Agilent 66312A Service Manual

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Service Manual

Agilent Model 66312A

Dynamic Measurement DC Source

and Agilent Model 6612B

System DC Power Supply

For instruments with Serial Numbers:

Agilent 66312A: US37442096 and up Agilent 6612B: US37470826 and up

5

Agilent Part No. 5962-0874 Printed in U.S.A. Microfiche No 6962-0875 September, 2000

Warranty Information

CERTIFICATION

Agilent Technologies certifies that this product met its published specifications at time of shipment from the factory. Agilent Technologies further certifies that its calibration measurements are traceable to the United States National Bureau of Standards, to the extent allowed by the Bureau's calibration facility, and to the calibration facilities of other International Standards Organization members.

WARRANTY

This Agilent Technologies hardware product is warranted against defects in material and workmanship for a period of three years from date of delivery. Agilent Technologies software and firmware products, which are designated by Agilent Technologies for use with a hardware product and when properly installed on that hardware product, are warranted not to fail to execute their programming instructions due to defects in material and workmanship for a period of 90 days from date of delivery. During the warranty period Agilent Technologies will, at its option, either repair or replace products which prove to be defective. Agilent Technologies does not warrant that the operation for the software firmware, or hardware shall be uninterrupted or error free.

For warranty service, with the exception of warranty options, this product must be returned to a service facility designated by Agilent Technologies. Customer shall prepay shipping charges by (and shall pay all duty and taxes) for products returned to Agilent Technologies. for warranty service. Except for products returned to Customer from another country, Agilent Technologies shall pay for return of products to Customer.

Warranty services outside the country of initial purchase are included in Agilent Technologies’ product price, only if Customer pays Agilent Technologies international prices (defined as destination local currency price, or U.S. or Geneva Export price).

If Agilent Technologies is unable, within a reasonable time to repair or replace any product to condition as warranted, the Customer shall be entitled to a refund of the purchase price upon return of the product to Agilent Technologies.

LIMITATION OF WARRANTY

The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by the Customer, Customer-supplied software or interfacing, unauthorized modification or misuse, operation outside of the environmental specifications for the product, or improper site preparation and maintenance. NO OTHER WARRANTY IS EXPRESSED OR IMPLIED. AGILENT TECHNOLOGIES. SPECIFICALLY DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

EXCLUSIVE REMEDIES

THE REMEDIES PROVIDED HEREIN ARE THE CUSTOMER'S SOLE AND EXCLUSIVE REMEDIES. AGILENT TECHNOLOGIES SHALL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WHETHER BASED ON CONTRACT, TORT, OR ANY OTHER LEGAL THEORY.

ASSISTANCE

The above statements apply only to the standard product warranty. Warranty options, extended support contacts, product maintenance agreements and customer assistance agreements are also available. Contact your nearest Agilent Technologies. Sales and Service office for further information on Agilent Technologies' full line of Support Programs.

Safety Summary

The following general safety precautions must be observed during all phases of operation of this instrument. Failure to compl with these precautions or with specific warnings elsewhere in this manual violates safety standards of design, manufacture, and intended use o requirements.

WARNING

Servicing instructions are for use by service-trained personnel. To avoid dangerous electrical shock, do not perform any servicing unless you are qualified to do so. Some procedures described in this manual are performed with power supplied to the instrument while its protective covers are removed. If contacted, the energy available at many points may result in personal injury.

BEFORE APPLYING POWER.

the instrument. Agilent Technologies, Inc. assumes no liability for the customer's failure to comply with these

Verify that the product is set to match the available line voltage, the correct line fuse is installed, and all safety precautions ( following warnings) are taken. In addition, note the instrument's external markings described under "Safety Symbols"

GROUND THE INSTRUMENT.

Before switching on the instrument, the protective earth terminal of the instrument must be connected to the protective conductor of the (mains) power cord. The mains plug shall be inserted only in an outlet socket that is provided with a protective earth contact. This protective action must not be negated by the use of an extension cord (power cable) that is without a protective conductor (grounding). Any interruption of the protective (grounding) conductor or disconnection of the protective earth terminal will cause a potential shock hazard that could result in personal injury.

FUSES

Only fuses with the required rated current, voltage, and specified type (normal blow, time delay, etc.) should be used. Do not use repaired fuses or short-circuited fuseholders. To do so could cause a shock or fire hazard.

KEEP AWAY FROM LIVE CIRCUITS.

Operating personnel must not remove instrument covers. Component replacement and internal adjustments must be made by qualified service personnel. Do not replace components with power cable connected. Under certain conditions, dangerous voltages may exist even with the power cable removed. To avoid injuries, always disconnect power, discharge circuits and remove external voltage sources before touching components.

DO NOT SERVICE OR ADJUST ALONE.

Do not attempt internal service or adjustment unless another person, capable of rendering first aid and resuscitation, is present. Any adjustment, maintenance, and repair of this instrument while it is opened and under voltage should be avoided as much as possible. When this is unavoidable, such adjustment, maintenance, and repair should be carried out only by a skilled person who is aware of the hazard involved.

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DO NOT SUBSTITUTE PARTS OR MODIFY INSTRUMENT.

Because of the danger of introducing additional hazards, do not install substitute parts or perform any unauthorized modification to the instrument. Return the instrument to an Agilent Technologies, Inc. Sales and Service Office for service and repair to ensure that safety features are maintained.

SAFETY SYMBOLS

Refer to the table on the following page

WARNING The WARNING sign denotes a hazard. It calls attention to a procedure, practice, or the like, which, if not

correctly performed or adhered to, could result in personal injury. Do not proceed beyond a WARNING sign until the indicated conditions are fully understood and met.

Caution The CAUTION sign denotes a hazard. It calls attention to an operating procedure, or the like, which, if not

correctly performed or adhered to, could result in damage to or destruction of part or all of the product. Do not proceed beyond a CAUTION sign until the indicated conditions are fully understood and met.

Safety Symbol Definitions

Symbol Description

Direct current

Alternating current

Both direct and alternating current

Three-phase alternating current

Earth (ground) terminal

Protective earth (ground) terminal

Frame or chassis terminal

Terminal is at earth potential (Used for measurement and control circuits designed to be operated with one terminal at earth potential.)

Terminal for Neutral conductor on permanently installed equipment

Terminal for Line conductor on permanently installed equipment

On (supply)

Off (supply)

Standby (supply) Units with this symbol are not completely disconnected from ac mains when this switch is off. To completely disconnect the unit from ac mains, either disconnect the power cord or have a qualified electrician install an external switch.

In position of a bi-stable push control

Out position of a bi-stable push control

Caution, risk of electric shock

Caution, hot surface

Caution (refer to accompanying documents)

Notice

The information contained in this document is subject to change without notice. Agilent Technologies makes no warranty of any kind with regard to this material, including but not limited to, the implied warranties of merchantability, and fitness for a particular purpose.

Agilent Technologies damages in connection with the furnishing, performance or use of this material.

This document contains proprietary information which is protected by copyright. All rights are reserved. No part of this document may be photocopied, reproduced, or translated into another language without the prior written consent of Agilent Technologies.

shall not be liable for errors contained herein or for incidental or consequential

Printing History

The edition and current revision of this manual are indicated below. Reprints of this manual containing minor corrections and updates may have the same printing date. Revised editions are identified by a new printing date. A revised edition incorporates all new or corrected material since the previous printing date.

Changes to the manual occurring between revisions are covered by change sheets shipped with the manual. In some cases, the manual change applies only to specific instruments. Instructions provided on the change sheet will indicate if a particular change applies only to certain instruments.

First Edition ............February, 1997

Second Edition ...... September, 2000

Instrument Identification

The power supply is identified by a unique serial number such as, US36310101. The items in this serial number are explained as follows:

US36310101

The first two letters indicate the country of manufacture. US = United States.

The next four digits are the year and week of manufacture or last significant design change. Add 1960 to the first two digits to determine the year. For example, 36=1996. The third and fourth digits specify the week of the year (31 = the thirty-first week).

The last four digits (0101) are a unique number assigned to each unit.

Warranty Information 2 Safety Summary 3 Notice 4 Printing History 5 Instrument Identification 5 Table of Contents 6

INTRODUCTION 9

Organization 9 Safety Considerations 9 Related Documents 9 Revisions 10

Manual Revisions 10 Firmware Revisions 10

Electrostatic Discharge 10

VERIFICATION AND PERFORMANCE TESTS 11

Introduction 11 Test Equipment Required 11 Measurement Techniques 12

Setup for Most Tests 12 Electronic Load 13 Current-Monitoring Resistor 13

Operation Verification Tests 13 Performance Tests 13

Programming 13

Constant Voltage (CV) Tests 14

CV Setup 14 Voltage Programming and Readback Accuracy 14 CV Load Effect 14 CV Source Effect 15 CV Noise (PARD) 15 Transient Recovery Time 16

Constant Current (CC) Tests 16

CC Setup 16 Current Programming and Readback Accuracy 16 Current Sink (CC-) Operation 17 CC Load and Line Regulation 17 CC Load Effect 18 CC Source Effect 18 CC Noise (PARD) 19

Performance Test Equipment Form 19 Performance Test Record Form 20

TROUBLESHOOTING 21

Introduction 21 Test Equipment Required 22 Overall Troubleshooting 22

Flow Charts 22

Specific Troubleshooting Procedures 33

Power-on Self-test Failures 36 CV/CC Status Annunciators Troubleshooting 37 Bias and Reference Supplies 37 J307 Voltage Measurements 38 Manual Fan Speed Control 39 Disabling Protection Features 39

Post-repair Calibration 40

Inhibit Calibration Switch 40 Calibration Password 40

Initialization 41 ROM Upgrade 41

Identifying the Firmware 41 Upgrade Procedure 41

Disassembly Procedures 42

List of Required Tools 42 Cover, Removal and Replacement 43 A2 Interface Board, Removal and Replacement 43 Front Panel Assembly, Removal and Replacement 43 A3 Front Panel Board, Removal and Replacement 44 A1 Main Control Board 44 T1 Power Transformer, Removal and Replacement 44 Line Voltage Wiring 44

PRINCIPLES OF OPERATION 47

Introduction 47 I/O Interface Signals 47 A3 Front Panel Circuits 48 A2 Interface Circuits 48

Primary Interface 48 Secondary Interface 48

A1 Main Board Circuits 50

Power Circuits 50 Control Circuits 52

REPLACEABLE PARTS LIST 55

Introduction 55

DIAGRAMS 65

Introduction 65

General Schematic Notes 65 Backdating 65

INDEX 73

Introduction

Organization

This manual contains information for troubleshooting and repairing to the component level the Agilent Model 66312A Dynamic Measurement DC Source and the Agilent Model 6612B System DC Power Supply. Hereafter both models will be referred to as the dc power supply.

This manual is organized as follows:

Chapter 1

Chapter 2

Chapter 3

Chapter 4

Chapter 5

Chapter 6

Organization

Performance tests

Troubleshooting procedures

Principles of operation on a block-diagram level

Replaceable parts

Diagrams

Safety Considerations

WARNING: Hazardous voltages exist within the dc power supply chassis.

This dc power supply; is a Safety Class I instrument, which means it has a protective earth terminal. This terminal must be connected to earth ground through a power source equipped with a 3-wire, ground receptacle. Refer to the "Safety Summary" page at the beginning of this manual for general safety information. Before operation or repair, check the dc power supply and review this manual for safety warnings and instructions. Safety warnings for specific procedures are located at appropriate places in the manual.

Revisions

Manual Revisions

This manual was written for dc power supplies that have the same manufacturing dates (the first four digits) as those listed on the title page and whose unique identification number (the last four digits) are equal to or higher than those listed in the title page.

NOTE: 1) If the first four digits of the serial number of your unit are higher than those shown in the title

page, your unit was made after the publication of this manual and may have hardware or firmware differences not covered in this manual. If they are significant to the operation and/or servicing of the dc power supply, those differences are documented in one or more Manual Change sheets included with this manual.

2) If the first four digits of the serial number of your unit are lower than those shown on the title page, your unit was made before the publication of this manual and can be different from that described here. Such differences are covered in the backdating section in Chapter 6.

Firmware Revisions

You can obtain the firmware revision number by either reading the integrated circuit label, or query the dc power supply using the GPIB *IDN?' query command (see Chapter 3, ROM Upgrade).

Electrostatic Discharge

CAUTION: The dc power supply has components that can be damaged by ESD (electrostatic discharge).

Failure to observe standard antistatic practices can result in serious degradation of performance, even when an actual failure does not occur.

When working on the dc power supply, observe all standard, antistatic work practices. These include, but are not limited to:

a Working at a static-free station such as a table covered with static-dissipative laminate or with a conductive

table mat (Agilent P/N 9300-0797, or equivalent).

a Using a conductive wrist strap, such as Agilent P/N 9300-0969 or 9300-0970.

a Grounding all metal equipment at the station to a single common ground.

a Connecting low-impedance test equipment to static-sensitive components only when those

components have power applied to them.

a Removing power from the dc power supply before removing or installing printed circuit boards.

Verification and Performance Tests

Introduction

This document contains test procedures to verify that the dc power supply is operating normally and is within published specifications. There are three types of tests as follows:

Built-in Self Tests

Operation Verification

Performance Tests

NOTE: The dc power supply must pass the built-in self-tests before calibration or any of the verification

or performance tests can be performed. If the supply fails any of the tests or if abnormal test results are obtained, refer to the troubleshooting procedures in Chapter 3. The troubleshooting procedures will determine if repair and/or calibration is required.

These tests, run automatically when the power supply is turned on, check most of the digital circuits and the programming and readback DACs.

These tests verify that the power supply is probably operating normally but do not check all of the specified operating parameters.

These tests check that the supply meets all of the operating specifications as listed in the Operating Manual.

Test Equipment Required

Table 2-1 lists the equipment required to perform the verification and performance tests. A test record sheet with specification limits and measurement uncertainties (when test using the recommended test equipment) may be found at the back of this section.

WARNING: SHOCK HAZARD. These tests should only be performed by qualified personnel. During the

performance of these tests, hazardous voltages may be present at the output of the supply.

Table 2-1. Test Equipment Required for Verification and Performance Tests

Type Specifications Recommended Model

Current Monitor Resistor

DC Power Supply Minimum 2.5 A output current rating Agilent 6632B

Digital Voltmeter Resolution: 10 nV @ 1V

Electronic Load 20 V, 5 A minimum, with transient capability Agilent 6060B or equivalent

GPIB Controller HP Series 300 or other controller with full

15 A (0.1 ohm) 0.04%, for power supplies up to 15 A output

Readout: 8 1/2 digits Accuracy: 20 ppm

GPIB capabilities

Guildline 9230/15

Agilent 3458A or equivalent

2 - Verification and Performance Tests

Resistor (substitute for electronic load if load is too noisy for CC PARD test)

1 ohm, 12 W (or 2 ohm adjustable) 1 k ohm, 5%, 3 W 9 ohm, 100 W or Rheostat, 10 ohm, 150 W

Oscilloscope Sensitivity: 1 mV

Ohmite D12K2R0 (2 ohm adjustable) Agilent p/n 0813-0001 Ohmite RLS10R (10 ohm adjustable) Ohmite 11F103

Agilent 54504A or equivalent Bandwidth Limit: 20 MHz Probe: 1:1 with RF tip

RMS Voltmeter True RMS

Agilent 3400B or equivalent Bandwidth: 20 MHz Sensitivity: 100 µV

Variable-Voltage Transformer

Adjustable to highest rated input voltage range. Power: 500 VA

Measurement Techniques

Test Setup

Most tests are performed at the rear terminals of the supply as shown in Figure 2-1a. Measure the dc voltage directly at the +S and -S terminals. If the Power Supply is equipped with a Local/Remote switch, set the switch to Remote and connect the output for remote sensing. Use adequate wire gauge for the load leads.

SENSE

Load

resistor

1 K

Local

Remote

Set to

Remote

DVM, Scope, or

RMS voltmeter

(for CV tests)

NOTE: Connector

is removable

-S

50VDC MAX TO

SENSE

Local

Remote

Set to

Remote

-S

50VDC MAX TO

Ammeter

DVM or

RMS voltmeter

(for CC tests)

Current

monitor

Electronic

Load

(see note)

Note: Use dc supply with same polarity

connectons for - CC tests.

Replace load with 9 ohm resistor

for CC noise test.

Ammeter

Figure 2-1. Test Setup

-S

50VDC MAX TO

External

DC supply

SENSE

Load

resistor

1 K

Local

Remote

Set to

Remote

Verification and Performance Tests - 2

Electronic Load

Many of the test procedures require the use of a variable load capable of dissipating the required power. If a variable resistor is used, switches should be used to either; connect, disconnect, or short the load resistor. For most tests, an electronic load can be used. The electronic load is considerably easier to use than load resistors, but it may not be fast enough to test transient recovery time and may be too noisy for the noise (PARD) tests.

Fixed load resistors may be used in place of a variable load, with minor changes to the test procedures. Also, if computer controlled test setups are used, the relatively slow (compared to computers and system voltmeters) settling times and slew rates of the power supply may have to be taken into account. "Wait" statements can be used in the test program if the test system is faster than the supply.

Current-Monitoring Resistor

To eliminate output-current measurement error caused by voltage drops in the leads and connections, connect the current monitoring resistor between the -OUT and the load as a four-terminal device. Connect the currentmonitoring leads inside the load-lead connections directly at the monitoring points on the resistor element.

Operation Verification Tests

To assure that the supply is operating properly, without testing all specified parameters, perform the following test procedures:

a. Perform the turn-on and checkout procedures given in the Operating Manual.

b. Perform the Voltage Programming and Readback Accuracy test, and the Current Programming and Readback

Accuracy tests from this procedure.

Performance Tests

NOTE: A full Performance Test consists of only those items listed as “Specifications” in Table A-1 of the

Operating Manual, and that have a procedure in this document.

The following paragraphs provide test procedures for verifying the supply's compliance with the specifications listed in Table A-1 of the Operating Manual. All of the performance test specifications and calculated measurement uncertainties are entered in the appropriate Performance Test Record Card for your specific model. You can record the actual measured values in the column provided in this card.

If you use equipment other than that recommended in Table 2-1, you must recalculate the measurement uncertainties for the actual equipment used.

Programming

You can program the supply from the front panel keyboard or from a GPIB controller when performing the tests. The test procedures are written assuming that you know how to program the supply either; remotely from a GPIB controller or locally using the control keys and indicators on the supply's front panel. Complete instructions on remote and local programming are given in the User’s Guide and in the Programming Guide.

2 - Verification and Performance Tests

Constant Voltage (CV) Tests

CV Setup

If more than one meter or if a meter and an oscilloscope are used, connect each to the terminals by a separate pair of leads to avoid mutual coupling effects. For constant voltage dc tests, connect only to +S and -S, since the unit regulates the output voltage that appears between +S and -S, and not between the (+) and (-) output terminals. Use coaxial cable or shielded two-wire cable to avoid noise pickup on the test leads.

Voltage Programming and Readback Accuracy

This test verifies that the voltage programming, GPIB readback and front panel display functions are within specifications. Note that the values read back over the GPIB should be identical to those displayed on the front panel.

a. Turn off the supply and connect a digital voltmeter between the +S and the -S terminals as shown in Figure 2-

1a.

b. Turn on the supply and program the supply to zero volts and the maximum programmable current with the load

off.

c. Record the output voltage readings on the digital voltmeter (DVM) and the front panel display. The readings

should be within the limits specified in the performance test record chart for the appropriate model under CV PROGRAMMING @ 0 VOLTS. Also, note that the CV annunciator is on. The output current reading should be approximately zero.

d. Program the output voltage to full-scale.

e. Record the output voltage readings on the DVM and the front panel display. The readings should be within the

limits specified in the performance test record chart for the appropriate model under CV PROGRAMMING @ FULL SCALE.

CV Load Effect

This test measures the change in output voltage resulting from a change in output current from full load to no load.

a. Turn off the supply and connect the output as shown in Figure 2-1a with the DVM connected between the +S

and -S terminals.

b. Turn on the supply and program the current to the maximum programmable value and the voltage to the full-

scale value.

c. Adjust the load for the full-scale current as indicated on the front panel display. The CV annunciator on the

front panel must be on. If it is not, adjust the load so that the output current drops slightly.

d. Record the output voltage reading on the DVM connected to +S and -S.

e. Open the load and again record the DVM voltage reading. The difference between the DVM readings in steps

(d) and (e) is the load effect voltage, and should not exceed the value listed in the performance test record chart for the appropriate model under CV LOAD EFFECT.

Verification and Performance Tests - 2

CV Source Effect

This test measures the change in output voltage that results from a change in ac line voltage from the minimum to maximum value within the line voltage specifications.

a. Turn off the supply and connect the ac power line through a variable voltage transformer.

b. Connect the output as shown in Figure 2-1a with the DVM connected between the +S and the -S terminals. Set

the transformer to nominal line voltage.

c. Turn on the supply and program the current to the maximum programmable value and the output voltage to the

full-scale value .

d. Adjust the load for the full-scale current value as indicated on the front panel display. The CV annunciator on

the front panel must be on. If it is not, adjust the load so that the output current drops slightly.

e. Adjust the transformer to the lowest rated line voltage (e.g., 104 Vac for a 115 Vac nominal line voltage input).

f. Record the output voltage reading on the DVM.

g. Adjust the transformer to the highest rated line voltage (e.g., 127 Vac for 115 Vac nominal line voltage input).

h. Record the output voltage reading on the DVM. The difference between the DVM reading is steps (f) and (h) is

the source effect voltage and should not exceed the value listed in the performance test record chart for the appropriate model under CV SOURCE EFFECT.

CV Noise (PARD)

Periodic and random deviations (PARD) in the output (ripple and noise) combine to produce a residual ac voltage superimposed on the dc output voltage. CV PARD is specified as the rms or peak-to-peak output voltage in the frequency range specified in the User’s Guide.

a. Turn off the supply and connect the output as shown in Figure 2-1a to an oscilloscope (ac coupled) between the

(+) and the (-) terminals. Set the oscilloscope's bandwidth limit to 20 MHz and use an RF tip on the oscilloscope probe.

b. Turn on the supply and program the current to the maximum programmable value and the output voltage to the

full-scale value.

c. Adjust the load for the full-scale current value as indicated on the front panel display.

d. Note that the waveform on the oscilloscope should not exceed the peak-to-peak limits in the performance test

record chart for the appropriate model under CV NOISE (PARD).

e. Disconnect the oscilloscope and connect an ac rms voltmeter in its place. The rms voltage reading should not

exceed the RMS limits in the performance test record chart for the appropriate model under CV NOISE (PARD).

2 - Verification and Performance Tests

Transient Recovery Time

This test measures the time for the output voltage to recover to within the specified value following a 50% change in the load current.

tttt

Unloading

Transient

Figure 2-2. Transient Waveform

a. Turn off the supply and connect the output as in Figure 2-1a with the oscilloscope across the +S and the -S

terminals.

b. Turn on the supply and program the output voltage to the full-scale value and the current to the maximum

programmable value.

c. Set the load to the Constant Current mode and program the load current to 1/2 the power supply full-scale rated

current.

d. Set the electronic load's transient generator frequency to 100 Hz and its duty cycle to 50%.

e. Program the load's transient current level to the supply's full-scale current value and turn the transient generator

on.

f. Adjust the oscilloscope for a waveform similar to that in Figure 2-2.

g. The output voltage should return to within the specified voltage (v) in less than the specified time (t). Check

both loading and unloading transients by triggering on the positive and negative slope.

Loading Transient

Constant Current (CC) Tests

CC Setup

Follow the general setup instructions in the Measurement Techniques paragraph and the specific instructions given in the following paragraphs.

Current Programming and Readback Accuracy

This test verifies that the current programming and readback are within specification.

a. Turn off the supply and connect the current monitoring resistor across the power supply output and the DVM

across the resistor. See "Current Monitoring Resistor" for connection information.

b. Turn on the supply and program the output voltage to 5 V and the current to 20mA (±1mA).

c. Divide the voltage drop (DVM reading) across the current monitoring resistor by its resistance to convert to

amps and record this value (Iout). Also, record the current reading on the front panel display. The readings should be within the limits specified in the performance test record card for the appropriate model under CC PROGRAMMING @ 0 AMPS.

d. Program the output current to full-scale .

Verification and Performance Tests - 2

e. Divide the voltage drop (DVM reading) across the current monitoring resistor by its resistance to convert to

amps and record this value (Iout). Also, record the current reading that appears on the front panel display. The readings should be within the limits specified in the performance test record card for the appropriate model under CC PROGRAMMING @ FULL-SCALE.

Current Sink (-CC) Operation

This test verifies current sink operation and readback.

a. Turn off the supply and connect the output as shown in Figure 2-1a, except connect a dc power supply in place

of the electronic load as indicated. Connect the DMM across the current shunt.

b. Set the external power supply to 5 V and a current value approximately 20% above the full scale current rating

of the supply under test.

c. Turn on the supply under test and program the output voltage to zero and full scale output current. The current

on the UUT display should be approximately −1.4 A.

d. Divide the voltage drop across the current monitoring resistor by its resistance to obtain the current sink value in

amps and subtract this from the current reading on the display. The difference between the readings should be within the limits specified in the performance test record chart under CURRENT SINK READBACK.

Low Range Current Readback Accuracy

This test verifies the readback accuracy of the 20 milliampere current range.

a. Turn off the supply and connect the output as shown in Figure 2-1b. Set the DMM to operate in current mode.

b. Turn on the supply under test, set the current range to LOW, and program the output voltage to zero and full

scale output current. The current on the UUT display should be approximately 0 mA.

c. Record the current reading on the DMM and the reading on the front panel display. The difference between the

two readings should be within the limits specified in the performance test record chart under 20mA RANGE CURRENT READBACK ACCURACY @ 0A.

d. Program the output voltage to 20V and record the current reading on the DMM and the reading on the front

panel display. The difference between the readings should be within the limits specified in the performance test record chart for the appropriate model under 20mA RANGE CURRENT READBACK ACCURACY @ 20mA

e. Turn off the supply and connect the output and an external supply as shown in Figure 2-1c. Set the DMM to

operate in current mode.

f. Turn on the external supply and program it to 20 V and 1 amp. Then program the supply under test to zero

volts and 1 amp. The UUT display should read approximately −20 mA.

c. Record the current reading on the DMM and the reading on the front panel display. The difference between the

two readings should be within the limits specified in the performance test record chart under 20mA RANGE CURRENT READBACK ACCURACY @ −20 mA.

CC Load and Line Regulation

These tests (CC Load Effect and CC Source Effect given below) are tests of the dc regulation of the power supply's output current. To insure that the values read are not the instantaneous measurement of the ac peaks of the output current ripple, several dc measurements should be made and the average of these readings calculated. An example of how to do this is given below using an Agilent 3458A System Voltmeter programmed from the front panel. Set up the voltmeter and execute the "Average Reading" program follows:

a. Program 10 power line cycles per sample by pressing NPLC 1 0 ENTER .

b. Program 100 samples per trigger by pressing (N Rdgs/Trig) 1 0 0 ENTER .

2 - Verification and Performance Tests

c. Set up voltmeter to take measurements in the statistical mode as follows:

Press Shift key, f0, Shift key, N. Press ^ (up arrow) until MATH function is selected, then press >. Press ^ (up arrow until STAT function is selected then press (ENTER).

d. Set up voltmeter to read the average of the measurements as follows:

Press Shift key, f1, Shift key, N. Press down arrow until RMATH function is selected, then press >. Press ^ (up arrow) until MEAN function is selected, then press ENTER.

e. Execute the program by pressing f0, ENTER, TRIG, ENTER.

f. Wait for 100 readings and then read the average measurement by pressing f1, ENTER.

To repeat the measurement, perform steps (e) and (f).

CC Load Effect

This test measures the change in output current for a change in load from full scale output voltage to short circuit.

a. Turn off the supply and connect the output as shown in Figure 2-1a with the DVM connected across the current

monitoring resistor.

b. Turn on the supply and program the current to the full scale current value and the output voltage to the

maximum programmable voltage value.

c. Adjust the load in the CV mode for full scale voltage as indicated on the front panel display. Check that the CC

annunciator of the UUT is on. If it is not, adjust the load so that the output voltage drops slightly.

d. Record the output current reading (DVM reading/current monitor resistance value in ohms). You may want to

use the average reading program described under “CC Load and Line Regulation”.

e. Short the load switch and record the output current reading. The difference in the current readings in steps (d)

and (e) is the load effect and should not exceed the limit specified in the performance test record chart for the appropriate model under CC LOAD EFFECT.

CC Source Effect

This test measures the change in output current that results when the AC line voltage changes from the minimum to the maximum value within the specifications.

a. Turn off the supply and connect the ac power line through a variable voltage transformer.

b. Connect the output terminals as shown in Figure 2-1a with the DVM connected across the current monitoring

resistor. Set the transformer to the nominal line voltage.

c. Turn on the supply and program the current to the full scale value and the output voltage to the maximum

programmable value.

d. Adjust the load in the CV mode for full scale voltage as indicated on the front panel display. Check that the CC

annunciator of the UUT is on. If it is not, adjust the load so that the output voltage drops slightly.

e. Adjust the transformer to the lowest rated line voltage.

f. Record the output current reading (DVM reading/current monitoring resistor in ohms). You may want to use

the average reading program described under “CC Load and Line Regulation”.

g. Adjust the transformer to the highest rated line voltage.

h. Record the output current reading again. The difference in the current readings in steps (f) and (h) is the CC

source effect and should not exceed the values listed in the performance test record card under CC SOURCE EFFECT.

Verification and Performance Tests - 2

CC Noise (PARD)

Periodic and random deviations (PARD) in the output combine to produce a residual ac current, as well, as an ac voltage superimposed on the dc output. Constant current (CC) PARD is specified as the rms output current in a frequency range 20 Hz to 20 Mhz with the supply in CC operation.

a. Turn off the supply and connect the load, monitoring resistor, and rms voltmeter as shown in Figure 2-1a. The

Current Monitoring resistor may have to be substituted by one with a higher resistance and power rating, such as a 1 ohm 5 W current shunt in series with a 9 ohm resistor, to get the RMS voltage drop high enough to measure with the RMS voltmeter. Leads should be as short as possible to reduce noise pick-up. An electronic load may contribute ripple to the measurement so if the RMS noise is above the specification a resistive load may have to be substituted for this test.

b. Check the test setup for noise with the supply turned off. Other equipment (e.g. computers, DVMs, etc.) may

affect the reading.

c. Turn on the supply and program the current to full scale and the output voltage to the maximum programmable

value.

d. The output current should be at the full scale rating with the CC annunciator on.

e. Divide the reading on the rms voltmeter by the monitor resistance to obtain rms current. It should not exceed the

values listed in the performance test record card under CC NOISE (RMS).

Performance Test Equipment Form

Test Facility:_________________________ Report Number ________________________

____________________________________ Date _________________________________

____________________________________ Customer _____________________________

____________________________________ Tested By ____________________________

Model ______________________________ Ambient Temperature (C) ________________

Serial No. ____________________________ Relative Humidity (%) ___________________

Options _____________________________ Nominal Line Frequency __________________

Firmware Revision ____________________

Special Notes:

Test Equipment Used:

Description Model No. Trace No. Cal. Due Date

AC Source

DC Voltmeter

RMS Voltmeter

Oscilloscope

Electronic Load

Current Shunt

_________________ _________________ _________________

2 - Verification and Performance Tests

Performance Test Record Form

Model _________________ Report No _______________ Date __________________

Test Description Minimum Specs. Results* Maximum

Specs.

Constant Voltage Tests

Voltage Programming and Readback

Low Voltage (0V) Programming

Front Panel Display Readback

High Voltage (Full Scale) Programming

Front Panel Display Readback

Load Effect

Source Effect

PARD (Ripple and Noise)

Peak-to-Peak

RMS

Transient Response

Voltage in 100 µs

Constant Current Tests

Current Programming and Readback

Low current (0A) Programming

Readback Accuracy @ Iout = 20 mA

High Current (Full Scale) Programming

Readback Accuracy @ Iout

Current Sink (@ -1.4A) Readback

20 mA Range Current Readback

Readback Accuracy @ 0 A

Readback Accuracy @ + 20 mA

Readback Accuracy @ − 20 mA

PARD (Current Ripple and Noise)

RMS 0 mA _________ + 1.0 mA

Load Effect

Source Effect

* Enter your test results in this column

− 10 mV

Vout − 3 mV

19.980 V

Vout − 9 mV

− 2.0 mV

− 0.5 mV

0 mV

0 mV _________ + 20 mV 3 mV

− 1.0 mA

Iout − 0.25 mA

1.998 A

Iout − 4.3 mA

Isink − 3.65 mA

− 2.5 µA

Iout − 22.5 µA

− 0.5 mA

_________

_________ + 2.0mV

_________ + 0.5 mV

_________

_________ Isink + 3.65 mA

_________

_________ + 0.5 mA

+ 10 mV

Vout + 3 mV

20.020 V

Vout + 9 mV

+ 3 mV

+ 0.5 mV

+ 1.0 mA

Iout + 0.25 mA

2.002 A

Iout + 4.3 mA

+ 2.5 µA

Iout + 22.5 µA

Measurement

Uncertainty

1.6 µV

335 µV

20 µV

872 µV

50 µV

15.2 µA

252 µA

200 µA

0.1 µA

1.7 µA

200 µA

1.6 µA

Troubleshooting

Introduction

WARNING: SHOCK HAZARD. Most of the troubleshooting procedures given in this chapter are

performed with power applied and protective covers removed. Such maintenance should be performed only by service trained personnel who are aware of the hazards (for example, fire and electrical shock).

CAUTION: This instrument uses components which can either be damaged or suffer serious

performance degradation as a result of ESD (electrostatic discharge). Observe the standard antistatic precautions to avoid damage to the components. An ESD summary is given in Chapter 1.

This chapter provides troubleshooting and repair information for the dc power supply. Before attempting to troubleshoot the dc power supply, first check that the problem is with the supply itself and not with an associated circuit. The verification tests in Chapter 2 enable you to isolate a problem to the dc power supply. Troubleshooting procedures are provided to isolate a problem to one of the circuit boards or a particular circuit. Figure 3-2 shows the location of the circuit boards and other major components of the unit. If a problem has been isolated to the A1 Control circuit board, additional troubleshooting procedures are available to isolate the problem to the defective component(s). Disassembly procedures are provided at the end of this chapter and should be referred to, as required, in order to gain access to and/or replace defective components.

If a component is defective, replace it and then conduct the verification test given in Chapter 2.

NOTE: Note that when certain components are replaced, the supply must be calibrated (see "Post

Repair Calibration" later in this chapter). If the A2 Interface Board is replaced, the supply must be initialized before it is calibrated. See "Initialization" later in this chapter.

Chapter 5 lists all of the replaceable parts for the power supplies. Chapter 6 contains schematics, test point measurements, and component location diagrams to aid you in troubleshooting the supply.

3 - Troubleshooting

Test Equipment Required

Table 3-1 lists the test equipment required to troubleshoot the power supply. Recommended models are listed.

Table 3-1. Test Equipment Required for Troubleshooting

Type Purpose Recommended Model

GPIB Controller To communicate with the supply via the

GPIB interface

Digital Voltmeter To check various voltage levels Agilent 3458A

Oscilloscope To check waveforms and signal levels Agilent 54504A/54111A

Electronic Load To test operation of current circuit Agilent 6060B

IC Test Clips To access IC pins AP Products No. LTC

Ammeter/Current Shunt

To measure output current Guildline 9230/15

HP Series 300

Overall Troubleshooting

Overall troubleshooting procedures for the power supply are given in the Figure 3-1. The procedures first check that neither an AC input, nor a bias supply failure is causing the problem and that the supply passes the turn-on self test (error annunciator stays off). The normal turn-on, self-test indications are described in the "Checkout Procedure" in Chapter 3 of the User's Guide.

If the supply passes the self test and there are no obvious faults, you should perform the verification procedures in Chapter 2 from the front panel to determine if any functions are not calibrated or are not operating properly. Then program and read back a voltage via the GPIB to see if the supply responds properly to bus commands. If the supply fails any of the tests, you will be directed to the applicable flow chart or troubleshooting procedure.

Flow Charts

Troubleshooting flow charts are given in Figure 3-1 sheets 1-13. Several flow charts make reference to the test points listed in Chapter 6. The circuit locations of the test points are shown on the schematics and on the component location diagrams in Chapter 6.

Disconnect power, and

all loads then remove

cover. Set sense

switch to local,

reconnect power and

turn unit on.

Is Display on? Is Fan on?

Yes

Troubleshooting - 3

1. Check ac input and line cord.

2. Check line fuse.

3. Check line voltage selection,

see Fig. 3-3.

4. Check ac and bias voltages, see Table 3-3.

Yes

Is Fan on?

Yes

Error Message

displayed?

Go To "No Display",

Sheet 5, "A"

24V @ Q305-2

Check fan and Fan

Driver circuit

See Self Test Error

Yes

Codes, Table 3-2

Yes

Check +15V Unreg

bias circuit

Program full scale

voltage and current

and enable output.

Check the output

voltage with a DMM.

Go to sheet 2

Figure 3-1 Sheet 1. Main Flowchart

3 - Troubleshooting

From Sheet 1

Protect

Annunciator on?

Yes

Press "Protect" Key

displayed

Yes

R369 (FUSE)

2-4.5V?

Replace A2 Interface

board

RT301

Yes

(HS_TERM), 2.5V

Disable OCP, Reset

Yes

Protect and go to top of

Yes

page

Check F309, VR305,

R369, R414 and R454

Check RT301 and

R326

Output

voltage and

readback within

spec?

Yes

Go to Sheet 3

displayed

Yes

RI (remote inhibit)

displayed, replace A2

Interface board

Go to "Voltage

Troubleshooting" Sheet 6, "B"

Figure 3-1 Sheet 2. Main Flowchart

Go to "OV @ Turn On",

Sheet 9, "E"

Troubleshooting - 3

Figure 3-1 Sheet 3. Main Flowchart

3 - Troubleshooting

Program the supply up and

From Sheet 3

down to check the down

programming speed.

Down

programming

OK?

Yes

Check RI/DFI port (see

User's Guide)

RI/DFI OK?

Yes

No problems found

with basic operation.

Perform Verification

and Performance tests

to determine if a

problem exists.

Go to "Slow Downprogrammer"

Replace A2 Interface

Sheet 12, "H"

board

Figure 3-1 Sheet 4. Main Flowchart

"A" From Sheet 1

Measure 5Vp A2 J206,

(Red to Black) and 5Vp

Unreg (White to Black)

Troubleshooting - 3

5V biases OK?

Yes

Check 5V @ A2J211

Pin 1 to 8

5V OK?

Yes

Check for 5V pulses at

A2J211 Pins 4 (Tx)

and 5 (Rx) to primary

ground.

Tx Pulses OK?

Check A1, +5V

Interface Bias Supply

Replace A2 Interface

board

Yes

Rx Pulses OK?

Yes

Replace Front Panel/

Display board

Figure 3-1 Sheet 5. No Display

3 - Troubleshooting

"B" From Sheet 2

CC Annunciator

ON?

Unreg Annunciator

Output and display

close to prog value

CV_PROG @ R322 should

be 0 to -4.8 volts for 0 to

full scale programmed

voltage and VMON @

U322-7 should be 0 to 4.7

volts for 0 to full scale

output voltage

Yes

Go to "Current

Troubleshooting" Sheet 7, "C"

Go to "No Output",

Sheet 8, "D"

Calibrate Voltage

Replace A2 Interface

CV_PROG OK?

Yes

VMON OK?

Yes

Troubleshoot U322B

board

circuit

If output is OK and readback is

not, replace A2 Interface board.

If the display equals the output,

troubleshoot U322A circuit

Figure 3-1 Sheet 6. Voltage Troubleshooting

"C" From Sheet 3 or 6

Troubleshooting - 3

Unreg Annunciator

Yes

Output and display close to prog value

Yes

CC_PROG @ R336 is 0 to -4.8V

for 0 to full scale programmed

current, IMON_H @ U318A-7 is 0

to -4.8 volts for 0 to full scale output

current and IMON_L @ U319A-6 is

0 to -4.8 volts for 0 to 20mA output current in the low current readback

range.

CC_PROG OK?

Go to "Output Current

Unregulated" Sheet 13, "I"

Calibrate Current

Replace A2 Interface

board

Yes

IMON_H OK?

Yes

IMON_L OK?

Yes

If output is OK and readback is

not, replace A2 Interface board.

If the display equals the output,

troubleshoot U324A/B circuit

circuits.

Figure 3-1 Sheet 7. Current Troubleshooting

Troubleshoot R431

and U319A circuit

OK below about

12mA but not

Check Q302 circuit

above?

Yes

Check U319A circuit

3 - Troubleshooting

"D" From Sheet 6

Gated (G)+/-15V

@ F302 & F304

OK?

Yes

U321-5 > +15mV

Yes

Voltage @ U321-

7=U321-5

Yes

PM_INHIBIT @

R390 high

Replace A2 Interface

Check R360 and

U326B circuit

Check U321 circuit

Yes

board

Check U311/U312

circuits

Check output series

regulator and

downprogrammer

stages U308, U309,

Q303, Q306 through

Q310 and F309

Figure 3-1 Sheet 8. No Output

"E" From Sheet 2

Connect DC coupled

scope across the

output terminals and

turn on the supply while

observing the scope.

Troubleshooting - 3

Output

momentarily goes

high

Disable the OV

protection by sending

the command

"DIAG:SCR 0"

Unit still OVs?

U327-7 Low

(OV_DETECT*)

Go to "Output Held High",

Yes

Sheet 10,"F"

Replace A2 Interface

Board

Replace A2 Interface

board

Yes

Check that OV is

programmed to

maximum or replace

OV_PROG = +4V?

A2 Interface board

Yes

Check U327 circuit

Figure 3-1 Sheet 9. Overvoltage at Turn-On

3 - Troubleshooting

"F" From Sheet 9

Disable the OV

protection by sending

the command

"DIAG:SCR 0"

Disabled

annunciator on?

CV annunciator

on?

Yes

Gated +/-15 Biases

at zero?

Yes

Check Series

Regulator circuits,

U309, Q303, Q308 etc.

Voltmeter reads

+OL?

Yes

Check U316A (gain of

-1) and U322A circuits

No Yes

PM_INHIBIT @

R380 15V

Replace A2 Interface board and go back to

beginning. Probable

2nd problem.

Check Vmon amplifier,

U322B (Vmon = 0 to

4.7V for 0 to full scale output voltage)

Check U311/U312

Gated Bias circuits

"CONTROL"

U321B-7

< 0V ?

Yes

Check Series

Regulator circuits,

U309, Q303, Q308 etc.

Check U321B circuit

Figure 3-1 Sheet 10. Output Held High

"G" From Sheet 3

Program the output

voltage and current to

the full scale value and

the OV to 1/2.

Troubleshooting - 3

OV_Prog @

A1R321 =2V

Yes

A1 U327-3 0V

Yes

A1U327-2 Neg.

Yes

A1U327-7,

OV_DETECT*,

Low?

A2 Interface Board or

cable W8 defective

Check A1R382, R401,

Imon_comp (0V) and

Check A1R321, R387,

R391, R405, C349,

C317 and U327

Check A1U327

U327

Reset the OV and observe the OV_SCR* signal. Each time OV is

reset (Shift, Prot Clr) the unit will generate another OV. The OV

pulse (OV_SCR*) is

5us long.

Yes

A1R378,

OV_SCR* pulse

low 5us?

Yes

Check A1R301, C353,

U302A, R378 and A2

Interface Board

A1Q301 emitter

pulses high 5us?

Yes

Check A1CR301

Figure 3-1 Sheet 11. Unit Did Not Overvoltage

Check Q301, U302A

and all associated

resistors and

capacitors

3 - Troubleshooting

"H" From Sheet 4

Connect an external power

supply across the output (+ to

+, - to -). Program the UUT

voltage to 0V, Output ON and

the test supply to 5V and 2A

Meter indicates 5V,

-1.5A ?

U321A-1 -0.4V

Yes

U308A-1 -1.5V

Yes

Check Q306, Q309,

R436 and -Rail

Yes

Unit operating normally

Check U321A, D327,

R324 and R362

Check U308A, Q306,

D319 and associated

circuits

Figure 3-1 Sheet 12. Slow Downprogrammer

"I" From Sheet 7

Troubleshooting - 3

Output current less

than rating

CC_Prog @ R336

>-4.8V

Yes No

U326B-6 = 0.6V

Yes

U308A-3 > -0.5V

Yes

Check for 1 of Q303 or

Q310 stages not

conducting

Yes

Replace A2 Interface

board

Control (F307) =

U326B-6

Yes

Check output and downprogrammer

stages Q307-Q309

Check U321A circuit

Check R360, U321B

Check the following: Imon_P, U325A-6=0V Imon_H, U318A-6=>3.5V

Voltages OK

Yes

Check U324A/B

Note, U324A has a

gain of -1

Check associated

circuit

Figure 3-1 Sheet 13. Current at Maximum

3 - Troubleshooting

Specific Troubleshooting Procedures

Power-on Self-test Failures

The power-on self-test sequence tests most of the digital and DAC circuits. If the supply fails self-test, the display "ERR" annunciator will come on. You can then query the unit to find out what the error(s) are. When an error is detected, the output is not disabled so you can still attempt to program the supply to help troubleshoot the unit. Table 3-2 lists the self test errors and gives the probable cause for each error.

NOTE: A partial self test is performed when the *TST? query is executed. Those tests that

interfere with normal interface operation or cause the output to change are not performed by *TST?. The return value of *TST? will be zero if all tests pass, or the error code of the first test that failed. The power supply will continue normal operation if *TST? returns a non-zero value.

Table 3-2. Self-Test Error Codes/Messages

Error Code Description Probable Cause

E1 Checksum in Read-only Non-volatile ROM A2 Interface Bd

E2 Checksum in Config Non-volatile ROM A2 Interface Bd

E3 Checksum in Cal Non-volatile ROM A2 Interface Bd

E4 Checksum in State Non-volatile ROM A2 Interface Bd

E5 Checksum in RST Non-volatile ROM A2 Interface Bd

E10 RAM test failed A2 Interface Bd

E11 12 bit DAC test failed, 0 is written to DAC U241A and

B, ADC U242 is checked for 133 +/- 7 counts

E12 12 bit DAC test failed, 4095 is written to DAC U241A

and 0 to B, ADC U242 is checked for 71 +/- 7 counts

E13 12 bit DAC test failed, 0 is written to DAC U241A and

4095 to B, ADC U242 is checked for 71 +/- 7 counts

E14 12 bit DAC test failed, 4095 is written to DAC U241A

and B, ADC U242 is checked for 10 +/- 7 counts

E15 8 bit DAC test failed, 10 and 240 are written to DAC

U244, ADC U242 is checked for 10 and 240 +/- 7 counts

E80 Dig I/O test failed, SEC_PCLR written low and high,

read back through Xilinx

E213 RS-232 input buffer overrun A2 Interface Bd

E216 RS-232 framing error A2 Interface Bd

E217 RS-232 parity error A2 Interface Bd

E218 RS-232 UART input overrun A2 Interface Bd

E220 Front Panel comm UART input overrun A3 Front Panel/Display Bd

E221 Front Panel comm UART framing error A3 Front Panel/Display Bd

E222 Front Panel comm UART parity error A3 Front Panel/Display Bd

E223 Front Panel firmware input buffer overrun A3 Front Panel/Display Bd

A2 Interface Bd

Troubleshooting - 3

CV/CC Status Annunciators Troubleshooting

The CV/CC annunciators are particularly helpful when troubleshooting a unit with no output. If the unit has no output voltage or current and one of the annunciators is on then the problem is in the control circuit associated with that annunciator. An example of how this might be useful would be in a case where the voltage and current are programmed to some positive value, there is no output voltage and the CV annunciator is on. This indicates that the problem is probably in the Voltage Amplifier circuit. If the CC annunciator were on then the problem would likely be in the Current Amplifier. If UNR is indicated then neither the voltage nor the current circuits are in control and the problem would be in circuits after the gating diodes such as the driver or output regulator stages.

When troubleshooting the CV/CC status annunciators or the status readback circuits, first measure the voltage drop across the gating diodes; A1 D317 (CV) and D321 (CC). A conducting diode indicates an active (ON) control circuit. This forward drop is applied to the input of the associated status comparator (U328C and D respectively) and drives the output (CV_DETECT* or CC_DETECT*) low. The low signal indicates an active status which is sent to the A2 board microprocessor. The front panel CV annunciator indicates when the CV mode is active (CV_DETECT* is low). The front panel CC annunciator indicates when the CC mode is active (CC_DETECT* is low). The UNREGULATED (UNR) annunciator comes on when neither the CV nor CC is active.

Bias and Reference Supplies

Before troubleshooting any circuit check the bias and/or reference voltages to make sure that they are not the cause. Table 3-3 lists the bias and reference voltage test points for the A1 Main Control , A2 Interface, and the A3 Front Panel/Display boards. Unless otherwise noted, all voltages are measured with respect to secondary common (R431) with no load on the supply.

Table 3-3. Bias and Reference Voltages

Bias Test Point Common Measurement

+5V primary A1 J206-1(Red) Chassis (J206-2 black) +5V +/- 0.15V

+5V secondary A1 R423 Secondary Common +5V +/- 0.2V

+15V secondary A1 R419 Secondary Common +15V +/- 0.6V

-15V secondary A1 R422 Secondary Common -15V +/- 0.6V

+15V secondary gated A1 F304 Secondary Common +14.2V +/- 5%

-15V secondary gated A1 F302 Secondary Common -14.2V +/- 5%

+Rail

-Rail

+2.5V reference

Measured with respect to - Output at nominal ac input line voltage

the 2.5V reference originates on the A2 Interface board

A1 D311 cathode - Output +32V +/- 10% (100mV P/P)

A1 D307 Anode Secondary Common -6.5V +/- 10% (100mV P/P)

A1 J307-6 Secondary Common +2.5V +/- 5%

3 - Troubleshooting

J307 Voltage Measurements

J307 connects the A1 Main Board Assembly to the A2 Interface Assembly. Table 3-4 provides a quick method of determining if the voltages between these assemblies are within the normal range. If any of these voltages is outside the normal range, refer to the flowcharts to further troubleshoot the circuit associated with the abnormal voltage.

Table 3-4. Voltage Measurements at J307 (A2 Interface to A1 Main board)

A1J307

Pin #

1 PM_INHIBIT (Enabled) 0 0

2 OV_SCR* +5 +5

3 OV_PROG +3.9 +3.9

4 FAN_PROG +2.8 +3.8

5 OV_DETECT* +5 +5

6 SW_POS (Norm) +5 +5

7 RANGE_SELECT (High) 0 0

8 OS_TRIM_NEG (COMP) +1.7 +1.7

OS_TRIM_NEG (SCPI) +4.0 +4.0

9+5Vs +5 +5

10 COMMON 0 0

11 COMMON 0 0

12 +15Vs +15 +15

13 -15Vs -15 -15

14 HS_THERM (@25C) +2.5 +2.5

15 FUSE +2.4 +2.6

16 IMON_H 0 +3.5

17 IMON_L

IMON_L (@20mA Out)

18 IMON_P 0 0

19 VMON +4.8 +4.8

20 COMMON 0 0

21 COMMON 0 0

22 COMMON 0 0

23 COMMON 0 0

24 CV_PROG -4.8 -4.8

25 CC_PROG -4.8 -4.8

26 CC_DETECT* +5 0

27 CCN_DETECT* +5 +5

28 CV_DETECT* 0 +5

Signal Name CV Mode

Full Scale Voltage

No Load

+4.8

CC Mode

Full Scale Voltage

Full Load

+14.7

+4.8

Troubleshooting - 3

Manual Fan Speed Control

Under some circumstances such as testing acoustical devices where the fan noise would interfere with the test, it would be advantageous to reduce the fan speed. If the test requires a very light load, the ambient temperature is low and the duration of the test is short, the fan speed may be temporarily reduced. The turnon default is "Automatic" so this procedure must be performed, as needed, every time the line voltage is turned on. To manually control the fan speed:

a. Simultaneously depress the "0" and "1" keys. EEINIT <model> will be displayed.

b. Using the Up/Down annunciator keys select FAN:MODE<AUTO>.

c. Using the Up/Down arrows select FAN:MODE <MAN>.

d. Press "Enter".

e. Simultaneously depress the "0" and "1" keys. EEINIT <model> will be displayed.

f. Using the Up/Down annunciator keys select FAN:SPEED <data>.

g. Press "Enter Number".

h. Enter the desired speed (numeric entry range is 0 to 100%).

i. Press "Enter".

Disabling Protection Features

Except for overvoltage protection, the power supply's protection features may be disabled. This is not recommended as a normal operating condition but is helpful under some circumstances such as troubleshooting. The turn-on default is "NO-PROTECT OFF" (protection enabled) so this procedure must be performed, as needed, every time the line voltage is turned on. To disable the protection:

a. Simultaneously depress the "0" and "1" keys. EEINIT <model> will be displayed.

b. Using the Up/Down annunciator keys select NO-PROTECT <OFF>.

c. Using the Up/Down arrows select NO-PROTECT <ON>.

d. Press "Enter".

3 - Troubleshooting

Post-repair Calibration

Calibration is required annually and whenever certain components are replaced. If components in any of the circuits listed below are replaced, the supply must be re-calibrated as described in Appendix B of the User's Guide.

a. A1 Control Board: Voltage or Current Monitor Amplifier circuits, High Bandwidth Current Amplifier,

or Current Monitor resistors R425/R431.

b. A2 Interface Board.

If the Interface board A2 is replaced, the supply must be initialized first (see "Initialization" later in this chapter) and then be calibrated.

Inhibit Calibration Switch

If "CAL DENIED" appears on the display when calibration is attempted, or if error code 401 occurs when calibrating over the GPIB, the internal INHIBIT CAL switch has been set. This switch setting prevents unauthorized or inadvertent power supply calibration. You must reset this switch in order to calibrate the supply.

This four-section switch, S201, is located on the A2 Interface board near the GPIB connector. The switch has 2 functions related to calibration. One is Inhibit Calibration. With this switch set the supply will not respond to calibration commands, thus providing security against unauthorized calibration. The other switch allows you to bypass the password in case it is forgotten.

Switch 3 Switch 4

Off Off

Off On

On Off

4 3 2 1

S201

Normal

Clear Password

Inhibit Calibration

Calibration Password

In order to enter the calibration mode, you must use the correct password as described in Appendix B of the Operating Manual. As shipped from the factory, the number 0 (zero) is the password. If you use an incorrect password, "OUT OF RANGE" will appear on the display for front panel calibration (or error code 402 occurs for GPIB calibration) and the calibration mode will not be enabled.

If you have changed the password and have forgotten it, you can set the configuration switch on A2 Interface board to bypass the password. See "Calibration Switch" paragraph above.

Troubleshooting - 3

Initialization

The dc power supply's GPIB address and model number as well as other constants which are required to program and calibrate the supply are stored in a EEPROM on the A2 Interface board. The Interface board also contains references and other components that will affect the alignment of the supply. If the Interface board is replaced, the supply must be reinitialized and calibrated. To initialize the power supply:

a. Enable the Calibration mode.

b. Simultaneously depress the "0" and "1" keys.

c. Using the Up/Down arrows select the appropriate model number.

d. Press "Enter".

The dc power supply will go through the turn-on self test sequence. It is now re-initialized and must be calibrated. See Appendix A of the User’s Guide for the calibration procedure.

ROM Upgrade

Identifying the Firmware

You can use the *IDN? query to identify the revision of the supply's firmware. The query will readback the revisions of the Primary Interface ROM located on the A2 Interface board. The manufacturer and model number of the supply are also returned. The following is a sample program:

10 ALLOCATE L$[42]

20 OUTPUT 705;"*IDN?"

30 ENTER 705;L$

40 DISP L$

50 END

The computer will display the manufacturer's name, the model number, a "0," and then the firmware revision. Example: "Agilent,66312A,0,A.00.01". The revision level of the ROM can also be found on the label affixed to the physical IC chip itself.

Upgrade Procedure

If the Interface board ROM is upgraded you can re-initialize the supply without affecting the calibration.

a. Enable the Calibration mode.

b. Simultaneously depress the "0" and "1" keys. EEINIT <model> will be displayed.

c. Using the Up/Down annunciator keys select ROMUPD <model>.

d. Using the Up/Down arrows select the appropriate model number.

e. Press "Enter".

The supply will go through the turn-on self test sequence and return to the power supply metering mode.

3 - Troubleshooting

Disassembly Procedures

The following paragraphs provide instructions on how to disassemble various components of the dc power supply. Once disassembled, the components can be reassembled by performing the disassembly instructions in reverse order. Figure 3-2 shows the location of the major components of the unit.

Figure 3-2. Component Location

WARNING: SHOCK HAZARD. To avoid the possibility of personal injury, turn off AC power and

disconnect the line cord before removing the top cover. Disconnect the GPIB cable and any loads, and remote sense leads before attempting disassembly.

CAUTION: Most of the attaching hardware is metric. Use of other types of fasteners will damage

threaded inserts. Refer to the list of required tools when performing disassembly and replacement.

List of Required Tools

a. 2PT Pozidriv screwdrivers.

b. T10 and T15 Torx screwdrivers.

c. Hex drivers: 7 mm for GPIB connector,

3/16" for RS-232 connector, 1/4" for front panel binding posts

d. Long nose pliers.

e. Antistatic wrist discharge strap.

Troubleshooting - 3

Cover, Removal and Replacement

a. Using a T15 Torx screwdriver, unscrew the two captive screws which hold the rear bezel to the dc

power supply, and then remove the two screws from the bottom of the case.

b. Slide the cover backward until it clears the rear of the power supply.

A2 Interface Board, Removal and Replacement

To remove the Interface Board, proceed as follows:

a. Remove the cover of the power supply as described under, "Cover Removal and Replacement."

b. Remove the two 7 mm and 3/16 inch hex screws that hold the GPIB and RS-232 connectors in place.

c. Slide the board forward until the notch on the right side of the Interface board aligns with the fan

spacer board. Rotate the right side up slightly to disengage the board from the slot in the left side of the chassis.

d. Unplug the cable from J206. Depress the release button located at the end of the connector where the

wires enter the housing.

e. Unplug the flat cables. Note the position of the conductive side for reinstallation. Connectors release

the cable by pulling out end tabs as shown by the arrows in the following figure.

f. To reinstall the Interface board, perform the above steps in reverse order.

Front Panel Assembly, Removal and Replacement

This procedure removes the front panel assembly from the dc power supply.

a. Remove the Power Supply Cover as described earlier in, "Top Cover Removal and Replacement."

b. Disconnect the cable between the Front Panel board and the Interface board at the Interface board. You

may have to remove the Interface board as described above to accomplish this.

c. Using a Torx T10 driver remove the three screws from each side of the supply that hold the front panel

brackets to the chassis.

d Slide the Front Panel assembly forward slightly to unplug the Binding Post connector and with a Torx

T15 driver remove the screw connecting the ground wire to the chassis.

e. To remove the left bracket, locate and carefully peel off the left vinyl trim to gain access to the side

screw that secures the front panel bracket the chassis. Using a Torx T15 driver remove the screw located behind the vinyl trim.

f. To remove the right bracket, depress the plastic tab located behind the front panel in the upper right

corner.

g. To reinstall the Front Panel Assembly, perform the above steps in reverse order.

3 - Troubleshooting

A3 Front Panel Board, Removal and Replacement

First remove the front panel assembly as described under, "Front Panel Assembly, Removal and Replacement." Once you have access to the front panel board perform these steps:

a. Remove the RPG knob by pulling it away from the front panel.

b. Pull back the right side of the board near the RPG about 1/8th of an inch. Slide the board to the left to

disengage the holding clips.

c. To reinstall the Front Panel board, perform the above steps in reverse order.

A1 Main Control Board

a. Remove the top cover and the A2 Interface board as described above.

b. Disconnect all cables going to connectors on the main control board.

NOTE: Be sure to note the position and orientation of all cables prior to removal so that no

mistake is made later when reinstalling these cables.

c. Disconnect the ground wire between the main board and the chassis. This wire is secured to the side of

the chassis near the AC input by a Torx T10 screw.

d. Remove three Torx T15 screws which secure the main control board to the chassis.

e. Slide the main board towards the front panel to release it from chassis mounted standoffs and then lift

the board out of the chassis.

T1 Power Transformer, Removal and Replacement

To remove the power transformer, the front panel assembly must first be removed to gain access to the bracket screws that hold the transformer in place.

a. Remove the front panel assembly as described above.

b. Remove the two Torx T10 screws securing the rear of the transformer bracket to the bottom of the

chassis and the two screws securing the front of the bracket.

c. Use long nose pliers to disconnect all wires going to the transformer terminals.

d. Lift the transformer out of the chassis.

NOTE: The AC power connections at the transformer primary are line voltage dependent. Refer

to Figure 3-3 subsequent reconnection.

Line Voltage Wiring

Figure 3-3 illustrates the primary wiring configuration of the power transformer for various ac line voltages. Use long nose pliers to disconnect the wires going to the transformer terminals.

NOTE: Install the correct fuse when changing the ac line voltage from a previous setting:

for 110/120 Vac: 2 A, Agilent p/n 2110-0002; for 220/230 Vac: 1 AT, Agilent p/n 2110-0007

Troubleshooting - 3

white/red/grey

grey

white/red/grey

orange

white/yellow white/violet

white/red/grey

white/yellow white/violet

white/red/grey

grey

orange (spare)

orange

white/yellow white/violet

orange

(spare)

orange

white/yellow white/violet

white/red

white/black

white/brown

Figure 3-3. Transformer Wiring

white/red

red

white/black black

white/brown

Principles of Operation

Introduction

This section describes the different functional circuits used in the dc power supply models covered in this manual. First, the I/O external signals that connect to the Agilent power supply are described. Next, the overall block diagrams for the dc power supply are described in detail.

The simplified block diagrams in this section show the major circuits on the dc power supply as well as the signals between circuits. They also show the reference designations of some of the components in the functional circuit. These same reference designators are shown in the schematic diagrams in Section 6.

I/O Interface Signals

Table 4-1 describes the interface signals between the power supply and the end user (or other external circuits and devices).

Table 4-1. Power Supply Interface signals

Connector Signal Description

Front panel outputs +OUT

-OUT

Rear panel output/sense screw terminals

INH/FLT connector pin 1

RS-232 connector XON-XOFF

GPIB connector GPIB /IEEE 488 Provides the interface to an external GPIB controller

Ac input connector ac mains Can be 100 Vac, 120 Vac, 220 Vac or 240 Vac Input

+OUT

-OUT + sense

- sense common

pin 2 pin 3 pin 4

RTS-CTS DTR-DSR NONE

Positive DC output voltage Negative DC voltage (or return)

Positive DC output voltage Negative DC voltage (or return) +OUT sensing terminal

-OUT sensing terminal connected to ground conductor

Set SENSE switch to "Remote" when using the sensing

terminals.

FLT/INH mode FLT output OUT 0 FLT Common OUT 1 INH Input IN 2/OUT 2 INH Common Common

as-shipped configuration

uses ASCII control codes DC# and DC1 uses Request-To-Send and Clear-To-Send lines uses Data-Terminal-Ready and Data-Set-Ready lines there is no flow control

Digital I/O mode

4 - Principles of Operation

A3 Front Panel Circuits

As shown in Figure 4-1, the supply's front panel assembly contains a circuit board, a keypad, a liquid crystal display (LCD), and a rotary control (RPG) for the output voltage and current. With the exception of the RPG (A3G1), the A3 Front Panel board is an assembly-level replaceable part. A separate front panel binding post board is also included on the unit. It is also available as an assembly-level replaceable part.

The A3 front panel board contains microprocessor circuits, which decode and execute all keypad and RPG commands that are transferred to the power supply output via the serial I/O port to the primary interface circuits on the A2 interface board. The front panel microprocessor circuits also process power supply measurement and status data received on the serial I/O port. This data is displayed on the LCD.

A2 Interface Circuits

The circuits on the A2 interface board provide the interface between the GPIB interface, RS-232 interface, and front panel interface and the dc power supply. Communication between the power supply and a GPIB controller is processed by the GPIB interface and the primary microprocessor circuits on the A2 board. The A2 Interface board is assembly-level replaceable; it contains no user-replaceable parts.

With the exception of the front panel microprocessor, all digital circuits, analog-to-digital converters (ADC) and digital-to-analog converters (DAC) in the dc power supply are located on the A2 Interface board. All control signals between the A2 interface board and the A1 main board are either analog or level signals.

Primary Interface

The primary microprocessor circuits (DSP, ROM, and RAM chips) decode and execute all instructions and control all data transfers between the controller and the secondary interface. The primary microprocessor circuits also processes measurement and status data received from the secondary interface.

A Dual Asynchronous Control chip on the A2 board converts the RS-232, RI/DFI, and front panel data into the primary microprocessor's 8-bit data format. The serial data is transferred between the primary interface and the secondary interface via a serial bus and optical isolator chips. These chips isolate the primary interface circuits (referenced to earth ground) from the secondary interface circuits.

Secondary Interface

The secondary interface circuits include a programmed logic array, EEPROM, boot-ROM, 8 and 12-bit DAC circuits, and 8 and 16-bit ADC circuits. The programmed logic array translates the serial data received from the primary interface into a corresponding digital signal for the appropriate DAC/ADC circuits. The logic array is also connected directly to four DAC/ADC circuits. Under control of the logic array, the selected DAC converts the data on the bus into an analog signal. Conversely, the selected ADC converts the analog signals from the A1 board into a digital signal.

The logic array also directly receives status information from the A1 main board via three level-sensitive signal lines, which inform the array of the following operating conditions: constant voltage mode (CV_Detect*), constant current mode (CC_Detect*), and overvoltage (OV_Detect*). The PM_Inhibit control signal is used to shut down the bias voltage to the output stages and keep the power supply output off. The OV_SCR* control signal is used to fire the SCR and keep the power supply output off when an overvoltage condition has occurred.

Principles of Operation - 4

Figure 4-1. A2/A3 Block Diagram

4 - Principles of Operation

The EEPROM (electrically erasable programmable read-only memory) chip on the A2 interface board stores a variety of data and configuration information. This information includes calibration constants, GPIB address, present programming language, and model-dependent data, such as the minimum and maximum values of voltage and current. One of the EEPROM storage locations holds a checksum value which is used to verify the integrity of the EEPROM data. Access to the calibration data in the EEPROM is controlled by the combination of a password and switch settings on A2S201, located on A2 interface board (see Chapter 3 "Inhibit Calibration Switch").

The Dual 12-bit DAC converts the programmed value of voltage and current on the bus into the CV_Prog and CC_Prog signals, which are sent to the CV control circuits in order to control the magnitude of the output voltage in the CV mode and output current in CC mode. The CV_Prog and CC_Prog signals are in the 0 to -5 V range, which corresponds to the zero to full-scale output ratings of the dc power supply.

The Quad 8-bit DAC converts programmed information for the following circuits into analog format: overvoltage setting (OV_Prog), and fan speed programming (Fan_Prog). The OV_Prog signal is applied to the OV detect circuit, which compares the programmed overvoltage setting with the actual output voltage. The Fan_Prog signal is applied to the fan speed control circuit in order to speed up the fan as temperature increases, and to slow the fan speed down as temperature decreases.

The 16-bit ADC in conjunction with a 4x1 multiplexer returns data from the following measurement signals to the logic array: monitored output voltage (VMon), monitored high-range current (Imon_H), monitored low-range current (Imon_L), and monitored peak current (Imon_P). All measurement signals are in the range of 0 to +5V, which corresponds to the zero to full-scale readback capability of the dc power supply.

The 8-channel, 8-bit ADC returns the following signals to the logic array: high-range output current (Imon_H), overvoltage (V_Mon), ambient temperature (Temp_Amb), heatsink temperature (HS_Therm), and output fuse state (Fuse). Four of these signals are for fan control. The logic array varies the Fan_Prog signal depending upon the ambient temperature, the heatsink temperature, and the present output voltage and current. The Fuse signal informs the logic array if the output fuse (F309) is open.

A1 Main Board Circuits

Power Circuits

As shown in Figure 4-2, the power circuits consist of: input power rectifiers and filter, an output regulator, a downprogrammer circuit, current-monitoring resistors, an overvoltage SCR, and an output filter.

The ac input rectifier and filter converts ac input to a dc level. The output regulator regulates this dc level at the output of the power supply. The output regulator stage consists of two parallel NPN series regulators mounted on a heatsink and connected between the +Rail and the +Ouput. The conduction of these series regulators is increased or decreased by the Control signal from the CV/CC control circuits in order to regulate the output voltage (in CV mode), or output current (in CC mode).

An NPN downprogramming transistor is connected between the +Output and the -Rail. The conduction of the downprogramming transistor is controlled by the DP_Control signal from the CV/CC control circuits. Whenever the output voltage is greater than the programmed voltage setting, the downprogramming transistor conducts and shunts current away from the load until the output voltage equals the programmed setting.

Principles of Operation - 4

Figure 4-2. A1 Block Diagram

4 - Principles of Operation

The SCR, connected across the output, will fire and short the output when an overvoltage condition is detected. The SCR is controlled by the OV_SCR* signal from the crowbar control circuit (described in the next section).

Two current shunt resistors (RmHi and RmLo) monitor the output current. RmHi monitors the high current range; RmLo monitors the low current range. Shunt clamps are connected in parallel across RmLo to limit the current to approximately 25 mA (the maximum rating of the low current range).

The output filter capacitor provides additional filtering of the dc output.

Control Circuits

As shown in Figure 4-2, the control circuits consist of the CV/CC control, output voltage/current monitor, bias supplies, and SCR control.

The CV/CC control circuits provide a CV control loop and a CC control loop. For any value of load resistance, the supply must act either as a constant voltage (CV) or as a constant current (CC) supply. Transfer between these modes is accomplished automatically by the CV/CC control circuit at a value of load resistance equal to the ratio of the programmed voltage value to the programmed current value. A low level CV_Detect* or CC_Detect* signal is returned to the secondary interface to indicate that the corresponding mode is in effect.

With the CV loop in control, the output voltage is regulated by comparing the programmed voltage signal CV_Prog (0 to -5V) with the output voltage monitor signal VMon. The VMon signal is in the 0 to +5 V range, which corresponds to the zero to full-scale output voltage range of the supply. If the output voltage exceeds the programmed voltage, the Control signal goes low, causing the output regulator to conduct less and decrease the output voltage. Conversely, if the output voltage is less than the programmed voltage, the Control signal goes high, causing the regulator to conduct more and increase the output voltage. Depending upon the position of the Sense switch, the output voltage is either monitored at the supply's output terminals (local), or at the load (remote), using the +S and -S terminals with remote sense leads connected to the load. If the output voltage goes higher than the programmed value, the downprogramming stage is turned on.

With the CC loop in control, the output current is regulated by comparing the programmed current signal CC_Prog (0 to -5V), with the output current monitor signal Imon_H. The Imon_H signal is produced by measuring the voltage drop across current monitoring resistor and is in the 0 to +3.5 V range, which corresponds to the zero to full-scale output current range. If the output current exceeds the programmed value, the Control signal goes low, causing the output regulator to conduct less and thus decrease the output current. Conversely, if the output current is less than the programmed value, the Control signal goes high, causing the output transistors to conduct more and increase the output current. A gross current limit circuit protects the output if the output current exceeds the maximum current rating of the unit.

When the downprogramming stage is turned on (in either CV or CC mode), the CV/CC control circuit causes the Control signal to go low, which in turn causes the downprogramming transistors to conduct current away from the load and speed up downprogramming.

During operation, a PM_Inhibit signal will cause the output stage bias/shutdown circuit to turn off the gated 15 V bias voltages and shut down the output if any of the following occur:

The output is programmed off.

An overvoltage condition is detected (OV_Detect* signal is received).

The line voltage falls below 90 volts (approximately).

Principles of Operation - 4

Current readback is provided by three separate circuits. The previously discussed high range current signal (Imon_H) returns the high range currrent measurement. When the unit is operating in the low current readback mode, a separate low range current shunt and amplifier provides low-current readback via the Imon_L signal . A shunt clamp (Q304 and Q305) clamps the voltage across RmLo to approximately 1.8 V. The third current readback circuit consists of a high bandwidth current amplifier that returns dynamic current measurements from the output filter capacitor via the Imon_P signal. Note that the Imon_H and the Imon_P dignal are combined to return the actual output current measurement.

An overvoltage detect circuit compares the output voltage to the programmed overvoltage setting. When the output exceeds the programmed setting, the OV_Detect* signal goes low, which informs the logic aray that an OV condition has occurred. The crowbar control circuit is enabled when the OV_SCR* signal is received. When an overvoltage condition occurs, the SCR control circuit generates the OV signal, which causes the following actions to occur:

1. The SCR fires, shorting the supply's output.

2. The microprocessor circuits are notified of the OV condition (OV_Detect* is low) in order to program the ouput off, turn off the 15V bias supply, and update the status of the unit.

3. The PM_Inhibit signal goes high, programming the output off and shutting down the +15V bias for the output regulators.

4. When a output protection clear command is executed, the microprocessor circuits resets the OV circuits, tutns on the +15V bias supply, and programs the output to its previous level.

The fan driver control circuit provides the DC voltage to operate the cooling fan. The Fan_Prog signal from the secondary interface circuit varies this voltage according to the ambient and heaatsink temperature as well as the output voltage and current of the supply.

Replaceable Parts List

Introduction

This section lists the replaceable parts for Agilent models 66312A and 6612B. Refer to Figure 5-1 for the location of mechanical parts with the reference designators MP. Refer to the board location diagrams in Chapter 6 for the location of electrical parts.

Table 5-1. Chassis, Electrical

Designator Part_Number Qty Description

A1 5063-3428 1 Control PCA

A2 5063-3429 1 Interface PCA for 6612B

A2 5063-3439 1 Interface PCA for 66312A

A3 5063-3430 1 Front Panel PCA

A4 06611-60022 1 Binding Post PCA

B1 06632-60002 1 Fan Assembly

G1 0960-0892 1 Rotary pulse generator

T1 9100-5399 1 Main Power Transformer

W-1 06611-80003 1 Primary Power Cable

W-2 06611-80006 1 Interface Power Cable

W-3 06611-80004 1 Secondary Power Cable

W-4 06611-80005 1 Secondary Bias Cable

W-5 06611-80007 1 Output Cable

W-5 06011-80003 1 Magnetic Core

W-6 5080-2457 1 Display Power/Comm Cable

W-7 5080-2452 1 Interface Power Cable

W-8 5080-2448 1 Interface Signal/Bias Cable

W9 06611-60056 2 T1 Primary Jumper

8120-4383 1 Line Cord, (std U.S. 115Vac input)

8120-1351 1 Line Cord, Option 900,

8120-1369 1 Line Cord, Option 901,

8120-1689 1 Line Cord, Option 902,

8120-0698 1 Line Cord, Option 904,

8120-2104 1 Line Cord, Option 906,

8120-2956 1 Line Cord, Option 912,

8120-4211 1 Line Cord, Option 917,

8120-4753 1 Line Cord, Option 918,

5 - Replaceable Parts

Table 5-2. Chassis, Mechanical

Designator Part_Number Qty Description

MP1 06611-00001 1 Chassis

MP2 5063-3413 1 Front Panel

MP3 06611-00003 1 Side Bracket, Left

MP4 06611-00005 1 Side Bracket, Right

MP5 06611-00004 1 Transformer Bracket

MP6 1510-0091 2 Binding Post

MP7 0590-0305 2 Hex Nut 6-32 w/Lockwasher

MP8 33120-87401 1 Knob

MP9 06612-40002 1 Window (6612B)

MP9 66312-40001 1 Window (66312A)

MP10 06611-40001 1 Pushrod (Ref Line Switch)

MP11 06611-40002 1 Keypad

MP12 06611-00002 1 Cover

MP13 03478-88304 1 Rear Bezel

MP14 5041-8801 4 Foot

MP15 0515-0430 13 Screw M4x0.7x8mm, Torx T15, Pan, Conical cup

MP16 5020-2860 1 Main Heat Sink

MP17 1400-1826 6 Spring Clip

MP18 0515-0433 6 Screw M3x0.5x6mm, Torx T10, Pan, Conical cup

MP19 06611-20003 1 Insulator Pad

MP20 06612-20002 1 Thermal Insulator

MP21 0380-0644 2 Stud Mounted Standoff (ref GPIB Connector)

MP22 2190-0586 2 Helical Lock Washer, M4

MP23 3050-0849 2 Flat Washer, #10

MP24 06611-40006 1 Fan Spacer

MP25 0515-0374 5 Screw M3x0.5x10mm, Torx T10, Pan, Conical cup

MP26 06611-40005 1 Support Plate

MP27 06611-80002 1 Rear Panel Label

MP28 1400-0493 1 Cable Tie

MP29 1400-1281 3 Cable Clip

MP30 5001-0438 4 Side Trim

MP31 0515-2535 2 Screw, M3x0.5x8mm, Torx T10, Pan Head

MP32 1252-1488 1 Terminal Block, 4 Position, RI/DFI

MP33 0360-2604 1 Terminal Block, 5 Position, Output/Sense

MP34 0370-2862 1 Pushbutton (Ref Sense Switch)

MP35 1400-0977 2 Battery Clip (Cover Ground)

MP36 1252-3056 2 Screw Lock Kit (ref RS232 Connector)

5962-0872 1 Operating Guide

5962-8108 1 Programming Guide

5962-0874 1 Service Guide

Figure 5-1. Mechanical Parts ldentification

Replaceable Parts - 5

5 - Replaceable Parts

Table 5-3. A1 Control PC Board Assembly

Designator Part_Number Qty Description

A1 5063-3428 1 Control PC Assembly

C301, 302 0160-4801 2 Cap 100 pF 5%

C303 0160-5422 1 Cap 0.047 uF 20%

C304 0160-4834 1 Cap 0.047 uF 10%

C305 0160-4846 1 Cap 1500 pF 100V

C306 0180-4129 1 Cap 1 uF 35V

C307 0160-4834 1 Cap 0.047 uF 10%

C308, 309 0160-8180 2 Cap 1000 pF

C310 0180-4136 1 Cap 10 uF 20V

C313 0160-0161 1 Cap 0.01 uF 10%

C314 0160-5471 1 Cap 0.1 uF 5% 50V

C315 0160-4801 1 Cap 100 pF 5%

C316 0160-4833 1 Cap 0.022 uF 10%

C317 0160-4812 1 Cap 220 pF 5%

C318 0160-4801 1 Cap 100 pF 5%

C319 0160-4812 1 Cap 220 pF 5%

C320 0160-4801 1 Cap 100 pF 5%

C321 0160-4833 1 Cap 0.022 uF 10%

C322, 323 0160-4801 2 Cap 100 pF 5%

C324 0160-6827 1 Cap 0.022 uF 400V

C325 0160-4801 1 Cap 100 pF 5%

C326, 327 0160-4791 2 Cap 10 pF 5% 100V

C328 0160-7277 1 Cap 2.2 uF 50V

C329, 330, 331 0160-4791 3 Cap 10 pF 5% 100V

C332 0160-4831 1 Cap 4700 pF 10%

C333 0160-4807 1 Cap 33 pF 5% 100V

C334 0160-4801 1 Cap 100 pF 5%

C335 0160-4807 1 Cap 33 pF 5% 100V

C336 0160-4814 1 Cap 150 pF 5%

C337, 338 0160-5422 2 Cap 0.047 uF 20%

C339 0160-4814 1 Cap 150 pF 5%

C340 0160-5422 1 Cap 0.047 uF 20%

C341 0160-4831 1 Cap 4700 pF 10%

C342, 344 0160-5422 2 Cap 0.047 uF 20%

C345 0160-4807 1 Cap 33 pF 5% 100V

C346 - 350 0160-5422 5 Cap 0.047 uF 20%

C352, 353 0160-5422 2 Cap 0.047 uF 20%

C354 0180-4033 1 Cap 2200 uF 35 V

C355 0180-2980 1 C-F 1000 uF 50V

C356 - 363 0160-5422 8 Cap 0.047 uF 20%

C364, 365 0160-4835 2 Cap 0.1 uF 10% 50V

Designator Part_Number Qty Description

C366 0160-4918 1 Cap 0.022 uF 10%

C367, 368 0160-4835 2 Cap 0.1 uF 10% 50V

C369 0160-5422 1 Cap 0.047 uF 20%

C370 0160-5932 1 Cap 0.47 uF 250VAC

C371, 372 0180-4818 2 Cap 8200 uF 16V

C373 0160-8232 1 Cap 50 uF 30V

C374 0180-4138 1 Cap 8200 uF 50V

C375 0180-0197 1 Cap 2.2 uF 20V TA

C376 0180-4129 1 Cap 1 uF 35V

C377 0160-5422 1 Cap 0.047 uF 20%

C378, 379 0180-4129 2 Cap 1 uF 35V

C380, 381 0150-0081 2 Cap 0.01 uF +80

C383 0180-4129 1 Cap 1 uF 35V

C384 0160-4807 1 Cap 33 pF 5% 100V

C385 0160-4787 1 Cap 22 pF 5% 100V

C386 0160-4511 1 Cap 220 pF 200V

C387 0160-5644 1 Cap 0.033 uF 50V

CR301 06611-60008 1 Assembly-REG/HS

2200-0143 1 Ref CR301 Machine Screw 4-40

1884-0310 1 Ref CR301 Thyristor, SCR MCR69-3

1901-0987 1 Ref CR301 Diode, Power (see CR301)

0590-0199 1 Ref CR301 Hex Nut W/Lockwasher

1205-0282 1 Ref CR301 Heat Sink

D301 - 310 1901-0731 10 Diode

D311, 312 1901-1087 2 Diode, Power

D312 1901-0987 1 Diode, Power (see CR301)

D313 1901-1098 1 Diode

D315 1901-0880 1 Diode

D316 1901-0987 1 Diode, Power (see Q304)

D317 1901-1098 1 Diode

D318 1901-0880 1 Diode

D319, 321, 322 1901-1098 3 Diode

D323, 325 1901-0880 2 Diode

D326 - 328 1901-1098 3 Diode

D329 1901-0880 1 Diode

D330 5063-3416 1 Bridge Recifier Assembly

0535-0031 1 Ref D330 Hex Nut M3x0.5 w/Lockwasher

1205-0219 1 Ref D330 Heat Sink

0515-0374 1 Ref D330 Screw M3x0.5x10mm, Torx T10, Pan

1906-0349 1 Ref D330 Rectifier

Replaceable Parts - 5

5 - Replaceable Parts

Designator Part_Number Qty Description

D334 1901-0880 1 Diode

D336 - 341 1901-1098 6 Diode

F301 2110-0303 1 Fuse 2AT 250V (for 110/120 Vac)

2110-0007 1 Fuse 1AT 250V (for 220/230 Vac)

2110-0927 1 Ref F301 Fuseholder with cap

F302 2110-0671 1 Fuse 0.125A 125V

F303 2110-0699 1 Fuse, Submin 5AM

F304 2110-0671 1 Fuse 0.125AM 125V

F305, 306 2110-0699 2 Fuse, Submin 5AM

F307 2110-0671 1 Fuse 0.125AM 125V

F308 2110-0699 1 Fuse, Submin 5AM

F309 2110-0967 1 Fuse, Submin 4 AM

F310 2110-0699 1 Fuse, Submin 5AM

J303 1251-4245 1 Connector, 2 Pin Male

J304 1251-8512 1 Connector

J305 1252-0063 1 Connector

J307 1252-5977 1 Connector

J308 1252-3771 1 AC Input Connector

J309 1252-7041 1 Connector

J314 1252-0063 1 Connector

CR301 06611-60008 1 Connector

Q301 1854-1330 1 Transistor, NPN

Q302 06611-60007 1 Assembly-REG/HS

1205-0282 1 Ref Q302 Heat Sink

1251-3411 2 Ref Q302 Connector

1855-0831 1 Ref Q302 MOSFET N-Chan

Q303 1855-0725 1 MOSFET

Q304 06611-60006 1 Assembly-REG/HS Q304/D316

0340-0950 1 REF Q304 Insulator

0590-0199 1 REF Q304 Hex Nut W/Lockwasher

2200-0143 1 REF Q304 Machine Screw 4-40

3050-1021 1 REF Q304 Shoulder Washer

1855-0726 1 REF Q304 MOSFET P-Chan

1901-0987 1 REF Q304 Diode, power

1205-0282 1 REF Q304 Heat Sink

Q305 5060-3245 1 Assembly-HS,REG

1205-0282 1 Ref Q305 Heat Sink

1854-0828 1 Ref Q305 Transistor, NPN

Q306 1853-0497 1 Transistor, PNP

Q307 1855-0725 1 MOSFET

Q308 - 310 1854-1174 3 Transistor, NPN

Designator Part_Number Qty Description

R301 0698-3441 1 Res 215 Ohm 1%

R302 0698-3430 1 Res 21.5 Ohm 1%

R303 0698-3441 1 Res 215 Ohm 1%

R304 0683-4725 1 Res 4.7K 5% 0.25W

R305 0698-3441 1 Res 215 Ohm 1%

R306 0683-2255 1 Res 2.2M 5% 0.25W

R307 0683-0475 1 Res 4.7 Ohm 5% 0.25W

R308 0698-3430 1 Res 21.5 Ohm 1%

R309 0698-0085 1 Res 2.61K 1%

R310 - 312 0757-0280 3 Res 1K 1% 0.125W

R314 0757-0316 1 Res 42.2 Ohm 1%

R315 - 319 0757-0280 5 Res 1K 1% 0.125W

R320 0698-0092 1 Res 2.61K 1%

R321 0698-3441 1 Res 215 Ohm 1%

R322, 323 0757-0280 2 Res 1K 1% 0.125W

R324 0757-0317 1 Res 1.33K 1% 0.125W

R325 0698-6360 1 Res 10K 0.1%

R326, 327 0757-0442 2 Res 10K 1% 0.125W

R328, 329 0698-6360 2 Res 10K 0.1%

R330 0698-3496 1 Res 3.57K 1% 0.125W

R331 7175-0057 1 Jumper Wire #22

R332 0698-6360 1 Res 10K 0.1%

R333, 334 0757-0442 2 Res 10K 1% 0.125W

R335 0757-0449 1 Res 20K 1% 0.125W

R336 0698-6360 1 Res 10K 0.1%

R337 0757-0442 1 Res 10K 1% 0.125W

R338 0698-8234 1 Res 12.1K 0.1%

R339 0698-8827 1 Res 1M 1% 0.125W

R340 0698-6533 1 Res 12.5K 0.1%

R341 - 343 0683-0475 3 Res 4.7 Ohm 5% 0.25W

R344 0757-0442 1 Res 10K 1% 0.125W

R345 0698-6630 1 Res 20K 0.1%

R346 0698-3156 1 Res 14.7K 1%

R347 0757-0441 1 Res 8.25K 1%

R348 0698-6392 1 Res 22K 0.1%.125W

R349 0757-0441 1 Res 8.25K 1%

R350 0698-3156 1 Res 14.7K 1%

R351 0757-0442 1 Res 10K 1% 0.125W

R352 0698-3156 1 Res 14.7K 1%

R353 0811-1669 1 Res 1.8 Ohm 5% 2W

R354 0757-0279 1 Res 3.16K 1%

Replaceable Parts - 5

5 - Replaceable Parts

Designator Part_Number Qty Description

R355 0757-0442 1 Res 10K 1% 0.125W

R356 0698-3156 1 Res 14.7K 1%

R357 0757-0442 1 Res 10K 1% 0.125W

R358 7175-0057 1 Jumper Wire #22

R359 0698-3156 1 Res 14.7K 1%

R360 0698-3160 1 Res 31.6K 1%

R361 0698-3162 1 Res 46.4K 1%

R362 0757-0459 1 Res 56.2K 1%

R363 0698-6631 1 Res 2.5K 0.1%

R364 0698-0084 1 Res 2.15K 1%

R366 0757-0449 1 Res 20K 1% 0.125W

R367 0757-0459 1 Res 56.2K 1%

R368 0698-3162 1 Res 46.4K 1%

R369 0757-0455 1 Res 36.5K 1%

R370 0698-0084 1 Res 2.15K 1%

R371 0757-0449 1 Res 20K 1% 0.125W

R372 0698-3160 1 Res 31.6K 1%

R373 0698-0082 1 Res 464 Ohm 1% 0.125W

R375 0698-6631 1 Res 2.5K 0.1%

R376 0757-0340 1 Res 10K 1% 0.25W

R377 0757-0394 1 Res 51.1 Ohm 1% 0.125W

R378 0698-3445 1 Res 348 Ohm 1% 0.125W

R379 0757-0199 1 Res 21.5K 1%

R380 0698-3155 1 Res 4.64K 1%

R381 0757-0419 1 Res 681 Ohm 1% 0.125W

R382 0698-3157 1 Res 19.6K 1%

R383, 385 0757-0199 2 Res 21.5K 1%

R386 0757-1093 1 Res 3K 1% 0.125W

R387 0698-3157 1 Res 19.6K 1%

R388 0757-0419 1 Res 681 Ohm 1% 0.125W

R389 0757-0459 1 Res 56.2K 1%

R390 0698-3155 1 Res 4.64K 1%

R391 0698-3153 1 Res 3.83K 1%

R392 0757-1093 1 Res 3K 1% 0.125W

R393 0699-1972 1 Res 1.74M 1% 0.125W

R394 0698-8816 1 Res 2.15 1%

R395 0698-8827 1 Res 1M 1% 0.125W

R396 7175-0057 1 Jumper Wire #22

R397 0698-3359 1 Res 12.7K 1% 0.125W

R398 0698-8816 1 Res 2.15 1%

R401 0698-3558 1 Res 4.02K 1%

Designator Part_Number Qty Description

R402 0699-2048 1 Res 800K 0.1%

R403 0757-0289 1 Res 13.3K 1%

R404 0757-0465 1 Res 100K 1%

R405 0698-8826 1 Res 825K 1%

R406 0757-0397 1 Res 68.1 Ohm 1%

R407 0757-0199 1 Res 21.5K 1%

R408 0698-7332 1 Res 1M 1% 0.125W

R409 0698-4486 1 Res 24.9K 1% 0.125W

R410 0757-0414 1 Res 432 Ohm 1% 0.125W

R411 0699-1972 1 Res 1.74M 1% 0.125W

R412 0757-0416 1 Res 511 Ohm 1% 0.125W

R413 0698-3279 1 Res 4.99K 1%

R414 0757-0438 1 Res 5.11K 1%

R415 0811-3290 1 Res 0.1 Ohm 5% 2W

R416 0698-4202 1 Res 8.87K 1%

R418, 419 7175-0057 2 Jumper Wire #22

R421 - 423 7175-0057 3 Jumper Wire #22

R425 0699-4484 1 Res 72 Ohms

R430 0686-2225 1 Res 2.2K 5% 0.5W

R431 0811-3771 1 Res 0.25 Ohm 1%

R432, 433 0699-0267 2 Res 10K 0.05% 0.1W

R434, 435 0699-1513 2 Res 40K 0.05% 0.1W

R436 - 438 0699-4707 3 Res 0.25 Ohm 5% 3W

R439 0699-1867 1 Res 3.2K 0.1%

R440 0699-2246 1 Res 25K 0.05%

R441 0699-1867 1 Res 3.2K 0.1%

R442 0699-2246 1 Res 25K 0.05%

R443 0698-8834 1 Res 9K 0.1% 0.125W

R444, 445 0699-1866 2 Res 2.7K 0.1% 0.1W

R446 0698-8834 1 Res 9K 0.1% 0.125W

R447 0698-3456 1 Res 287K 1%

R448, 449 0757-0407 2 Res 200 Ohm 1% 0.125W

R450, 451 0757-0433 2 Res 3.32K 1%

R452, 453 0698-8812 2 Res 1 Ohm 1% 0.125W F

R454 0757-0338 1 Res 1K 1% 0.25W F

R455, 456 0757-0401 2 Res 100 Ohm 1% 0.125W

R457 0757-0407 1 Res 200 Ohm 1% 0.125W

R458 0698-3160 1 Res 31.6K 1% 0.125W

RT301 0837-0397 1 Thermistor

S301 3101-2808 1 Push Button Switch, DPST

S302 3101-2894 1 Push Button Switch, DPDT

Replaceable Parts - 5

5 - Replaceable Parts

Designator Part_Number Qty Description

T301 9100-4350 1 Current Transformer

U302 1990-0543 1 Opto-Isolator

U304 5060-3232 1 Assembly-HS

1826-0106 1 Ref U304 Integrated Circuit

1205-0282 1 Ref U304 Heat Sink

U305 5063-2389 1 Assembly-REG/HS

1826-1597 1 Ref U305 Integrated Circuit

1205-0402 1 Ref U305 Heat Sink

U306 5060-3229 1 Assembly-HS

1826-0214 1 Ref U306 Integrated Circuit

1205-0282 1 Ref U306 Heat Sink

U307 5060-2948 1 Assembly-HS

1826-0122 1 Ref U307 Integrated Circuit

1205-0282 1 Ref U307 Heat Sink

U308, 309 1826-1533 2 Integrated Circuit

U311 1858-0077 1 Transistor Array

U312 1858-0076 1 Transistor Array

U315, 316 1826-1533 2 Integrated Circuit

U318, 319 1826-3521 2 Integrated Circuit

U320, 321 1826-1533 2 Integrated Circuit

U322 1826-1878 1 Integrated Circuit

U324 1826-2252 1 Integrated Circuit

U325 1826-3521 1 Integrated Circuit

U326 1826-0962 1 Integrated Circuit

U327 1826-0065 1 Integrated Circuit

U328 1826-1370 1 Integrated Circuit

VR301, 302 1902-0958 2 Zener Diode 10V 5%

VR303 1902-0955 1 Zener Diode 7.5V 5%

VR304 1902-0957 1 Zener Diode 9.1 V 5%

VR305 1902-3092 1 Zener Diode 4.99V 2%

Table 5-4. A4 Binding Post PC Board Assembly

Designator Part_Number Qty Description

A4 06611-60022 1 Binding Post PCA

C601, 602 0150-0081 2 Capacitor, 0.01 uF

C605 0160-0128 1 Capacitor, 2.2 uF

J615 1252-0056 1 Connector, 4 pin

R800 0698-8812 1 Resistor, 1 ohm

Diagrams

Introduction

This chapter contains drawings and diagrams for troubleshooting and maintaining the Agilent Model 66312A Dynamic Measurement DC Source and the Agilent Model 6612B System DC Power Supply. Unless otherwise specified in the drawings, a drawing or diagram applies to both models and input voltage options.

General Schematic Notes

a All resistors are in ohms 1%, 1/8 W, unless otherwise specified.

a All capacitors are in microfarads unless otherwise specified.

a Unless otherwise noted, bias connections to integrated-circuit packages are as follows:

Common 5 V 14-pin packages pin 7 pin 14 16-pin packages pin 8 pin 16 20-pin packages pin 10 pin 20

Backdating

a REVISION “A” boards: The schematic sheets in this manual apply to Revision “B” Control Boards. The revision number of the board is located under the Agilent logo (next to U302). Revision A boards do not contain the following components that are shown in this manual:

C387, D339, D340, D341, R353, R331, R358, R396, R458

6 - Diagrams

Ref. X Y Ref. X Y Ref. X Y Ref. X Y Ref. X Y

Table 6-1. A1 Board Component Locations

C301 5.125 3.975 C370 1.125 0.625 J303 10.72 2.15 R352 2.4 2.025 R425 4.1 2.4 C302 1.725 3.975 C371 8.925 2.975 J304 10.3 5.35 R353 1.8 3.5 R430 6.275 5.35 C303 10.55 3.7 C372 9.725 1.775 J305 10.45 4.325 R354 2.775 1.425 R431 6.625 2.4 C304 0.75 2.725 C373 1.475 3.575 J307 7.7 1.7 R355 5.15 0.7 R432 2.0 3.05 C305 1.8 2.225 C374 9.1 4.55 J308 0.587 1.368 R356 2.775 1.325 R433 2.0 3.15 C306 8.05 3.625 C375 6.275 3.325 J309 0.256 4.49 R357 1.85 1.4 R434 1.35 2.75 C307 1.55 3.4 C376 8.3 0.775 J314 7.2 5.3 R358 6.5 3.5 R435 1.35 2.85 C308 1.35 1.9 C377 3.5 3.9 Q301 5.495 4.2 R359 2.85 1.725 R436 1.55 5.35 C309 0.95 0.465 C378 8.025 2.2 Q302 3.8 2.8 R360 4.25 0.7 R437 0.475 5.35 C310 6.275 5.15 C379 7.65 2.35 Q303 0.832 4.571 R361 7.825 3.975 R438 4.125 5.35 C313 2.25 0.25 C380 0.475 3.96 Q304 4.85 2.8 R362 5.05 0.25 R439 5.725 2.1 C314 2.5 2.675 C381 1.01 4.285 Q305 7.35 4.925 R363 1.45 3.4 R440 6.175 1.9 C315 3.725 0.875 C383 4.9 4.6 Q307 3.323 4.571 R364 5.75 4.65 R441 6.175 2.0 C316 6.825 3.25 C384 4.025 2.105 Q308 1.339 4.571 R366 3.525 1.325 R442 6.175 1.7 C317 6.75 4.55 C385 4.85 1.75 Q309 2.583 4.571 R367 6.325 0.7 R443 4.7 1.7 C318 6.825 3.875 C386 0.68 3.85 R301 2.625 3.975 R368 4.025 0.7 R444 4.25 1.8 C319 4.3 4.05 C387 5.8 1.075 R302 1.125 3.975 R369 8.475 2.35 R445 4.25 2.1 C320 2.025 3.975 Cr301 3.5 3.575 R303 3.825 4.35 R370 3.225 1.025 R446 4.7 1.9 C321 6.325 2.8 D301 9.0 2.175 R304 8.275 3.975 R371 3.625 0.875 R447 5.25 0.7 C322 6.725 3.875 D302 10.52 3.6 R305 1.525 3.975 R372 5.55 3.525 R448 6.025 3.15 C323 4.5 4.05 D303 9.2 2.175 R306 2.4 2.325 R373 4.35 0.7 R449 6.025 3.05 C324 2.725 0.525 D304 10.35 3.6 R307 6.15 3.525 R375 0.75 2.9 R450 7.025 2.8 C325 4.7 1.6 D305 8.85 2.2 R308 3.7 4.4 R376 10.12 4.5 R451 6.125 3.25 C326 2.025 3.25 D306 8.7 2.25 R309 2.725 3.975 R377 3.5 3.775 R452 4.525 3.3 C327 6.325 2.1 D307 8.7 3.775 R310 7.825 4.85 R378 6.15 4.65 R453 4.525 3.4 C328 4.775 3.325 D308 8.5 3.775 R311 2.525 4.425 R379 7.525 3.975 R454 7.325 1.95 C329 2.0 2.95 D309 10.85 3.6 R312 0.75 3.0 R380 7.825 3.425 R455 5.125 2.175 C330 2.5 2.225 D310 10.67 3.6 R314 4.4 3.7 R381 5.0 4.15 R456 4.775 1.325 C331 5.1 1.975 D311 8.45 4.575 R315 6.4 3.525 R382 6.25 4.2 R457 6.525 0.825 C332 5.65 4.65 D312 3.3 3.275 R316 4.8 4.15 R383 7.625 3.525 R458 5.95 0.8 C333 5.725 0.55 D313 4.55 0.7 R317 1.625 3.975 R385 7.725 3.975 Rt301 1.002 4.944 C334 4.6 2.0 D314 6.425 0.6 R318 3.225 1.225 R386 5.85 4.2 S301 9.757 0.326 C335 6.325 1.65 D315 2.25 2.35 R319 7.525 2.975 R387 6.55 4.65 S302 1.119 3.41 C336 1.9 2.55 D316 5.05 3.1 R320 8.75 1.25 R388 4.125 0.7 T301 3.225 2.325 C337 1.55 1.57 D317 2.85 1.625 R321 7.025 3.525 R389 5.375 0.7 U302 5.225 4.625 C338 1.65 1.575 D318 1.9 2.45 R322 0.6 3.55 R390 7.725 2.975 U304 8.3 3.325 C339 2.05 1.4 D319 4.6 4.05 R323 3.225 0.925 R391 6.65 4.2 U305 8.45 1.15 C340 10.67 4.825 D321 2.775 0.825 R324 4.95 0.25 R392 5.95 4.65 U306 7.35 2.375 C341 8.15 4.125 D322 4.45 0.35 R325 3.375 2.1 R393 2.625 0.875 U307 8.15 2.475 C342 9.42 5.39 D323 2.525 0.475 R326 7.95 1.35 R394 3.475 1.65 U308 4.725 3.975 C344 10.57 5.275 D325 2.175 0.575 R327 2.075 0.5 R395 3.425 0.875 U309 2.125 4.3 C345 6.175 1.8 D326 3.925 0.725 R328 1.75 0.95 R396 0.75 2.8 U311 5.65 3.975 C346 6.4 3.425 D327 5.375 0.45 R329 2.625 0.775 R397 6.225 0.25 U312 7.125 3.975 C347 4.75 0.7 D328 3.625 0.25 R330 2.4 1.825 R398 6.525 3.975 U315 7.45 4.5 C348 0.4 4.1 D329 2.0 2.85 R331 2.95 2.8 R401 6.35 4.65 U316 3.825 1.175 C349 6.925 3.975 D330 8.05 5.275 R332 2.85 2.425 R402 2.85 3.975 U318 6.425 2.1 C350 4.85 0.7 D334 6.225 3.15 R333 2.25 2.0 R403 6.025 2.8 U319 5.2 1.975 C352 6.85 3.325 D335 6.925 2.8 R334 6.825 2.725 R404 5.425 3.975 U320 6.425 3.1 C353 5.1 4.6 D336 7.625 4.95 R335 6.05 4.65 R405 6.45 4.2 U321 5.825 0.55 C354 9.8 3.475 D337 7.075 5.05 R336 3.225 0.725 R406 3.525 0.7 U322 2.2 1.875 C355 10.05 2.8 D338 7.55 2.45 R337 5.575 2.9 R407 6.625 3.525 U324 2.475 1.4 C356 5.575 2.075 D339 4.7 4.5 R338 1.95 1.4 R408 2.625 0.675 U325 3.9 2.05 C357 7.35 4.2 D340 2.025 4.35 R339 1.375 0.225 R409 3.175 1.65 U326 6.625 1.175 C358 7.025 0.875 D341 4.6 4.5 R340 2.35 2.75 R410 3.075 2.1 U327 6.95 4.55 C359 4.45 1.325 F301 0.964 2.379 R341 5.325 3.975 R411 2.35 2.65 U328 5.15 1.125 C360 7.85 4.575 F302 6.05 3.975 R342 1.325 4.425 R412 3.275 1.65 Vr301 2.5 2.125 C361 7.125 1.325 F303 10.35 4.15 R343 1.225 4.425 R413 8.05 4.125 Vr302 2.85 1.925 C362 5.0 1.625 F304 5.225 3.525 R344 6.925 2.725 R414 8.575 2.35 Vr303 7.725 4.95 C363 4.13 2.125 F305 10.42 2.3 R345 2.625 0.975 R415 2.75 3.325 Vr304 7.525 4.95 C364 1.425 3.975 F306 10.45 4.15 R346 3.225 1.125 R416 7.95 4.575 Vr305 8.1 2.025 C365 1.825 3.975 F307 7.475 0.35 R347 7.625 2.975 R418 3.95 3.15 C366 3.725 0.7 F308 10.02 4.85 R348 1.8 2.1 R419 7.95 3.175 C367 2.95 3.975 F309 4.1 3.525 R349 3.825 0.7 R421 3.95 3.675 C368 1.925 4.425 F310 9.925 4.85 R350 4.65 0.7 R422 7.475 2.35 C369 10.8 1.075 R351 7.025 2.725 R423 7.925 2.65

Figure 6-1. A1 Board Component Locations

Figure 6-2. A4 Board Component Locations

Figure 6-3. A1 Board schematic (sheet 1)

Figure 6-3. A1 Board schematic (sheet 2)

Figure 6-3. A1 Board schematic (sheet 3)

Index

—+—

+OUT, 47 +sense, 47

—A—

A1 board removal, 44 A1 Main board, 50 A2 board removal, 43 A2 Interface Board, 48 A2S201, 50 A3 board removal, 44 A3 Front Panel, 48 ADC, 48

—B—

bias voltages, 37, 38

—C—

cal denied, 40 calibration, 40 calibration - post repair, 40 CC, 37 CC line regulation, 17 CC load effect, 18 CC load regulation, 17 CC loop, 52 CC noise, 19 CC- operation, 17 CC source effect, 18 CC_Detect*, 48, 52 CC_Prog, 50, 52 clear password, 40 component locations

A1, 66

A4, 68

constant current tests, 16 constant voltage tests, 14 Control, 50, 52 copyrights, 5 cover removal, 43 current monitoring resistor, 13 current sink, 17 CV, 37 CV load effect, 14 CV loop, 52 CV Noise, 15 CV source effect, 15 CV/CC control, 50, 52 CV_Detect*, 48, 52 CV_Prog, 50, 52

—D—

DAC, 48 disable protection, 39 disassembly - tools, 42 disassembly procedure, 42 downprogramming, 50, 52 DP_Control, 50

—E—

EEPROM, 50 electronic load, 13 electrostatic discharge, 10 error codes, 36

—F—

F309, 50 fan speed, 39 Fan_Prog, 50, 52 firmware revisions, 10, 41 FLT, 47 front panel removal, 43 Fuse, 50

—G—

GPIB, 47

—H—

hazardous voltages, 9 history, 5 HS_Therm, 50

—I—

identification, 5 IDN? query, 41 Imon_H, 50 IMon_H, 52 Imon_L, 50 Imon_P, 50 INH, 47 inhibit calibration, 40 initialization, 41 interface signals, 47

—J—

J307 voltages, 38

—L—

line voltage wiring, 44

Index

—M—

manual revisions, 10

—N—

notice, 5

—O—

-OUT, 47 out of range, 40 OV_Detect*, 48, 52 OV_Prog, 50 OV_SCR*, 48, 52

—P—

PARD, 15, 19 password, 40 performance test form, 19 performance tests, 13 PM_Inhibit, 52 power-on self-test, 36 primary interface, 48 printing, 5 programming, 13 protection, 39

—R—

readback accuracy, 14 reference voltages, 37, 38 replaceable parts - A1 board, 58 replaceable parts - binding posts, 64 replaceable parts - chassis, 55 revisions, 10

RmHi, 52 RmLo, 52

ROM upgrade, 41 RPG, 48 RS-232, 47

safety summary, 3 schematic

A1, 69, 70, 71

A4, 68

schematic notes, 65 SCR, 52 secondary interface, 48 self-test, 36

-sense, 47 sense switch, 52 serial number, 5 series regulator, 50 shunt clamp, 52 status annunciators, 37

—T—

Temp_Amb, 50 test equipment, 11 test setup, 12 trademarks, 5 transformer removal, 44 transient recovery, 16 troubleshooting - bias and reference supplies, 37, 38 troubleshooting - equipment, 22 troubleshooting - flowcharts, 22 troubleshooting - introduction, 21 troubleshooting - overall, 22 troubleshooting - status annunciators, 37

—U—

UNR, 37

—V—

verification tests, 13 VMon, 50, 52 voltage programming, 14

safety considerations, 9

—S—

—W—

warranty, 2

Agilent 66312A Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Warranty Information

Safety Summary

Notice

Printing History

Instrument Identification

Table of Contents

Introduction

Organization

Safety Considerations

Related Documents

Revisions

Manual Revisions

Firmware Revisions

Electrostatic Discharge

Verification and Performance Tests

Introduction

Test Equipment Required

Measurement Techniques

Test Setup

Electronic Load

Current-Monitoring Resistor

Operation Verification Tests

Performance Tests

Programming

Constant Voltage (CV) Tests

CV Setup

Voltage Programming and Readback Accuracy

CV Load Effect

CV Source Effect

CV Noise (PARD)

Transient Recovery Time

Constant Current (CC) Tests

CC Setup

Current Programming and Readback Accuracy

Current Sink (-CC) Operation

Low Range Current Readback Accuracy

CC Load and Line Regulation

CC Load Effect

CC Source Effect

CC Noise (PARD)

Performance Test Equipment Form

Performance Test Record Form

Troubleshooting

Introduction

Test Equipment Required

Overall Troubleshooting

Flow Charts

Specific Troubleshooting Procedures

Power-on Self-test Failures

CV/CC Status Annunciators Troubleshooting

Bias and Reference Supplies

J307 Voltage Measurements

Manual Fan Speed Control

Disabling Protection Features

Post-repair Calibration

Inhibit Calibration Switch

Calibration Password

Initialization

ROM Upgrade

Identifying the Firmware

Upgrade Procedure

Disassembly Procedures

List of Required Tools

Cover, Removal and Replacement

A2 Interface Board, Removal and Replacement

Front Panel Assembly, Removal and Replacement

A3 Front Panel Board, Removal and Replacement

A1 Main Control Board

T1 Power Transformer, Removal and Replacement

Line Voltage Wiring

Principles of Operation

Introduction

I/O Interface Signals

A3 Front Panel Circuits

A2 Interface Circuits

Primary Interface