunted across the input (K103 off).

The A CA signal is then sent to the A C Switching & Gain circuit, while the DCA signal is routed directly to the A/D MUX & Gain circuit.

(R158 + R205) is shunted across the in-

2-10 Troubleshooting

Signal switching

Signal switching for DCV and OHMS is done by the DCV & Ohms Switching circuit. FETs Q113, Q105, Q104 and Q108 connect the DCV or ohms signal to the 2-5 through 2-8 show the switching states of these FETs for the v arious DCV and OHMS ranges.)

Note that the reference current for OHMS is generated by the Ohms I-Source circuit. For 4wire ohms measurements, SENSE LO is connected to the circuit by turning on Q121.

Signal switching and gain for ACV, FREQ and ACA is done by the AC Switching & Gain circuit, which is primarily made up of K102, U102, U103, U105, U112, U118, U111 and U110. Tables 2-6 and 2-11 show the switching states for these AC signals. Note that U111 is used for frequency adjustment. The states of these analog switches vary from unit to unit.

1 buffer (U113). (Tables

Multiplexer and A/D converter

All input signals, except FREQ, are routed to the A/D MUX & Gain circuit. The multiplex er (U163) switches the various signals for measurement. In addition to the input signal, the multiplexer also switches among reference and zero signals at v arious phases of the measurement cycle.

When the input signal is selected by the MUX, it is ampliﬁed by U132 and U166. Tables 212 through 2-16 identify the input signal lines (S3, S4, S6 or S7) of the multiplexer for the various functions and ranges. These tables also provide the switch states of U129, which determine the gain for U132 and U166.

The multiplexed signals of the measurement cycle are routed to the A/D Converter (U165) where it converts the analog signals to digital form. The digital signals are then routed through an opto-isolator to the MPU to calculate a reading.

Display board checks

If the front panel DISP test indicates that there is a problem on the display board, use Table

2-2. See “Principles of Operation” for display circuit theory.

Table 2-2

Display board checks

Step Item/component Required condition Remarks

Troubleshooting 2-11

Front panel DISP test.

P1005, pin 5

P1005, pin 9

U401, pin 1

U401, pin 43

U401, pin 32

U401, pin 33

Power supply checks

Power supply problems can be checked out using Table 2-3. See “Principles of Operation”

for circuit theory on the power supply.

Table 2-3

Power supply checks

Step Item/component Required condition Remarks

Line fuse

Line voltage

Line power

U144, pin2

U101, pin 7

U125, pin 3

U119, pin 3

U124, pin 3

Verify that all pixels operate. +5V +/-5% +37V +/-5% Goes low brieﬂy on power up, then goes low. 4MHz square wave. Pulse train every 1msec. Brief pulse train when front panel key pressed.

Check continuity. 120V/240V as required. Plugged into live receptacle, power on. +5V +/-5% +37V +/-5% +15V +/-5%

-15V +/-5% +5V +/-5%

Use front panel display test. Digital +5V supply. Display +37V supply. Microcontroller RESET.

Controller 4MHz clock. Control from main processor. Key down data sent to main processor.

Remove to check. Check power module position. Check for correct power-up sequence. +5VD, referenced to Common D. +37V, referenced to Common D. +15V, referenced to Common A.

-15V, referenced to Common A. +5VRL, referenced to Common A.

2-12 Troubleshooting

Digital circuitry checks

Digital circuit problems can be checked out using Table 2-4. See “Principles of Operation” for digital circuit.

Table 2-4

Digital circuitry checks

Step Item/component Required condition Remarks

Power-on test

U152 pin 16

U152 pin 32

U135 pin 48

U135, lines A1 thru A23

U135, lines D1 thru D15

U135 pin 44

U159 pin 13

U159 pin 14

U158 pins 34-42

U158 pins 26-31

U158 pin 24

U158 pin 25

U135 pin 84

U135 pin 91

U135 pin 90

U135 pin 89

RAM OK, ROM OK.

Digital common.

+5V Low on power-up, then goes high. Check for stuck bits. Check for stuck bits.

14.7456MHz Pulse train during RS-232 I/O. Pulse train during RS-232 I/O. Pulse train during IEEE-488 I/O. Pulses during IEEE-488 I/O.

Low with remote enabled. Low during interface clear. Pulse train. Pulse train. Pulse train. Pulse train.

Verify that RAM and ROM are functional. All signals referenced to digital common. Digital logic supply. MPU RESET line.

MPU address bus. MPU data bus. MPU clock. RS-232 RX line. RS-232 TX line. IEEE-488 data bus. IEEE-488 command lines. IEEE-488 REN line. IEEE-488 IFC line. ADRXB ADTX ADCLK ADTS

Analog signal switching states

Tables 2-5 through 2-11 provide switching states of the various relays, FETs and analog switches for the basic measurement functions and ranges. These tables can be used to assist in tracing an analog signal from the input to the A/D multiplexer.

Table 2-5

DCV signal switching

Range Q101 Q102 Q114 Q136 Q109 K101* Q113 Q105 Q104 Q108 Q121

OFF

10V

100V

OFF

Pin 3 switched to Pin 4

OFF OFF ON ON

100mV

1000V

*K101 set states: Pin 8 switched to Pin 7

OFF OFF OFF OFF OFF

SET SET SET SET SET

Troubleshooting 2-13

OFF

Table 2-6

ACV and FREQ signal switching

Range Q101 Q102 K101* K102*

RESET

10V 100V 750V

ON ON ON ON ON

ON ON ON ON

RESET RESET RESET RESET

100mV

*K101 and K102 reset states: Pin 8 switched to Pin 9

K101 and K102 set states: Pin 8 switched to Pin 7

RESET RESET SET SET SET

Pin 3 switched to Pin 2

Pin 3 switched to Pin 4

U103 pin 8

ON ON OFF OFF OFF

U103 pin 9

ON ON OFF OFF OFF

U105 pin 9

OFF OFF ON ON ON

U105 pin 8

OFF OFF OFF OFF ON

U103 pin 16

OFF ON OFF ON OFF

U103 pin 1

ON OFF ON OFF OFF

U105 pin 1

ON OFF ON OFF OFF

U111 pin 16

OFF OFF OFF OFF OFF

2-14 Troubleshooting

Table 2-7

Ω

2 signal switching

Range Q101 Q102 Q114 Q136 Q109 K101* K102* Q113 Q105 Q104 Q108 Q121

100 Ω

ON ON ON

10k Ω

100k Ω

10M Ω

100M Ω

*K101 set states: Pin 8 switched to Pin 7

K102 reset states: Pin 8 switched to Pin 9

ON ON ON ON

OFF

Pin 3 switched to Pin 4

Pin 3 switched to Pin 2

OFF OFF OFF OFF OFF ON ON

SET SET SET SET SET SET SET

RESET RESET RESET RESET RESET RESET RESET

OFF OFF OFF OFF OFF OFF OFF

ON ON ON ON ON ON ON

1k Ω

1M Ω

1k Ω

1M Ω

OFF

Table 2-8

Ω

4 signal switching

Range Q101 Q102 Q114 Q136 Q109 K101* Q113 Q105 Q104 Q108 Q121

OFF

100 Ω

10k Ω

100k Ω

10M Ω

100M Ω

*K101 set states: Pin 8 switched to Pin 7

Pin 3 switched to Pin 4

OFF OFF OFF OFF OFF OFF

OFF

OFF OFF OFF OFF OFF ON ON

SET SET SET SET SET SET SET

ON ON ON ON ON OFF OFF

OFF OFF OFF OFF ON ON

OFF OFF OFF OFF OFF OFF

ON ON ON ON ON ON

Table 2-9

Ω

4 reference switching

100 Ω

10k Ω

U133 /.7V

OFF OFF OFF ON ON OFF OFF

Range

100k Ω

10M Ω

100M Ω

U133

Q123 Q125 Q124 Q126 Q120

/7V

OFF

OFF OFF ON ON ON ON ON

ON ON ON ON ON OFF OFF

1k Ω

Troubleshooting 2-15

1M Ω

Table 2-10

DCA signal switching

Range K103

10mA

1A 3A

OFF OFF OFF

100mA

Table 2-11

ACA signal switching

Range K103

1A3AOFF

OFFONONONON

T ables 2-12 through 2-16 can be used to trace the analog signal through the A/D multiplexer (U163) to the ﬁnal ampliﬁer stage. These tables show the MUX lines (S3, S4, S6, S7) that are selected for measurement during the SIGNAL phase of the multiplexing cycle. Also included are switching states of analog switches (U129) that set up the gain for the ﬁnal ampliﬁer stage (U166).

U105 pin 16

U105 pin 1

U111 pin 16

OFFONOFF

U105 pin 8

OFF

U103 pin 16

OFF OFF

U103 pin 1

OFF OFF

2-16 Troubleshooting

Table 2-12

DCV signal multiplexing and gain

× 10 × 1 ×

Range

100mV

10V

100V

1000V

Signal (U163)

S4 S4 S4 S4 S4

U129 pin 1

OFF OFF ON OFF ON

U129 pin 8

OFF ON OFF ON OFF

U129 pin 9

ON OFF OFF OFF OFF

Table 2-13

ACV and ACA signal multiplexing and gain

Range

All S3 ON OFF OFF ×1

Signal (U163)

U129 pin 1

U129 pin 8

U129 pin 9

Table 2-14

DCA signal multiplexing and gain

Range

10mA

100mA

1A 3A

Signal (U163)

S6 S6 S6 S6

U129 pin 1

OFF OFF OFF OFF

U129 pin 8

OFF OFF OFF ON

U129 pin 9

ON ON ON OFF

Gain (U166)

100

×1

Gain (U166)

×100 ×100 ×100 ×10

Table 2-15

Ω

2 signal multiplexing and gain

Range

100Ω

1kΩ

10kΩ

100kΩ

1MΩ

10MΩ

100MΩ

Signal (U163)

S4 S4 S4 S4 S4 S4 S4

U29 pin 1U129

OFF OFF OFF OFF ON ON ON

pin 8

OFF ON ON ON OFF OFF OFF

U129 pin 9

ON OFF OFF OFF OFF OFF OFF

Gain (U166)

×100 ×10 ×10 ×10 ×1 ×1 ×1

Table 2-16

Ω

4 signal multiplexing and gain

Troubleshooting 2-17

100Ω

1kΩ

10kΩ

1MΩ

Signal (U163)

S4 then S7 S4 then S7 S4 then S7 S4 then S7 S4 then S7 S4 then S7 S4 then S7

Range

100kΩ

10MΩ

100MΩ

Figure 2-3 provides a block diagram of the analog circuitry. Table 2-17 is provided to show where the various switching devices are located in the block diagram.

U129 pin 1

OFF OFF OFF OFF ON ON ON

U129 pin 8

OFF ON ON ON OFF OFF OFF

U129 pin 9

ON OFF OFF OFF OFF OFF OFF

Gain (U166)

×100 ×10 ×10 ×10 ×1 ×1 ×1

Table 2-17

Circuit section locations for switching devices

Switching devices

Q101, Q102 Q114, Q136, Q109 K101, Q113, Q105, Q104, Q108 Q121 K102, U103, U105, U111 U133, Q123, Q125, Q124,

Q126, Q120

K103 U163, U129

Analog circuit section (see Figure 2-3)

SSP (Solid State Protection) DCV Divider DCV & Ohms Switching Sense LO AC Switching & Gain

Ohms I-Source Current Shunts A/D Mux & Gain

2-18 Troubleshooting

Built-In T est overview

Built-In Test is used to test and exercise v arious circuits and components. The Built-In Tests are listed in Table 2-18. Many of the tests are actual pass/fail type tests, while others are circuit exercises that are used for subsequent tests. Each Built-In Test can be run manually. After a test is manually run, operation is “frozen” to allow the technician to troubleshoot the circuit.

Using Built-In T est

There are several ways to run the Built-In Test, including the following recommended sequence:

1. Run the AUTO bit test (see “AUTO Testing”) and note the ﬁrst (lowest numbered) test that has failed. Always address the lo west numbered test failure ﬁrst because that f ailure could cause subsequent tests to fail.

2. Familiarize yourself with the failed circuit. See “Built-In Test Documentation” for troubleshooting information. Be sure to read the documentation for the complete series. For example, if test 202.4 fails, read the documentation for all 202 series tests.

3. Manually run the test that failed (see “MANUAL T esting”). Keep in mind that many of the pass/fail type tests require that one or more circuit exercise tests be run ﬁrst. Using the manual step looping mode will “freeze” instrument operation after a test is run.

4. After manually running the test, use the test documentation and your troubleshooting expertise to locate the problem.

5. After repairing the instrument, start again at step 1 to check the integrity of the repair and to see if there are any other failures.

Table 2-18

Built-In Test summary

Test Circuit tested

Troubleshooting 2-19

Bank 100

100.1

100.2

101.1

101.2

101.3

Bank 200

200.1

200.2

201.1

201.2

Bank 300

300.1

301.1

301.2

302.1

302.2

303.1

303.2

304.1

Bank 400

400.1

400.2

400.3

401.1

401.2

401.3

402.1

402.2

402.3

403.1

403.2

403.3

Bank 500

500.1

500.2

Bank 600

600.1

600.2

601.1

601.2

601.3

A/D

A/D A/D TestCal TestCal TestCal

REF/MUX

Reference Reference A/D Mux Lo A/D Mux Lo

DC/OHM

Front End Lo Hi Ohms Hi Ohms 2W Sense 2W Sense Lo Ohm Path Lo Ohm Path Input /100

VAC

Non Inv Path Non Inv Path Non Inv Path Invert Path Invert Path Invert Path Non Inv /10 Non Inv /10 Non Inv /10 Non Inv Bex2 Non Inv Bex2 Non Inv Bex2

SENSE

4W Sense 4W Sense

AMP/OHM

Ohm/Amp Ohm/Amp Amp Shunt Amp Shunt Amp Shunt

2-20 Troubleshooting

AUTO testing

1. Press SHIFT and then TEST to access the self-test options.

2. Use the ▲ or ▼ key to display “TEST: BUILT-IN” and press ENTER.

3. Use the ▲ or ▼ key to display “BIT: AUTO” and press ENTER.

4. Use the , , ▲ or ▼ key to display the bank of tests that you wish to run and press

5. Use the , , ▲ or ▼ key to display one of the following FAULT options:

6. Press ENTER and go to step A or B:

7. After the tests are ﬁnished, any failures are displayed. With the ”FAILS” message dis-

8. When ﬁnished, use the EXIT key to back out of the test menu structure.

ENTER. Test BANK selections include: FULL Perform all tests.

A/D Perform tests on A/D converter. REF/MUX Perform tests on reference and multiplexer circuitry. DC/OHM Perform tests on DC and ohm circuitry. VAC Perform tests on AC volts circuitry. SENSE Perform tests on sense circuitry. AMP/OHM Perform tests on amp and ohm circuitry.

PAUSE The tests will stop (pause) when a failure (FAULT) occurs. CONT The tests will not stop (continue) when a failure occurs.

A. If the PAUSE fault option was selected, the tests will start immediately. The tests

stop at a failure (F AULT) and displays the test number of the failure. Press ENTER to continue the tests or press EXIT to abort the tests.

B. If the CONT fault option was selected, use the ▲ or ▼ key to display one of the

following REPEAT options and press ENTER to start the tests: NO Perform the speciﬁed tests and stop.

YES Continuously repeat the speciﬁed tests. When a failure occurs, the “FAULT” message will be displayed. If the YES repeat

option was selected, use the EXIT key when ready to stop the tests.

played, use the , , ▲ or ▼ key to scroll through the test numbers of the failures.

MANUAL testing

1. Press SHIFT and then TEST to access the self-test options.

2. Use the ▲ or ▼ key to display “TEST: BUILT-IN” and press ENTER.

3. Use the ▲ or ▼ key to display “BIT: MANUAL” and press ENTER.

4. Use the and keys, or the ▲ and ▼ keys to display the desired test series number.

For example, if you wish to run test 302.2, display the series 302 test number as shown: MANUAL: 302

5. With the desired test series number displayed, press ENTER.

6. Use the , , ▲ or ▼ key to display one of the following looping modes and press

ENTER: SINGLE — Performs all the tests in the speciﬁed series. The instrument displays the

number of the test being run. If a failure occurs, the “FAUL T” message appears and stays on for the remainder of the tests in the series. This testing process automatically stops after the last test in the series is completed. This test process can also be stopped by pressing EXIT . When EXIT is pressed, any test in process will be allo wed to ﬁnish before aborting the testing process.

CONTINUOUS — This looping mode continuously repeats all the tests in the speciﬁed

series until the testing process is manually stopped. If a failure occurs, the “FAUL T” message appears and stays on for the remainder of the tests in the series. This test process can be stopped by pressing EXIT . When EXIT is pressed, any test in process will be allowed to ﬁnish before aborting the testing process.

STEP — Used to perform one test at a time. Each press of the ENTER key performs the

displayed test. If a failure occurs, the “FAULT” message appears for that test. The instrument automatically aborts the testing process after the last test in the series is run. If you do not wish to run all the tests in the series, simply press EXIT after the desired test is run.

7. After the tests are ﬁnished, any failures are displayed. With the ”FAILS” message dis-

played, use the , , ▲ or ▼ key to scroll through the test numbers of the failures.

8. When ﬁnished, use the EXIT key to back out of the test menu structure.

Troubleshooting 2-21

2-22 Troubleshooting

Built-In T est documentation

The following paragraphs provide a detailed description of each Built-In Test. Refer to “Built-In Test overvie w” for basic information on ho w to use Built-In T ests. The following documentation is provided for each test:

• Test Identiﬁcation — Includes test bank, number and name.

• Input Requirements — Indicates the required state of the input terminals for the test. Note that input requirements are displayed by the Model 2000 when Built-In Test is run.

• Expected Value and Limits — Provides the measurement or reading value (and limits) that is expected for the test as explained in the “Description”.

• Fault Message — For pass/fail type tests, a message is pro vided to summarize the cause of the failure.

• Description — Provides a description of circuit being tested. In general, all components in the tested circuit could be the cause of a failure.

• Bit Patterns — Provides the logic states of key shift re gisters. After a test is manually run, you can check the registers for the correct logic levels.

NOTE The letter “v” in a bit pattern indicates a “don’t care” condition.

Troubleshooting 2-23

TEST BANK: A/D

T est 100.1 — A/D

Bank A/D Inputs Open Expected V alue 153661550 counts Limits 1200000 counts Fault Message NO A/D COMM

Description

Bit patterns

This A/D test uses the def ault conditions of the ADC w ord and the ACDC word. This sets up the front end of the instrument to a stable conﬁguration. The MUX word is applied to register U130 which sets lines A0, A1 and A2 of U163 high. This bit pattern selects the S8 input, which connects signal LO to the D output.

Signal LO is then connected to op amp U166 which is conﬁgured for gain with feedback through mux switch U129 pin 2 to 3. Signal LO is then connected to the A/D at A/D_IN.

In the ﬁrst tests the value is in the form of counts. Signal LO is converted to counts in the A/D and then compared to a zero by-design value. This test checks the functionality of the A/D converter. If the 100 series tests fail, all other tests will be invalid. Measure 0V at A/D-IN. Failures could be the A/ D MUX U163, the A/D buffer U132 and associated circuitry, or almost any component in the A/D section. Primary checks should be the references and power supplies, then the control circuit U165.

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

00101111

87654321

—U134—

1v10000v

—U130—

11111101

87654321 —U121— 01110010

ACDC_STB

MUX_STB

2-24 Troubleshooting

T est 100.2 — A/D

Bank A/D Inputs Open Expected V alue <none speciﬁed> Limits 100 counts Fault Message SIGNAL NOISY

Description

Bit patterns

This test has the identical setup as the 100.1 test. Signal LO is connected to the A/D circuit for ten readings and a min/max comparison is done to ensure that all readings are within 100 counts of each other . The test is to check for noise. The failures are the same as in test 100.1.

Primary checks should be the references and power supplies. Secondary tests are the op amps of the integrator (U138 and U137), gain op amp U142, and the zero-cross comparator U145.

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

00101111

87654321

—U134—

1v10000v

—U130—

11111101

87654321

—U121—

01110010

ACDC_STB

MUX_STB

Troubleshooting 2-25

T est 101.1 — TESTCAL

Bank A/D Expected V alue <none speciﬁed> Limits <none speciﬁed> Inputs Open

Description

Bit patterns

TESTCAL is a way to calibrate the unit with internal references so that the remaining tests can be displayed in the form of voltages. Gi ven that there are errors in the internal references and in the A/D circuitry, the voltages on the display of the unit may vary from the value that is measured at A/D-IN with a calibrated test meter. The values on the display of the unit under test are values that are relative to the internal references.

This test has the same set up as the 100.1 and 100.2 tests. The A/D mak es a conversion of the signal zero and stores the v alue in the form of A/D counts to be used in the next phase of the test. There is no fault message for this test. Measure 0V at A/D-IN.

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

00101111

87654321

—U134—

1v10000v

—U130—

11111101

87654321 —U121— 01110010

ACDC_STB

MUX_STB

2-26 Troubleshooting

T est 101.2 — TESTCAL

Bank A/D Inputs Open Expected Value (101.2) - (101.1) = 76275970 counts Limits 1800000 Fault Message NO 7V AT A/D

Description

Bit patterns

This A/D test uses the def ault conditions of the ADC w ord and the ACDC word. This sets up the front end of the instrument to a stable conﬁguration. The MUX word is applied to register U130 which sets the lines of U163 as follows; A0 and A1 lo w, A2 high. This bit pattern selects the S5 input, which connects REFHI to the D output.

REFHI is then connected to op amp U166 which is conﬁgured for with feedback through mux switch U129 pin 2 to 3. The buffered value of REFHI is then connected to the A/D at A/D-IN.

A conversion is tak en in the form of A/D counts and compared to the v alue taken in test 101.1. The value in counts of test 101.2 minus the value in counts of test 101.1 yields a value that is compared to a v alue by-design for REFHI. If this value is within the limits, the REFHI reference, which is 7 volts, is considered acceptable. Measure 7V at A/D-IN. Failures could be the MUX (U163), or the reference circuit (U141) and the associated circuitry.

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

00101111

87654321

—U134—

1v10000v

—U130—

11001101

87654321

—U121—

01110010

1 gain

ACDC_STB

MUX_STB

Troubleshooting 2-27

T est 101.3 — TESTCAL

Bank A/D Inputs Open Expected V alue 1.03 volts Limits 0.06 volts Fault Message NO 1V AT A/D

Description

Bit patterns

This test uses the default conditions of the ADC word and the ACDC word. This sets up the front end of the instrument to a stable conﬁguration. The MUX word sets shift register U130 to disable U163 by setting line /EN low. The /EN line is also connected to pin 16 of U129 which closes the mux switch for pins 14 and 15. This connects the voltage between R189 and R185 (around 1.03 volts) to op amp U166, which is conﬁgured for feedback through U129 (pin 2 to 3). The buf fered value of the signal is then connected to the A/D at A/D-IN.

A conversion is tak en and compared to the calibration values in tests 101.1 and 101.2, and displayed as a voltage. Measure 1.03V at A/D-IN. Primary tests are on the resistor divider (R189, R185, and R188), the MUX U163, and the signal path from the resistor divider.

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

00101111

87654321

—U134—

1v10000v

—U130—

11111100

87654321 —U121— 01110010

1 gain with

ACDC_STB

MUX_STB

2-28 Troubleshooting

TEST BANK: REF/MUX

T est 200.1 — REFERENCE

Bank REF/MUX Inputs Open Expected V alue 1 volt Limits 0.1 volts Fault Message 1VREF/AD X10

Description

Bit patterns

The 7V REFHI signal is routed through R189 and R185, which forms a

0.014/1 voltage divider with R188. The 0.1V result (0.014 then applied to S1 of U163. The A0, A1 and A2 bit pattern on U163 is set to connect the S1 signal (0.1V) to the D output. The signal is then routed through R159, Q117 and R166 to the non-inverting input of op amp U166. A/D MUX (U166) is conﬁgured for on U129 analog switch; pins 6 to 7). Feedback resistors R309 and R310 conﬁgure the

87654321

—U106—

110v1111

10 gain. Measure 1V at AD_IN.

Bit pattern Register

87654321

—U109—

00101111

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

10 gain (/ × 10 control line is low turning

87654321

—U134—

1v10000v

—U130—

10000111

87654321

—U121—

01110010

7V = 0.1V) is

ACDC_STB

MUX_STB

T est 200.2 — REFERENCE

Bank REF/MUX Inputs Open Expected V alue 10 volts Limits 1 volt Fault Message AD X100

Troubleshooting 2-29

Description

Bit patterns

Same as test 200.1 except the A/D MUX is conﬁgured for × 100 gain (/

100 control line is low). The gain path is through U129 pin 10 to 11. Resis-

tor network R271 is used to conﬁgure the x100 gain. Measure 10V at AD_IN.

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

00101111

87654321

—U134—

1v10000v

—U130—

10001011

87654321 —U121— 01110010

ACDC_STB

MUX_STB

2-30 Troubleshooting

T est 201.1 — A/D MUX LO

Bank REF/MUX Inputs Open Expected V alue 0 volts Limits 0.0001 volts Fault Message SENSE LO 0

Description

Bit patterns

Signal LO is routed through R181 and Q122 (/LOMUXA control line high) into unity gain amp U126. Signal LO is then routed to S7 of U163. The A0, A1 and A2 bit pattern on U163 connects S7 to the D output, which then routes signal LO through Q117 to U166.

The A/D MUX (U166) is conﬁgured for closing U129; pin 2 to 3. Measure 0V at AD_IN.

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

00101111

87654321

—U134—

1v10000v

—U130—

11011101

1 gain (/ × 1 control line low) by

87654321

—U121—

01110010

ACDC_STB

MUX_STB

T est 201.2 — A/D MUX LO

Bank REF/MUX Inputs Open Expected V alue 0 volts Limits 0.0001 volts Fault Message MUX LO

Troubleshooting 2-31

Description

Bit patterns

This test is similar to test 201.1, except signal LO is routed through R274 to S8 of U163. Signal LO is then routed through Q117 to U166, which is conﬁgured for

87654321

—U106—

110v1111

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

1 gain. Measure 0V at AD_IN.

Bit pattern Register

87654321

—U109—

00101111

87654321

—U134—

1v10000v

—U130—

11111101

87654321 —U121— 01110010

ACDC_STB

MUX_STB

2-32 Troubleshooting

TEST BANK: DC/OHM

T est 300.1 — FRONT END LO

Bank DC/OHM Inputs Open Expected Value 0 volts Limits 0.01 volts Fault Message FRONT END LO

Description

Bit patterns

This test is for the DC volts front end LO path. Control line DIVLO is high making the U120 comparator output (pin 2) open collector. Q114 is on due to the gate being pulled low by R164. Signal LO is connected to SIG/100 through Q114 and divider R117.

The DIVT AP control line at U115 (pin 11) is pulled high to turn on Q108. This routes SIG/100 LO through Q108 to the unity gain buffer U113. The signal at the output of U113 is now called BUFCOM and goes through R314 to S4 of U163. It then goes to the A/D MUX which is conﬁ gured for Measure 0V at AD_IN.

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

00101111

87654321

—U134—

1v10000v

—U130—

10111101

87654321

—U121—

01110001

1 gain.

ACDC_STB

MUX_STB

T est 301.1 — HI OHMS

Bank DC/OHM Inputs Open Expected V alue 7 volts Limits 0.7 volts Fault Message 7V REFBOOT

Ω

Troubleshooting 2-33

Description

NOTE K101 and K102 are latching r elays. Any r eference to their contr ol line settings implies

that this setting, normally high (+5V), may be present for less than 100 milliseconds. Remember this if attempting to troubleshoot these parts, especially when running the BIT test in the MANUAL STEP mode.

+7V is generated by buffering REFHI with op amp U139. This +7V, which is used by the ohms circuit as a voltage reference, is switched by U133 (/7V control line low) to op amp U123 which is a unity gain buffer.

The +7V reference, now labeled REFBOOT, is routed through R272, Q109 (/HIOHM control line low), the 9.9M K101 (RESETK2 control line high), R304, Q104 (LOV control line high) to U113. The unity gain output of U113 (BUFCOM) then goes to the A/D MUX as in test 300.1 with a gain of

1. Measure +7V at AD_IN.

half of R117, Q101, Q102,

Bit patterns

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

00101111

87654321

—U134—

1v10001v

—U130—

10111101

87654321 —U121— 10000100

ACDC_STB

MUX_STB

2-34 Troubleshooting

T est 301.2 — HI OHMS

Bank DC/OHM Inputs Open Expected V alue 12.4 volts Limits 0.5 volts Fault Message 13.3 REFBOOT

Description

Bit patterns

This test is the same as 301.1 except that the +13.3V ohms reference is tested. The +13.3V reference is generated by the same circuit as the +7V reference. 14V is routed through Q130 and then applied to a 1K/10K divider which is part of R271. The +13.3V divider output is routed through analog switch U133 (/.7V control line low) to op amp U123. The remainder of the path is the same as test 300.1.

The expected voltage at AD_IN would be +13.3V except that at the source lead of Q104 (labeled SOURCE) there is a clamping circuit. Back-to-back 11V zener diodes VR105 and VR106, and photo-coupler U107 clamp the voltage at the SOURCE node to about +12.4V. Measure +12.4V at AD_IN.

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

00101111

87654321

—U134—

0v01001v

—U130—

10111101

87654321

—U121—

10000100

ACDC_STB

MUX_STB

T est 302.1 — 2W SENSE

Bank DC/OHM Inputs Open Expected V alue 7 volts Limits 0.7 volts Fault Message 2W SENSE 7V

Ω

Troubleshooting 2-35

Description

Bit patterns

The +7V reference is again switched to REFBOOT, and routed through R272, Q109, the 9.9M R115, R324 and L109, and then through R113, R107, R103, R108, and K101. At this point, the reference is labeled 2WSEN_I.

Reference 2WSEN_I is then routed through K102 (control line SETK1 high) to the 2WSEN_O node. This node then goes through Q105 (2W control line high), to U113 (BUFCOM) and to the A/D MUX with +7V at AD_IN.

87654321

—U106—

110v1111

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

half of divider R117, the parallel combination of

Bit pattern Register

87654321

—U109—

00011111

87654321

—U134—

0v10000v

—U130—

10111101

87654321 —U121— 10000010

1 gain. Measure

ACDC_STB

MUX_STB

2-36 Troubleshooting

T est 302.2 — 2W SENSE

Bank DC/OHM Inputs Open Expected V alue 12.4 volts Limits 0.5 volts Fault Message 2W SENSE 13V

Description

Bit patterns

Same as test 302.1 except the +13.3V reference is used. This v oltage does not go through the ohms zener clamp path but is clipped by the A/D circuit itself at about 12.4V due to the fact that 13.3V approaches the power supply limits of the op amps. Measure +12.4V at AD_IN.

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

00011111

87654321

—U134—

0v01000v

—U130—

10111101

87654321

—U121—

10000010

ACDC_STB

MUX_STB

T est 303.1 — LO OHM P A TH

Bank DC/OHM Inputs Open Expected V alue 7 volts Limits 0.7 volts Fault Message 7V SOURCE

Ω

Troubleshooting 2-37

Description

Bit patterns

This test uses the ohms circuit. The +7V reference is switched to REFBOOT by closing U133 (/7V line lo w). Q123 and Q125 are turned on by setting the OHMA control line high. +14V is applied directly to R194. Since Q123 is on, +7V appears on the other side of R194. As a result, the voltage drop across R194 (7.06k R194, Q125, Q119, CR114, and Q120 (/LOWOHM control line low).

The current (labeled OHM) then ﬂows through R304, U107, VR106, and VR105 to LO. The +7V reference is routed through Q104, to BUFCOM, and on to the A/D MUX with a gain of

87654321

—U106—

110v1111

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

87654321

—U109—

00101111

) is 7V. A current of 1mA therefore ﬂows through

1. Measure +7V at AD_IN.

Bit pattern Register

87654321

—U134—

0v10011v

—U130—

10111101

87654321 —U121— 01100100

ACDC_STB

MUX_STB

2-38 Troubleshooting

T est 303.2 — LO OHM P A TH

Bank DC/OHM Inputs Open Expected V alue 12.4 volts Limits 0.5 volts Fault Message 13.3V SOURCE

Ω

Description

Bit patterns

This test is similar to test 303.1. The +13.3V reference is switched to REFBOOT again by closing U133 pins 6 to 7. Q124 and Q126 are turned on by setting the OHMA control line low . +14V is applied to R195, and since Q124 is on, +13.3V appears on the other end of R195. The voltage across R195 (70.6K and Q120 (/LOWOHM control line low).

VR105 to LO. This is again the clamping circuit described in test 301.2. The +12.4V reference is routed through Q104, to BUFCOM, and on to the A/D MUX with a gain of

) is 0.7V. 10µA therefore ﬂows through R195, Q126, Q119, CR114,

The current (labeled OHM) then ﬂows through R304, U107, VR106, and

1. Measure +12.4V at AD_IN.

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

00101111

87654321

—U134—

0v01001v

—U130—

10111101

87654321

—U121—

01100100

ACDC_STB

MUX_STB

T est 304.1 — INPUT /100

Bank DC/OHM Inputs Open Expected V alue 7 volts Limits 0.7 volts Fault Message INP SIG/100

Troubleshooting 2-39

Description

Bit patterns

The ohms circuit current is set up the same as test 303.1. A 1mA current ﬂows into the OHM node but instead of ﬂowing into the clamping circuit, it ﬂows through K101 (RESETK2 control line high) through Q102, Q101, R117, and Q114 to LO.

Resistor R117 is a 100 to 1 divider. Therefore, 0.07V (7V/100) is seen at the SIG/100 node. Q108 is turned on to switch the 0.07V through U113 (BUFCOM) to the A/D MUX which is conﬁgured for +7V at AD_IN.

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

00101111

87654321

—U134—

1v10011v

—U130—

10111011

100 gain. Measure

87654321 —U121— 10110001

ACDC_STB

MUX_STB

2-40 Troubleshooting

TEST BANK: V AC

T est 400.1 — NON INV P A TH

Bank VAC Inputs Open Expected V alue <none speciﬁed> Limits <none speciﬁed> Fault Message <none>

Ω

Description

Bit patterns

This test places the ACV front end in the non-inverting conﬁguration.

Logic levels for this conﬁguration are as follows:

K102: /SETK1 low, /RESETK1 high U103: Pins 8 and 9 low U105: Pin 9 high

The signal path is from A CIN through K102 to the plus input of U102. Resistors R117 (9.9M feedback path for U102 is from the minus input through U103 (pins 6 and 7) to node A CFE. Node ACFE is connected to U112 through U103 (pin 1 low). Op amp U112 is conﬁgured for through U105 (pin 1 low). The signal is then coupled across C115 to U118. Analog switch U111 (pin 16 low) is closed to set up U118 for unity gain.

The output of U118 goes to U110 (TRMS conv erter) through the parallel combination of R129, C113 and C114. The output of the TRMS converter (OUT) is fed back through its own internal buffer. The buffer output signal (BUFF OUT) is then labeled AC_MED. The AC_MED signal is selected at U163 and fed to the A/D b uffer (U166) through Q117. The A/D buffer is set up for

1 gain through U129 (/ × 1 low). This test is a setup phase for the ne xt

test.

) and R146 (1.1M Ω ) to form a ÷ 10 at the input. The

10 gain. The output of U112 is routed

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

10011111

87654321

—U134—

1v01000v

—U130—

10011101

87654321

—U121—

01110000

ACDC_STB

MUX_STB

T est 400.2 — NON INV P A TH

Bank VAC Inputs Open Expected V alue 5.6 volts Limits 0.6 volts Fault Message NON INV PATH

Troubleshooting 2-41

Ω

Description

Bit patterns

The previous test sets up the circuit for this test. There is a routine in software that generates a waveform for the ACV tests. This is done by selecting the 13.3V reference by closing analog switch U133 (/.7V control line low). The reference is buffered by U123 is labeled REFBOOT.

The REFBOOT signal is switched into the front end through Q109 via U120 by toggling the /HIOHM line. This switching routine is done in ﬁrmware. Q114 and Q136 are turned ON (conducting to ground) by U120 (DIVLO control line low). The 100k to clean up the switched signal REFBOOT.

The signal path continues through Q101, Q102 and K101 to ACIN. The switched ACIN signal (coupled across C105) is applied to the circuit described in test 400.1 and the measurement is made.

The input signal switching stops while the A/D takes the reading. Signal switching continues after the reading is done. There are delays before the reading is taken to ensure that the ACV section and ﬁlters have enough time to reach a charged full scale reading. In this phase, the switched signal can be traced through the circuit described in test 400.1. Measure 5.6 volts DC at A/D_IN.

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

10011111

leg of R117 acts as a pull-up and pull-down

87654321

—U134—

1v01000v

—U130—

10011101

87654321 —U121— 01110000

ACDC_STB

MUX_STB

2-42 Troubleshooting

T est 400.3 — NON INV P A TH

Bank VAC Inputs Open Expected V alue <none speciﬁed> Limits <none speciﬁed> Fault Message <none>

Description

Bit patterns

This phase resets the circuit to a known state and turns the waveform signal off. Subsequent tests require that the A/D be in the normal operating mode.

Bit pattern Register

87654321

—U106—

101v0001

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

87654321

—U109—

10011111

87654321

—U134—

1v01000v

—U130—

10011101

87654321

—U121—

01110000

ACDC_STB

MUX_STB

Troubleshooting 2-43

T est 401.1 — INVERT P A TH

Bank VAC Inputs Open Expected V alue <none speciﬁed> Limits <none speciﬁed> Fault Message <none>

Description This test places the ACV front end in the inverting conﬁguration. Logic

levels for this conﬁguration are as follows:

K102: /SETK1 high, /RESETK1 low U103: Pins 8 and 9 high U105: Pin 9 low

Bit patterns

The signal path is from A CIN through C105, R104 and R105, which make

up a 1.1MΩ input resistance to the minus input of op amp U102. The plus input of U102 is connected to AC common through R146. Feedback for U102 is provided by R106 (11kΩ). The output gain for U102 (seen at A CFE) is ×0.001 (R106/(R117+R104+R105)).

The output of U102 (ACFE) is routed through U103 (pin 1 low) to U112

which is conﬁgured for ×10 gain. The signal then goes through U105 (pin 1 low) and is coupled across C115 to U118 which is conﬁgured for ×2 gain.

The output of U118 goes to the TRMS converter (U110) through the parallel combination of R129, C113 and C114. The output of the TRMS converter (OUT) is fed back through its own internal buffer. The buffer output signal (BUFF OUT) is then labeled AC_MED. The AC_MED signal is selected at U163 and fed to the A/D buffer (U166) through Q117. The A/D buffer is set up for ×1 gain through U129 (/×1 lo w). This test is a setup phase for the next test.

Bit pattern Register

87654321

—U106—

101v1101

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

87654321

—U109—

01101111

87654321

—U134—

1v01000v

—U130—

10011101

87654321 —U121— 01110000

ACDC_STB

MUX_STB

2-44 Troubleshooting

T est 401.2 — INVERT P A TH

Bank VAC Inputs Open Expected V alue 0.108 volts Limits 0.02 volts Fault Message INVERT PATH

Description The previous test sets up the circuit for this test. There is a routine in soft-

ware that generates a waveform for the ACV tests. This is done by selecting the 13.3V reference by closing analog switch U133 (/.7V control line low). The reference is buffered by U123 is labeled REFBOOT.

The signal path continues through Q101, Q102 and K101 to ACIN. The switched ACIN signal (coupled across C105) is applied to the circuit described in test 401.1 and the measurement is made.

Bit patterns

The input signal switching stops while the A/D takes the reading. Signal switching continues after the reading is done. There are delays before the reading is taken to ensure that the ACV section and ﬁlters have enough time to reach a charged full scale reading. In this phase,the switched signal can be traced through the circuit described in test 401.1. Measure 108mV DC at A/ D_IN.

Bit pattern Register

87654321

—U106—

101v1101

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

87654321

—U109—

01101111

87654321

—U134—

1v01000v

—U130—

10011101

87654321

—U121—

01110000

ACDC_STB

MUX_STB

Troubleshooting 2-45

T est 401.3 — INVERT P A TH

Bank VAC Inputs Open Expected V alue <none speciﬁed> Limits <none speciﬁed> Fault Message <none>

Description This phase resets the circuit to a known state and turns the waveform sig-

nal off. Subsequent tests require that the A/D be in the normal operating mode.

Bit patterns

Bit pattern Register

87654321

—U106—

101v1101

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

87654321

—U109—

01101111

87654321

—U134—

1v01000v

—U130—

10011101

87654321 —U121— 01110000

ACDC_STB

MUX_STB

2-46 Troubleshooting

T est 402.1 — NON INV /10

Bank VAC Inputs Open Expected V alue <none speciﬁed> Limits <none speciﬁed> Fault Message <none>

Description This test places the ACV front end in the non-inverting conﬁguration.

Logic levels for this conﬁguration are as follows:

K102: /SETK1 low, /RESETK1 high

U103: Pins 8 and 9 low

U105: Pin 9 high

The signal path is from A CIN through K102 to the plus input of U102. Resistors R117 (9.9MÍ) and R146 (1.1MΩ) to form a ÷10 at the input. The feedback path for U102 is from the minus input through U103 (pins 6 and 7) to node ACFE.

The signal at A CFE is di vided by 10 through R110 to make A CFE/10. The ACFE/10 signal bypasses U112 through U105 (pin 8 set LO). The signal is then coupled across C115 to U118 which is conﬁgured for ×2 gain.

Bit patterns

Bit pattern Register

87654321

—U106—

110v0011

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

87654321

—U109—

11011111

87654321

—U134—

1v01000v

—U130—

10011101

87654321

—U121—

01110000

ACDC_STB

MUX_STB

Troubleshooting 2-47

T est 402.2 — NON INV /10

Bank VAC Inputs Open Expected V alue 0.108 volts Limits 0.02 volts Fault Message NON INV /10

Description The previous test sets up the circuit for this test. There is a routine in soft-

The signal path continues through Q101, Q102 and K101 to ACIN. The switched ACIN signal (coupled across C105) is applied to the circuit described in test 402.1 and the measurement is made.

Bit patterns

Bit pattern Register

87654321

—U106—

110v0011

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

87654321

—U109—

11011111

87654321

—U134—

1v01000v

—U130—

10011101

87654321 —U121— 01110000

ACDC_STB

MUX_STB

2-48 Troubleshooting

T est 402.3 — NON INV /10

Bank VAC Inputs Open Expected V alue <none speciﬁed> Limits <none speciﬁed> Fault Message <none>

Description This phase resets the circuit to a known state and turns the waveform sig-

Bit patterns

nal off. Subsequent tests require that the A/D be in the normal operating mode.

Bit pattern Register

87654321

—U106—

110v0011

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

87654321

—U109—

11011111

87654321

—U134—

1v01000v

—U130—

10011101

87654321

—U121—

01110000

ACDC_STB

MUX_STB

Troubleshooting 2-49

T est 403.1 — NON INV BEX2

Bank VAC Inputs Open Expected V alue <none speciﬁed> Limits <none speciﬁed> Fault Message <none>

Description This test places the ACV front end in the non-inverting conﬁguration.

Logic levels for this conﬁguration are as follows:

K102: /SETK1 low, /RESETK1 high

U103: Pins 8 and 9 low

U105: Pin 9 high

The signal path is from A CIN through K102 to the plus input of U102. Resistors R117 (9.9MΩ) and R146 (1.1MΩ) to form a ÷10 at the input. The feedback path for U102 is from the minus input through U103 (pins 6 and 7) to node A CFE. The A CFE signal bypasses U112 through U103 (pin 16 lo w). The signal is then coupled across C115 to U118 which is conﬁgured for x2 gain.

Bit patterns

Bit pattern Register

87654321

—U106—

011v0011

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

87654321

—U109—

11011111

87654321

—U134—

1v01000v

—U130—

10011101

87654321 —U121— 01110000

ACDC_STB

MUX_STB

2-50 Troubleshooting

T est 403.2 — NON INV BEX2

Bank VAC Inputs Open Expected V alue 1.08 volts Limits? 0.2 volts Fault Message NON INV BEX2

Description The previous test sets up the circuit for this test. There is a routine in soft-

The signal path continues through Q101, Q102 and K101 to ACIN. The switched ACIN signal (coupled across C105) is applied to the circuit described in test 403.1 and the measurement is made.

Bit patterns

Bit pattern Register

87654321

—U106—

011v0011

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

87654321

—U109—

11011111

87654321

—U134—

1v01000v

—U130—

10011101

87654321

—U121—

01110000

ACDC_STB

MUX_STB

Troubleshooting 2-51

T est 403.3 — NON INV BEX2

Bank VAC Inputs Open Expected V alue <none speciﬁed> Limits <none speciﬁed> Fault Message <none>

Description This phase resets the circuit to a known state and turns the waveform sig-

nal off. Subsequent tests require that the A/D be in the normal operating mode.

Bit patterns

Bit pattern Register

87654321

—U106—

011v0011

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

87654321

—U109—

11011111

87654321

—U134—

1v01000v

—U130—

10011101

87654321 —U121— 01110000

ACDC_STB

MUX_STB

2-52 Troubleshooting

TEST BANK: SENSE

T est 500.1 — 4W SENSE

Bank SENSE Inputs 4-wire short Expected V alue 0 volts Limits 0.0001 volts Fault Message SENSE LO

Description This test requires a 4-wire short at the input. The SLO node is the Sense

Bit patterns

LO jack on the front or rear panel. The 4-wire short connects SLO to LO. The 0V signal at SLO is routed through R132, R139, R148, R163, and Q121 to U126, which is conﬁgured as a unity gain buffer. The 0V output of U126 is routed to S7 of U163 where it is switched to the A/D MUX (×1 gain). Measure 0V at AD_IN.

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

00101111

87654321

—U134—

1v10000v

—U130—

01011101

87654321

—U121—

01110010

ACDC_STB

MUX_STB

Troubleshooting 2-53

T est 500.2 — 4W SENSE

Bank SENSE Inputs 4-wire short Expected V alue 0 volts Limits 0.0001 volts Fault Message SENSE HI

Description This test requires a 4-wire short at the input. The SHI node is the Sense HI

jack on the front or rear panel. The 4-wire short connects SHI to LO. The 0V signal at SHI is routed through R120, R124, R121, R125 and Q113 (4W control line high) to U113 BUFCOM. As in previous tests, this signal goes to the A/D MUX which is conﬁgured for ×1 gain. Measure 0V at AD_IN.

Bit patterns

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

00101111

87654321

—U134—

1v10000v

—U130—

10111101

87654321 —U121— 01101000

ACDC_STB

MUX_STB

2-54 Troubleshooting

TEST BANK: AMP/OHM

T est 600.1 — OHM/AMP

Bank AMP/OHM Inputs INPUT HI to AMPS Short Expected V alue 0.0095 volts Limits 0.001 volts Fault Message 1mA SOURCE

Description This test requires a jumper wire from the INPUT HI jack to the AMPS

jack on the front panel. The +7V reference is switched to the ohms circuit through U133. Q123 and Q125 are turned on to generate a 1mA current that is routed to the INPUT HI jack. The signal path for this 1mA current is from the +14V node through R194, Q125, Q119, Q120, K101 (pins 3 to 4) Q102, Q101, through the parallel combination of R115, L109, and R324, then to the INPUT HI jack.

The jumper wire then routes the 1mA into the AMPS jack through K103 (SETK3 control line high so that pins 3 to 4 and 7 to 8 are closed). This puts R205 in series with R158 for a total of 10.1Ω. The 1mA current through

10.1Ω generates around 10mV which is sensed through S101 and R142 to the AMPSHUNT node. The AMPSHUNT signal is routed to S6 of U163 where it is switched to the A/D MUX. The A/D MUX is conﬁgured for ×1 gain. Measure 10mV at AD_IN.

Bit patterns

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

00101111

87654321

—U134—

1v10111v

—U130—

11101101

87654321

—U121—

10110010

ACDC_STB

MUX_STB

Troubleshooting 2-55

T est 600.2 — OHM/AMP

Bank AMP/OHM Inputs INPUT HI to AMPS short Expected V alue 0.025 volts Limits 0.015 volts Fault Message .1 OHM SHUNT

Description This test requires a jumper wire from the INPUT HI jack to the AMPS

The jumper wire then routes the 1mA into the AMP jack and through

K103 (SETK3 control line low so that pins 2 to 3 and 8 to 9 are closed). This bypasses R205 and routes the 1mA through the 0.1Ω ohm resistor (R158). A 1mA current through 0.1Ω generates around 100µV which is sensed through S101 and R142 to the AMPSHUNT node.

Bit patterns

The AMPSHUNT signal is routed to S6 of U163 where it is switched to

the A/D MUX. The A/D MUX is conﬁgured for ×100 gain. Since this is a very small voltage, trace resistance and circuit offsets greatly affect the expected voltage of 10mV. This test is useful to detect the presence of the proper component operation and not so much their precision. Measure approximately 25mV at AD_IN.

Bit pattern Register

87654321

—U106—

110v1111

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

87654321

—U109—

00101111

87654321

—U134—

1v10011v

—U130—

11101011

87654321 —U121— 10110010

ACDC_STB

MUX_STB

2-56 Troubleshooting

T est 601.1 — AMP SHUNT

Bank AMP/OHM Inputs INPUT HI to AMPS short Expected V alue <none speciﬁed> Limits <none speciﬁed> Fault Message <none>

Description This test requires an external jumper wire be installed from the INPUT HI

jack to the AMPS jack on the front panel. There is a routine in software that generates a test signal current for the ACV AMP test. This signal generation is described in test 601.2.

The test signal is routed through the front end circuit to the front panel INPUT HI jack. The jumper connects the test signal to the front panel AMPS jack. The test signal is routed through K103 (pins 3 and 8 to pins 4 and 7. The signal current then ﬂows through the series combination of R205 (10Ω) and R158 (0.1Ω) to ground. This generates an AC voltage that is connected to AMPSHNT through S101 and R142.

The A CV front end is set up for the non-in verting conﬁguration as follows:

K102: /SETK1 low, /RESETK1 high

U103: Pins 8 and 9 low

U105: Pin 9 high

The AMPSHNT signal is routed through U105 (pin 16 lo w) to the plus input of U112 which is conﬁgured for ×10 gain. The output signal of the op amp is routed through U105 (pin 1 low) and coupled across C115 to U118 which is conﬁgured for ×2 gain.

The output of U118 goes to U110 the TRMS con verter through R129 and the parallel C113 and C114. U110 OUT pin 11 is feed through its own inter nal buffer pin 1 to 16 and the signal out is AC_MED. AC_MED signal is selected at U163 pin 6 to 8 and fed to A/D buffer U166 through Q117. The A/ D buffer is set up for ×1 gain through U129 pin 3 to 2 with / ×1 lo w. This test is the setup phase for the next test phase.

Bit patterns

Troubleshooting 2-57

Bit pattern Register

87654321

—U106—

110v0010

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

87654321

—U109—

11011111

87654321

—U134—

1v10110v

—U130—

10011101

87654321 —U121— 10110000

ACDC_STB

MUX_STB

2-58 Troubleshooting

T est 601.2 — AMP SHUNT

Bank AMP/OHM Inputs INPUT HI to AMPS Short Expected V alue 0.084 volts Limits 0.02 volts Fault Message AC AMP SHUNT

Description The previous test sets up the circuit for this test. There is a routine in soft-

ware that generates a waveform for the ACV tests. This is done by selecting the 7V reference by closing analog switch U133 (/7V controlline low). The reference is buffered by U123.

Control line OHMA line is high turning Q123 and Q125 on which generates a 1mA current source with R195, op amp U123, Q119, and associated circuitry. The /LOWOHM control line of U133 is switched to toggle Q120 on and off to generate the 1mA AC current to the OHM node.

This test current is then switched through K101 (pin 4 to 3). Control line /SETK2 is high and /RESETK2 is low. The test current goes through Q102, Q101, the parallel combination of R115, L109, and R324, then to the INPUT HI jack.

Bit patterns

The switched current signal is applied to the circuit described in the previous test and a measurement is made. The input signal switching stops while the A/D is taking the reading, then continues when the measurement is complete. There are delays before the reading is taken to ensure that the A CV section and ﬁlters have enough time to reach a charged stable reading. For this test, the switched signal can be traced through the circuit described in the previous test. Measure 84mV DC at A/D_IN.

Bit pattern Register

87654321

—U106—

101v0010

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

87654321

—U109—

11011111

87654321

—U134—

1v10110v

—U130—

10011101

87654321

—U121—

10110000

ACDC_STB

MUX_STB

Troubleshooting 2-59

T est 601.3 — AMP SHUNT

Bank AMP/OHM Inputs INPUT HI to AMPS Short Expected V alue <none speciﬁed> Limits <none speciﬁed> Fault Message <none>

Description This phase resets the circuit to a known state and turns the waveform sig-

nal off. Subsequent tests require that the A/D be in the normal operating mode.

Bit patterns

Bit pattern Register

87654321

—U106—

101v0010

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

87654321

—U109—

11011111

87654321

—U134—

1v10110v

—U130—

10011101

87654321 —U121— 10110000

ACDC23

MUX_STB

_STB

Disassembly

3-2 Disassembly

Introduction

This section explains how to handle, clean, and disassemble the Model 2000 Multimeter . This

section is organized as follows:

• Handling and cleaning — Describes how to properly handle, clean, and solder PC boards.

• Static sensitive devices — Explains how to handle ICs and CMOS devices.

• Assembly drawings — Provides mechanical drawings to assist in the disassembly and re-assembly of the Model 2000.

• Case cover removal — Provides the procedure for removing the case to gain access to the internal components.

• Motherboard removal — Provides the procedure for removing the motherboard.

• Front panel disassembly — Provides the procedure for removing the display board and front panel switch pad.

• Firmware replacement — Provides the procedure for removing and replacing the Model 2000 ﬁrmware.

• Removing power components — Explains how to remove the power transformer and power module.

• Instrument re-assembly — Provides general guidelines for re-assembling the Model

2000.

Disassembly 3-3

Handling and cleaning

T o avoid contaminating PC board traces with body oil or other foreign matter, avoid touching the PC board traces while you are repairing the instrument. Motherboard areas covered by the shield have high impedance devices or sensitive circuitry where contamination could cause degraded performance.

Handling PC boards

Observe the following precautions when handling PC boards:

• Wear cotton gloves.

• Only handle PC boards by the edges and shields.

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

• Do not touch areas adjacent to electrical contacts.

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

Solder repairs

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

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

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

• Once you have remov ed the ﬂux, only swab the repair area with methanol, then blo w dry the board with dry nitrogen gas.

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

3-4 Disassembly

Static sensitive devices

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

CAUTION Many CMOS devices are installed in the Model 2000. Handle all semicon-

ductor devices as static sensitive.

• Only transport and handle ICs in containers specially designed to prevent static b uild-up. T ypically, you receive these parts in anti-static containers made of plastic or foam. Keep these devices in their original containers until ready for installation.

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

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

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

• Only use anti-static type solder sucker.

• Only use grounded tip solder irons.

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

Assembly drawings

Use the following assembly drawings to assist you as you disassemble and re-assemble the Model 2000. Also, refer to these drawings for information about the Keithley part numbers of most mechanical parts in the unit. The drawings are located at the end of this section of the manual.

• Front Panel Assembly — 2000-040

• Chassis/Transformer Power Module Assembly — 2000-050

• Front Panel/Chassis Assembly — 2000-051

• Chassis Assembly — 2000-052

Disassembly 3-5

Case cover removal

If you need to troubleshoot the instrument or replace a component, you must gain access to

the components by removing the case.

WARNING Before removing the case cover, disconnect the line cord and any test leads from the instru-

ment.

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

2. Remove Mounting Ears — Remov e the screw that secures each mounting ear . Pull do wn and out on each mounting ear.

NOTE When re-installing the mounting ears, make sure to mount the right ear to the right

side of the chassis, and the left ear to the left side of the chassis. Eac h ear is marked “RIGHT” or “LEFT” on its inside surface.

3. Remove Rear Bezel — To remove the rear bezel, loosen the two captive screws that secure the rear bezel to the chassis. Pull the bezel away from the case.

4. Removing Grounding Screws — Remov e the two grounding scre ws that secure the case to the chassis. They are located on the bottom of the case at the back.

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

NOTE If you need to gain access to the components under the motherboard shield to trou-

bleshoot them, remove the shield. It is secured to the motherboard by a single screw.

3-6 Routine Maintenance

Changing trigger link lines

The Model 2000 uses two lines of the T rigger Link rear panel connector as External Trigger (EXT TRIG) input and Voltmeter Complete (VMC) output. At the factory, line 1 is conﬁgured as VMC and line 2 as EXT TRIG.

NOTE Line 1, 3 or 5 of the T rig g er Link can be conﬁ gured as VMC, while line 2, 4 or 6 can

be conﬁgured as EXT TRIG.

Trigger link line conﬁgurations are changed by moving the position of resistors inside the unit. Perform the following steps to change trigger link lines:

WARNING Make sure the instrument is disconnected from the power line and other equipment before

performing the following procedure.

Figure 3-1

Trigger link line connections

1. Remove the cover from the instrument as explained in “Case Cover Removal”. The resistors used to select the trigger link lines are located next to the T rigger Link con-

nector as shown in Figure 3-1. The “resistors” are actually solder beads that bridge pcboard pads. If the factory default lines are selected, the solder beads will be located at R270 (line 2, EXT TRIG) and R267 (line 1, VMC).

2. To change a trigger link line: A. Use a soldering iron and solder sucker to remove the appropriate solder bead.

B. Using a solder with OA-based ﬂux, apply a solder bead to the appropriate resistor

location.

3. Replace the cover on the instrument.

Mother Board

(View from top)

Trigger Link Lines

Line 1 = VMC (R267) Line 2 = EXT TRIG (R270) Line 3 = VMC (R266) Line 4 = EXT TRIG (R268) Line 5 = VMC (R265) Line 6 = EXT TRIG (R269)

Solder Bead

R270 R269 R268

R267 R265 R266

(Factory Default Configured)

Trigger

Link

Connector

Rear Panel

Motherboard removal

Perform the following steps to remove the motherboard. This procedure assumes that the case

cover is already removed.

1. Remove the IEEE-488 and RS-232 fasteners. The IEEE-488 and the RS-232 connectors each have two nuts that secure the connectors

to the rear panel. Remove these nuts.

2. Remove the front/rear switch rod. At the switch, place the edge of a ﬂat-blade screw driver in the notch on the pushrod.

Gently twist the screw driver while pulling the rod from the shaft.

3. Disconnect the front and rear input terminals. You must disconnect these input terminal connections for both the front and rear inputs:

• INPUT HI and LO

• SENSE HI and LO

• AMPS

Disassembly 3-7

Remove all the connections except the front AMPS connection by pulling the wires off the pin connectors. T o remov e the front panel AMPS input wire (white), ﬁrst remove the AMPS fuse holder, then use needle-nose pliers to grasp the AMP wire near fuse housing. Push the wire forward and down to snap the spring out of the fuse housing. Carefully pull the spring and contact tip out of housing.

During re-assembly, use the following table to identify input terminals:

Front wire color Rear wire color

INPUT HI INPUT LO SENSE HI SENSE LO AMPS

4. Unplug cables. C. Unplug the display board ribbon cable from connector J1014.

D. Unplug the transformer cables from connectors J1016 and J1015. E. Unplug the scanner board ribbon cable from connector J1017.

5. Remove the fastening scre w that secures the main PC board to the chassis. This screw is located along the left side of the unit towards the rear. It also holds down U144.

During re-assembly, replace the board, and start the IEEE-488 and RS-232 connector nuts and the mounting screw. T ighten all the f asteners once they are all in place and the board is correctly aligned.

Red Black Yellow Gray White

White/Red White/Black White/Yellow White/Gray —

6. Remove the motherboard, which is held in place by edge guides on each side, by sliding it forward until the board edges clear the guides. Carefully pull the motherboard from the chassis.

3-8 Disassembly

Front panel disassembly

Use the following procedures to remov e the display board and/or the pushbutton switch pad:

NOTE You must ﬁrst remove the case cover, the front/rear input switch, and the front input

terminal wires as described in earlier in this section.

1. Unplug the display board ribbon cable from connector J1014.

2. Remove the front panel assembly. This assembly has four retaining clips that snap onto the chassis over four pem nut studs.

Two retaining clips are located on each side of the front panel. Pull the retaining clips outward and, at the same time, pull the front panel assembly forward until it separates from the chassis.

3. Using a thin-bladed screw driv er , pry the plastic PC board stop (located at the bottom of the display board) until the bar separates from the casing. Pull the display board from the front panel.

4. Remove the switch pad by pulling it from the front panel.

Disassembly 3-9

Main CPU ﬁrmware replacement

Changing the ﬁrmware may be necessary as upgrades become available. The ﬁrmware revision level for the main CPU is displayed during the power-on sequence. The ﬁrmware for the main CPU is located in the EPROMs U156 (EVEN) and U157 (ODD), leadless ICs that resides in chip carriers on the PC board.

To replace the CPU ﬁrmware, do the following:

WARNING Disconnect the instrument from the power lines and remove the test leads before changing

the ﬁrmware.

1. Remove the case cover as described earlier in this section.

2. Locate U156 EVEN and U157 ODD (EPROMs) on the main PC board. The y are the only devices installed in chip carriers (sockets).

CAUTION EPROMs U156 and U157 are static sensitive devices. Be sure to follow the

handling precautions explained in the paragraph entitled “Static sensitive devices.”

3. Using an appropriate chip extractor, remove U156 and U157 from its chip carrier.

4. Position the new U156 EPROM on the appropriate chip carrier. Make sure the notched corner of the chip is aligned with the notch in the chip carrier.

5. With the EPROM properly positioned, push down on the chip until it completely seats into the chip carrier.

6. Repeat steps 4 and 5 for EPROM U157.

3-10 Disassembly

Removing power components

The following procedures to remove the po wer transformer and/or po wer module require that

the case cover and motherboard be removed, as previously explained.

Power transformer removal

Perform the following steps to remove the power transformer:

1. Remove motherboard.

2. Unplug the transformer wires that attach to the power module at the rear panel. During re-assembly, use drawing 2000-050 as a reference and replace the wires as fol-

lows:

Top wire Right top Right bottom Left top Left bottom

3. Remove the two nuts that secure the transformer to the bottom of the chassis.

4. Pull the black ground wire off the threaded stud and remove the po wer transformer from the chassis.

W ARNING To avoid electrical shock, which could result in injury or death, the black ground wire of the

transformer must be connected to chassis ground. When installing the power transformer, be sure to re-connect the black ground wire to the mounting stud on bottom of the chassis.

Gray Violet White Red Blue

Power module removal

Perform the following steps to remove the power module:

1. Remove motherboard.

2. Unplug the transformer wires that attach to the power module at the rear panel. During re-assembly, use drawing 2000-050 as a reference and replace the wires as fol-

lows:

Disassembly 3-11

Top wire Right top Right bottom Left top Left bottom

3. Disconnect the power module's ground wire. This green and yellow wire connects to a threaded stud on the chassis with a kep nut.

Gray Violet White Red Blue

4. Squeeze the latches on either side of the power module while pushing the module from the access hole.

W ARNING To avoid electrical shock, which could result in injury or death, the ground wire of the power

module must be connected to chassis ground. When installing the power module, be sure to re-connect the green and yellow ground wire to the threaded stud on the chassis.

3-12 Disassembly

Instrument re-assembly

Re-assemble the instrument by reversing the previous disassembly procedures. Make sure that all parts are properly seated and secured and that all connections are properly made. To ensure proper operation, replace and securely fasten the shield.

W ARNING T o ensure continued protection against electrical shock, verify that power line ground (green

and yellow wire attached to the power module) and the power transformer ground (black wire) are connected to the chassis.

Replaceable Parts

4-2 Replaceable Parts

Introduction

Parts list

This section contains replacement parts information and component layout drawings for the Model 2000.

The electrical parts lists for the Model 2000 are shown in Tables 4-1 to 4-3. For part numbers to the various mechanical parts and assemblies, use the Miscellaneous parts list and the assembly drawings provided at the end of Section 3.

Ordering information

To place an order, or to obtain information concerning replacement parts, contact your Keithley representative or the f actory (see inside front cover for addresses). When ordering parts, be sure to include the following information:

• Instrument model number (Model 2000)

• Instrument serial number

• Part description

• Component designation (if applicable)

• Keithley part number

Replaceable Parts 4-3

Factory service

If the instrument is to be returned to Keithley Instruments for repair, perform the following:

1. Call the Repair Department at 1-800-552-1115 for a Return Material Authorization (RMA) number.

2. Complete the service form at the back of this manual, and include it with the instrument.

3. Carefully pack the instrument in the original packing carton.

4. Write ATTENTION REP AIR DEPARTMENT and the RMA number on the shipping label.

Components layouts

The component layouts are provided in the following pages: Motherboard: 2000-250, pages 1 and 2

Connector board: 2000-250, pages 1 and 2 Display board: 2000-250, pages 3 and 4

4-4 Replaceable Parts

Table 4-1

Model 2000 connector board, parts list

Circuit desig. Description Keithley part no.

C101 J1034 P1017 R196

CAP, .1UF, 10%, 25V, CERAMIC (0805) CONN, MALE RT ANGLE, 32-PIN CABLE ASSEMBL Y RES, 2.21K, 1%, 100MW, THICK FILM (0805)

C-495-.1 CS-456 CA-123-14A R-418-2.21K

Table 4-2

Model 2000 display board, parts list

Circuit desig. Description Keithley part no.

C401,402,411 C403,404,405,407,409,410,412 C406,408 C413

CR401,402

DS401

P1014

R401,402,403,404,406,409,411 R405,408,410,412 R413 R417,418 R419 R420,421

RFI CLIP, CHASSIS TAPE, 3/4 WIDE X 1/32 THICK

CAP,.1UF, 20%,50V,CERAMIC(1206) CAP, .1UF, 10%, 25V, CERAMIC (0805) CAP, 33PF, 10%, 100V, CERAMIC (1206) CAP,22UF, 20%, 6.3,TANTALUM(C6032)

DIODE, MBR0520LT1(SOD-123)

DISPLAY

CABLE ASSEMBL Y

RES, 15k, 1%, 100MW, THICK FILM(0805) RES, 12.1, 1%, 125MW METAL FILM(1206) RES, 13K, 1%, 100MW, THICK FILM(0805) RES, 15k, 1%, 100MW, THICK FILM(0805) RES, 10M, 5%, 125MW, METAL FILM(1206) RES, 10K, 1%, 100MW, THICK FILM (0805)

2001-366-1A TP-12-1

C-418-.1 C-495-.1 C-451-33P C-417-22

RF-103

DD-52

CA-123-16A

R-418-15K R-391-12.1 R-418-13K R-418-15K R-375-10M R-418-10K

U401 U402,403

Y401

** Order present ﬁrmware revision.

PROGRAM IC, LATCHED DRIVERS,UCN-5812EPF-1(PLCC)

CRYSTAL, 4MHZ (SMT)

2000-800-** IC-732

CR-36-4M

Replaceable Parts 4-5

Table 4-3

Model 2000 motherboard, parts list

Circuit desig. Description Keithley part no.

AT101

C101,160,163,174,180,186,207 C102 C104 C105 C106 C107 C109 C112,248 C113,114,119,126,246,247 C115 C117,147,151,191,234,237 C120 C121,132,134,140 C123,245 C131,148 C135,203,198,183,187,197,249 C137 C145 C146 C153,111,225,122,118,155,116 C156 C157,179 C171,177 C175 C178,167,172,169,161,103,128 C194,182,199,200,136,233,232 C204-206,190,173,139,138,162 C209 C213,212,133,124,159,154,230 C221,168,185 C222 C224,141,158,150,176,219,220

CONTACT, FUSE CRIMP CONTACT ROUND HEAT SINK FOR U124 SOCKET PLCC-032-T-A FOR U156,157 SPRING, COMPRESSION 4-40X5/16 PHILLIPS PAN HD FOR IEEE CS TO BD

IC,DUAL HIGH CMR/SPEED OPTO,HCPL-2631

CAP, .1UF, 10%, 25V, CERAMIC (0805) CAP,.01UF,10%,1000V,CERAMIC CAP,100UF,20%,63V,ALUM ELEC CAP, .22UF, 20%, 400V FILM CAP, 15P, 1%, 100V CERAMIC (0805) CAP,.1UF, 20%,50V,CERAMIC(1206) CAP, 2.2UF, 20%, 63V, POLYCARB CAP, .01, 5%, 50V, NPO(1812) CAP, 1000P, 10%, 100V, CERAMIC (1206) CAP, .33UF, 20%, 63V, POLYCARBONATE CAP,.1UF, 20%,50V,CERAMIC(1206) CAP, 270PF, 5%, 100V, CERAMIC (0805) CAP, 220PF, 10%, 100V, CERAMIC (1206) CAP, 1000P, 10%, 100V, CERAMIC (1206) CAP, 1000UF, 20%, 50V ALUM ELEC CAP, .1UF, 10%, 25V, CERAMIC (0805) CAP, 33PF, 5%, 100V, CERAMIC (0805) CAP, 1000pF, 20%, 50V, CERAMIC (1206) CAP, 2200UF, 20%, 16V ALUM ELEC CAP, .1UF, 10%, 25V, CERAMIC (0805) CAP, 6800UF, -20+100%, 16V ALUMINUM CAP,100PF, 5%, 100V, CERAMIC(0805) CAP, 2200P, 10%, 100V CERAMIC CAP, 10UF,20%, 25V, TANTALUM (D7243) CAP, .1UF, 10%, 25V, CERAMIC (0805) CAP, .1UF, 10%, 25V, CERAMIC (0805) CAP, .1UF, 10%, 25V, CERAMIC (0805) CAP, 22UF, 20%, 25V, TANTALUM (D7243) CAP, .1UF, 10%, 25V, CERAMIC (0805) CAP, .1UF, 10%, 25V, CERAMIC (0805) CAP, 47P, 5%, 100V, CERAMIC (0805) CAP, 47P, 5%, 100V, CERAMIC (0805)

2001-314B CS-760 HS-41 SO-143-32 SP-5 4-40X5/16PPH

IC-588

C-495-.1 C-64-.01 C-403-100 C-513-.22 C-512-15P C-418-.1 C-480-2.2 C-514-.01 C-451-1000P C-482-.33 C-418-.1 C-465-270P C-451-220P C-451-1000P C-469-1000 C-495-.1 C-465-33P C-418-1000P C-473-2200 C-495-.1 C-313-6800 C-465-100P C-430-2200P C-440-10 C-495-.1 C-495-.1 C-495-.1 C-440-22 C-495-.1 C-495-.1 C-465-47P C-465-47P

4-6 Replaceable Parts

Table 4-3(cont.)

Model 2000 motherboard, parts list

Circuit desig. Description Keithley part no.

C241 C242,243 C244

CR102,103 CR104 CR105,108,114 CR106 CR110,CR118 CR111,112,115-117

E101,102

J1006 J1007 J1008 J1014 J1015 J1016 J1017

K102,101 K103

L101,103,102,104 L105,L106 L107,108 L109

CAP, .01UF, 10%, 50V CERAMIC(0805) CAP, .01UF, 10%, 50V CERAMIC(0805) CAP, 1000pF, 20%, 50V, CERAMIC (1206)

DIODE,BRIDGE,VM18 DIODE,SILICON,W04M (CASE WM) DIODE, SWITCHING, MMBD914 (SOT-23) DIODE, BRIDGE PE05 (CASE KBU) DIODE, DUAL HSM-2822T31(S0T-23) DIODE, DUAL SWITCHING, BAV99L(SOT-23)

SURGE ARRESTOR, CG3-1.5L

CONN, MICRODIN W/GND FINGERS CONN, RT ANGLE, MALE, 9 PIN CONN,RIGHT ANGLE,24 PIN CONN, HEADER STRAIGHT SOLDER PIN CONNECTOR, HEADER CONN, MALE, 5-PIN (MOLEX 42491) CONNECTOR, HEADER STRAIGHT SOLDER PIN

RELAY, MINATURE (DPDT) TQ2E-L2-5V RELAY, MINI SIGNAL REL

FERRITE CHIP 600 OHM BLM32A07(1206) FERRITE CHIP 600 OHM BLM32A07(1206) CHOKE CHOKE

C-491-.01 C-491-.01 C-418-1000P

RF-52 RF-46 RF-83 RF-48 RF-95 RF-82

SA-4

CS-792 CS-761-9 CS-501 CS-368-16 CS-784-4 CS-784-5 CS-368-14

RL-155 RL-163

CH-62 CH-62 CH-61 CH-63-22

LS101

Q101,102 Q103,110,112,115,118,128,130 Q104-109,113,114,117,120-126 Q119 Q116,111,129 Q127,131,132,133

R101,102 R103,107,108,113,120,121,124 R104,105 R106

BEEPER, 5V, 30MA, BRT1209P-06-C

TRANS, C-CHAN MOSFET, 2SK1412(TO-220ML) TRANS, NPN, MMBT3904 (SOT-23) TRANS, N CHANNEL JFET, SNJ132199(SOT-23) TRANS,P CHANNEL JFET,J270 (TO-92) TRANS, PNP, MMBT3906L(SOT-23) TRANS, N-MOSFET, VN0605T (SOT-23)

RES, 1M, 5%, 125MW, METAL FILM (1206) RES, 24K, 5%, 1W, 200V, THICK FILM 251 RES,549K, .1%,1/4W METAL FILM RES,11K,.1%,1/10W,METAL FILM

EM-5

TG-276 TG-238 TG-294 TG-166 TG-244 TG-243

R-375-1M R-437-24K R-315-549K R-263-11K

Replaceable Parts 4-7

Table 4-3(cont.)

Model 2000 motherboard, parts list

Circuit desig. Description Keithley part no.

R109 R110,133 R114 R115 R117 R122,134,272,181 R123 R127 R129 R135 R139,148,163 R142 R145,156,321,322 R146 R147 R149,151 R150 R152,143,137 R153 R154,230 R155 R157 R158 R159,166,185,275,307,314 R164,112 R168 R169,214,218 R172,167,160 R176,179,183,186,193,130,177 R178,184,187,161,213,257,248 R188 R189 R192 R194 R195 R196 R200,190,165,182,111,284,296 R201,204,223,229,231,233,206 R202,263,249,224,319 R205 R215 R216

RES, 1K, 1%, 125mW, METAL FILM (1206) RES NET, 9K-1K, MICRO DIVIDER RES, 604, 1%, 100MW THICK FILM(0805) RES, 5K, .1%, WIREWOUND RES NET, 100K, 9.9M, METAL FILM RES, 1K, 1%, 125mW, METAL FILM (1206) RES, 73.2K, 1%, 100MW, THICK FILM(0805) RES, 33.2K, 1%, 100MW, THICK FILM (0805) RES, 215, 1%, 100MW, THICK FILM (0805) RES, 33.2K, 1%, 100MW, THICK FILM (0805) RES, 24K, 5%, 1W, 200V, THICK FILM 2512 RES,10,5%,125MW,METAL FILM(1206) RES, 100, 1%, 100MW, THICK FILM (0805) RES, 1.1M, 5%, 125MW, METAL FILM (1206) RES, 732K,1%, 100MW, THICK FILM(0805) RES, 150, 1%, 100MW, THICK FILM(0805) RES, 25.5K, 1%, 100MW, THICK FILM (0805) RES,49.9K,1%,125MW, METAL FILM (1206) RES NET, 3.6K MICRO DIVIDER RES, 49.9K, 1%, 100MW THICK FILM(0805) RES, 4.99K, 1%, 100MW THICK FILM(0805) RES, 511, 1%, 100MW, THICK FILM (0805) RES, .1, 1%, 2W, 4-TERMINAL MOLDED RES, 475, 1%, 125mW, METAL FILM (1206) RES, 100K, 1%, 125mW, METAL FILM (1206) RES, 270,5%, 250mW, METAL FILM (1210) RES, 4.99K, 1%, 100MW THICK FILM(0805) RES, 1M, 1%, 100MW, THICK FILM(0805) RES, 100K, 1%, 100MW THICK FILM(0805) RES, 100, 1%, 100MW, THICK FILM (0805) RES, 49.9, 1%, 125mW, METAL FILM (1206) RES, 3.01K, 1%, 125MW, METAL FILM(1206) RES, 6.98K, 1%, 125MW, METAL FILM(1206) RESISTOR, METAL FILM RESISTOR, METAL FILM RES, 2.21K, 1%, 100MW, THICK FILM (0805) RES, 1K, 1%, 100MW, THICK FILM (0805) RES, 4.75K, 1%, 100MW, THICK FILM (0805) RES, 10K, 1%, 100MW, THICK FILM (0805) RES, 10, .5%, 1/8W, METAL FILM RES, 4.42K, 1%, 125MW METAL FILM(1206) RES, 2.21K, 1%, 125mW, METAL FILM (1206)

R-391-1K TF-246-2 R-418-604 R-249-5K TF-224 R-391-1K R-418-73.2K R-418-33.2K R-418-215 R-418-33.2K R-437-24K R-375-10 R-418-100 R-375-1.1M R-418-732K R-418-150 R-418-25.5K R-391-49.9K TF-246-1 R-418-49.9K R-418-4.99K R-418-511 R-342-.1 R-391-475 R-391-100K R-376-270 R-418-4.99K R-418-1M R-418-100K R-418-100 R-391-49.9 R-391-3.01K R-391-6.98K R-443-7.06K R-443-70.6K R-418-2.21K R-418-1K R-418-4.75K R-418-10K R-246-10 R-391-4.42K R-391-2.21K

4-8 Replaceable Parts

Table 4-3(cont.)

Model 2000 motherboard, parts list

Circuit desig. Description Keithley part no.

R220,221,264,212,217 R225 R226,228,235,237,250,252,255 R234 R238,244,254,293 R241 R243,259 R245 R246 R261 R267,270 R271 R273,274 R277 R279,140,256,299 R280,294 R283 R287 R288,289,290 R291,292 R295,118,175,276,282,316 R297,278,281 R300 R302,303 R304 R309 R310 R311 R312,313 R315 R317,320 R318 R324

RES, 2.21K, 1%, 100MW, THICK FILM (0805) RES, 470,5%, 125MW, METAL FILM(1206) RES, 475, 1%, 100MW, THICK FILM (0805) RES, 5.11K, 1%, 100MW, THICK FILM (0805) RES, 4.75K, 1%, 100MW, THICK FILM (0805) RES, 34K, 1%, 100MW, THICK FILM (0805) RES, 10, 10%, 100MW, THICK FILM(0805) RES, 475, 1%, 100MW, THICK FILM (0805) RES, 82.5, 1%, 100MW, THICK FILM (0805) RES, 200, 1%, 100MW, THICK FILM (0805) RES, .0499, 1%, 100MW, THICK FILM(0805) RES NET (SOIC) RES, 475, 1%, 125mW, METAL FILM (1206) RES, 66.5K, 1%, 100MW, THICK FILM(0805) RES, 1K, 1%, 100MW, THICK FILM (0805) RES, 49.9, 1%, 100MW THICK FILM(0805) RES, 470,5%, 125MW, METAL FILM(1206) RES, 1.28M, .1%, 1/8W METAL FILM RES, 1K, 1%, 100MW, THICK FILM (0805) RES, 47.5K, 1%, 100MW THICK FILM (0805) RES, 10K, 1%, 100MW, THICK FILM (0805) RES, 357, 1%, 100MW, THICK FILM (0805) RES, 2.15K, 1%, 125MW THIN FILM (1206) RES, 499, 1%, 100MW THICK FILM(0805) RES, 20K, 1%, 100MW THICK FILM (0805) RES,1K,.1%,1/10W,METAL FILM RES, 9.09K, .1%, 1/10W, METAL FILM RES, 392, 1%, 100MW, THICK FILM (0805) RES, 332K,1%, 100MW, THICK FILM (0805) RES, 100K, 1%, 100MW THICK FILM(0805) RES, 10, 10%, 100MW, THICK FILM(0805) RES, 73.2K, 1%, 100MW, THICK FILM(0805) RES, 2K, 1%, 125mW, METAL FILM (1206)

R-418-2.21K R-375-470 R-418-475 R-418-5.11K R-418-4.75K R-418-34K R-418-10 R-418-475 R-418-82.5 R-418-200 R-418-.0499 TF-245 R-391-475 R-418-66.5K R-418-1K R-418-49.9 R-375-470 R-176-1.28M R-418-1K R-418-47.5K R-418-10K R-418-357 R-423-2.15K R-418-499 R-418-20K R-263-1K R-263-9.09K R-418-392 R-418-332K R-418-100K R-418-10 R-418-73.2K R-391-2K

S101

TP102,103,104,105,106

U101 U102,118 U103,105,111,129 U104

SWITCH, PUSHBUTTON, 8 POLE

CONN,TEST POINT

INTEGRATED CIRCUIT IC, J-FET, OP-AMP, TLE2081CD(SOIC) IC,CMOS ANALOG SWITCH DG211DY(SOIC) IC, MOSFET DRIVER, TLP591B

SW-468

CS-553

IC-846 IC-967 IC-768 OC-877

Replaceable Parts 4-9

Table 4-3(cont.)

Model 2000 motherboard, parts list

Circuit desig. Description Keithley part no.

U106,109,121,130,134 U107,108 U110 U112 U113 U114 U116 U117,145 U119 U120,131,115 U123 U124 U125 U126 U133 U135 U136 U137,166 U138,132 U139 U141 U142 U144 U146 U147,164 U148,153 U149 U150 U151,152 U154 U155 U156 U157 U158 U159 U160 U161 U162 U163

IC, 8 STAGE SHIFT/STORE,MC14094BD(SOIC) IC, PHOTO, DARLINGTON TRANS, PS2506L-1 IC,TRMS TO DC CONVERTER, 637JR (SOLIC) IC, J-FET OP-AMP LF357M(SOIC) IC, OP-AMP, LTC1050CS8(SOIC) ICM DUAL J-FET OP-AMP, OP-282GS,(SOIC) IC, DARLINGTON ARRAY, ULN2003L (SOIC) IC, VOLT. COMPARATOR,LM311M (SOIC) IC,NEG VOLTAGE REG -15V,500MA,79M15 IC, QUAD COMPARATOR,LM339D (SOIC) IC, DUAL PICOAMP OP-AMP AD706JR (SOIC) IC,+5V REGULATOR,500mA,7805 IC,POS VOLTAGE REG +15V,500MA,7815 IC, OP-AMP, AD705JR(SOIC) IC, CMOS ANAL SWITCH, DG444DY, (SOIC) IC, 16BIT MICROPROCESSOR MC68306FC16 IC, SERIAL EPROM 24LC16B(SOIC) IC, HI-SPEED BIFET OP-AMP, AD711JR(SOIC) INTEGRATED CIRCUIT, OPA177GS(SOIC) IC, DUAL BIPOLAR OP-AMP, LT1124C58 IC, PRECISION REFERENCE, LM399 IC, OP-AMP, NE5534D (SOIC) IC, LOW DROPOUT REGULATOR, LM295T IC,POS NAND GATES/INVERT,74HCT14(SOIC) IC, DUAL D-TYPE F/F, 74HC74(SOIC) IC, QUAD 2 IN NOR, 74HCT02 (SOIC) IC, NCHAN LAT DMOS QUADFET,SD5400CY SOIC IC,OPTOCOUPLER,2611 IC,32KX8 STAT CMOS RAM,D43256C(SOMETRIC) IC, QUAD D FLIP FLOP W/CLK,RESET 74HC175 IC,OPTOCOUPLER,2601 PROGRAM PROGRAM IC, GPIB ADAPTER, 9914A (PLCC) IC +5V RS-232 TRANSCEIVER, MAX202(SOIC) IC,OCTAL INTER BUS TRANS,75161(SOLIC) IC,OCTAL INTERFACE BUS,75160(SOLIC) PROGRAM IC, 8-CHAN ANA MULTIPLEXER,DG408DY(SOIC)

IC-772 IC-911 IC-796 IC-966 IC-791 IC-968 IC-969 IC-776 IC-195 IC-774 IC-910 IC-93 IC-194 IC-814 IC-866 LSI-154 LSI-153 IC-894 IC-960 IC-955 196-600A IC-802 IC-962 IC-656 IC-773 IC-809 IC-893 IC-690 LSI-93-100 IC-923 IC-239 2000-804-** 2000-803-** LSI-123 IC-952 IC-647 IC-646 2000-802-** IC-844

4-10 Replaceable Parts

Table 4-3(cont.)

Model 2000 motherboard, parts list

Circuit desig. Description Keithley part no.

VR101,114 VR102 VR103,104 VR105,106,115,116 VR107,108 VR109 VR110 VR112,113

Y101 Y102

** Order present ﬁrmware revision.

VAR, 576V METAL OXIDE DIODE, ZENER 6.2V, BZX84B6V2 (SOT-23) DIODE, ZENER, 6.8V,MMSZ5235BT1 (SOD-23) DIODE, ZENER 11V,MMSZ11T1 (SOD-123) DIODE, ZENER 3.3V, MMBZ5226BL(SOT-23) DIODE, ZENER 17V, MMBZ5247BL (SOT-23) DIODE,ZENER 5.1V, BZX84C5V1 (SOT-23) DIODE, ZENER, 6.2V MMS26V2 SOD-123

CRYSTAL, 14.7456MHZ OSCILLATOR HIGH SPEED CMOS 12MHZ

VR-5 DZ-87 DZ-100 DZ-103 DZ-94 DZ-104 DZ-88 DZ-97

CR-39 CR-37

Table 4-4

Model 2000 mechanical, parts list

Description Keithley part no.

2-56X5/8 PHILLIPS PAN HEAD SCREW SCANNER BOARD ASSEMBLY 4-40X1/4 PHIL FLAT HD UNDERCUT SR WRAP TO CHASSIS 4-40X5/16 PHILLIPS PAN HD SEMS MOTHER BOARD TO CHASSIS 6-32 KEP NUT SAFETY GROUND 6-32X1 PH PAN HD SEMS SCR FOR MOTHER BOARD SHIELD 6-32X1/4 PHIL. PAN HD SEMS CARD GUIDE TO CHASSIS 6-32X1/4 PHILLIPS FLAT HD FOR REAR FOOT 8-32 SMALL NUT FOR TRANSFORMER MOUNTING #8 INTERNAL TOOTH LOCKWASHER FOR TRANSFORMER MOUNTING

2-56X5/8PPH 4-40X1/4PFHUC 4-40X5/16PPHSEM 6-32KEPNUT 6-32X1PPHSEM 6-32X1/4PPHSEM 6-32X1/4PFH 8-32SMNUT 8LKWA

Replaceable Parts 4-11

Table 4-4(cont.)

Model 2000 mechanical, parts list

Description Keithley part no.

BANANA JACK, PUSH-IN, BLACK BANANA JACK, PUSH-IN, RED BEZEL, REAR BRACKET, REAR PANEL SCANNER COVER PLATE CABLE CLAMP FOR DISPLAY CABLE & TR-299 WIRE CABLE CLAMP TIE WRAP, NYLON, 4" LONG FOR FRONT/REAR WIRES CAPTIVE PANEL SCREW FOR BEZEL CARD GUIDE/SHIELD CHASSIS ASSEMBL Y CONNECTOR, HARDWARE KIT FOR IEEE COVER DISPLAY LENS FASTENER FOR EARS FOOT FOOT, EXTRUDED FOOT,RUBBER FRONT PANEL OVERLAY FRONT PANEL PRINTED FRONT/REAR SWITCH ROD FUSE HOLDER FOR PM-1-1 FUSE, 3A, 250 FOR CURRENT INPUT JACK FUSE 0.25A FOR FH-35-1 JACK, CURRENT INPUT LINE MODULE LUG LUG MOTHERBOARD SHIELD MOUNTING EAR, LEFT MOUNTING EAR, RIGHT PC BOARD STOP PLASTIC PLUG FOR SCANNER COVER PLATE POWER ROD SCREWLOCK, FEMALE FOR RS-232 SWITCHPAD TRANSFORMER

BJ-13-0 BJ-13-2 428-303D 2001-328C CC-37 CC-38-2 FA-232-1C 2000-311A 2000-309D CS-713 2000-307C 2000-304A FA-230-2B 428-319A FE-22A FE-6 2000-303A 2000-318B 2001-322A FH-35-1 FU-99-1 FU-96-4 2001-312D PM-1-1B LU-130 LU-88 2000-306B 428-338B 428-328E 2001-371A FA-240 2001-320A CS-725 2000-310A TR-299B

4-12 Replaceable Parts

Table 4-5

Model 2000 miscellaneous, parts list

Description Keithley part no.

CALIBRATION MANUAL PACKAGE COVER PANEL, SCANNER DISK PROGRAMMING HANDLE LINE CORD QUICK REFERENCE GUIDE PACKAGE TEST LEADS USER'S MANUAL PACKAGE

2000-905-00 2001-372A 2000-DSK-81 428-329F CO-7 2000-903-00 CA-22 2000-900-00

Speciﬁcations

Index

AMPS fuse replacement 1-4 Analog signal switching states 2-13 Assembly drawings 3-4

Built-in Test documentation 2-22 Built-in Test overview 2-18

Case cover removal 3-5 Changing trigger link lines 3-6 Components layouts 4-3

Digital circuitry checks 2-12 Disassembly 3-1 Display board checks 2-11

Factory service 4-3 Front panel disassembly 3-8 Front panel tests 2-4

Handling and cleaning 3-3

Instrument re-assembly 3-12

Main CPU ﬁrmware replacement 3-9 Motherboard removal 3-7

Ordering information 4-2

Parts list 4-2 Power supply checks 2-11 Power-on test 2-3 Principles of operation 2-5

Removing power components 3-10 Repair considerations 2-3 Replaceable parts 4-1 Routine maintenance 1-1

Setting line voltage and replacing fuse 1-2 Speciﬁcations A-1 Static sensitive devices 3-4

Troubleshooting 2-1

❑

Service Form

Model No. _________________ Serial No. ______________________Date_________________ Name and T elephone No. ________________________________________________________ Company ______________________________________________________________________

List all control settings, describe problem and check boxes that apply to problem. _________________________

__________________________________________________________________________________________ __________________________________________________________________________________________

Intermittent

IEEE failure Front panel operational ❑ All ranges or functions are bad

Analog output follows display

Obvious problem on power-up

Particular range or function bad; specify

_______________________________

Batteries and fuses are OK Checked all cables

Display or output (check one)

Drifts Overload

Calibration only

(attach any additional sheets as necessary) Show a block diagram of your measurement including all instruments connected (whether power is turned on or

not). Also, describe signal source.

Where is the measurement being performed? (factory, controlled laboratory, out-of-doors, etc.)_______________

__________________________________________________________________________________________

What power line voltage is used?___________________ Ambient temperature? ________________________°F Relative humidity? ___________________________________________Other? ___________________________ Any additional information. (If special modiﬁcations have been made by the user, please describe.)

__________________________________________________________________________________________ __________________________________________________________________________________________

Be sure to include your name and phone number on this service form.

Unable to zero Will not read applied input

Certiﬁcate of calibration required

Unstable

Data required

Keithley Instruments, Inc.

28775 Aurora Road Cleveland, Ohio 44139

Printed in the U.S.A.

Keithley 2000rep schematic

Specifications and Main Features

Frequently Asked Questions

User Manual