Agilent 66111A Service Manual

Service Manual

For Agilent Technologies

Model 66111A, 66311A/B/D, 66309B/D

Mobile Communications DC Source

For instruments with Serial Numbers: 66111A: US38460101 and up (through-hole) 66311A: US38180101 through US38180408 (through-hole) 66311B: US38440101 through US38442274 (through-hole) 66311B: US38442500 and up (surface-mount) 66311D: US39010101 and up (surface mount 66309B: US39050101 and up (surface mount) 66309D: US39070101 and up (surface mount)

Agilent Part No. 5964-8176 Printed in U.S.A. Microfiche No 5964-8177 January, 2001

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 comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design, manufacture, and intended use of the instrument. Agilent Technologies assumes no liability for the customer’s failure to comply with these 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

Verify that the product is set to match the available line voltage, the correct line fuse is installed, and all safety precautions (see 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.

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 a Agilent Technologies 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 shall not be liable for errors contained herein or for incidental or consequential 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 .

Agilent Technologies

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.

Edition 1............................................................................................................................................ December 1999

Update 1............................................................................................................................................ January 2001

Instrument Identification

The dc source is identified by a unique, two-part serial number, such as, US39450101. The items in this serial number are explained as follows:

US39450101

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, 39=1999. The third and fourth digits specify the week of the year (45 = the forty-fifth week).

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

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

1 - INTRODUCTION 9

Organization 9 Safety Considerations 9 Related Documents 9 Revisions 10

Manual Revisions 10 Firmware Revisions 10

Electrostatic Discharge 10

2 - VERIFICATION AND PERFORMANCE TESTS 11

Introduction 11 Test Equipment Required 11 Measurement Techniques 12

Test Setup 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 14 CV Noise (PARD) 15 Transient Recovery Time 15

Constant Current (CC) Tests 16

CC Setup 16 Current Programming and Readback Accuracy 16 Current Sink (-CC) Opera tion 16 Low Range Current Readback Accuracy 17 CC Load and Line Regulatio n 17 CC Load Effect 18 CC Source Effect 18 CC Noise (PARD) 18

Performance Test Equipment Form 19 Performance Test Record Form 20

3 - TROUBLESHOOTING 23

Introduction 23 Test Equipment Required 24 Overall Troubleshooting 24

Flow Charts 24

Specific Troubleshooting Procedures 29

Power-on Self-test Failures 29 Bias and Reference Supplies 30 CV/CC Status Annunciators Troubleshooting 30 J307 Voltage Measurements 30 Manual Fan Speed Co ntrol 32 Disabling Protection Features 32

Post-repair Calibration 32

Calibration Password 32 Inhibit Calibration Switch 33

Initialization 33 ROM Upgrade 33

Identifying the Firmware 33 Upgrade Procedure 34

Disassembly Procedures 35

List of Required Tools 35 Cover, Removal and Replacement 37 A2 Interface Board, Removal and Replacement 37 Front Panel Assembly, Removal and Replacement 37 A3 Front Panel Board, Removal and Replacement 38 A6 Option 521 Relay Board (not on all models) 38 A7 DVM Board (not on all models) 38 A1 Main Control Board 38 T1 Power Transformer, Removal and Replacement 39

4 - PRINCIPLES OF OPERATION 41

Introduction 41 I/O Interface Signals 41 A3 Front Panel Circuits 42 A2 Interface Circuits 42

Primary Interface 42 Secondary Interface 42

A1 Main Board Circuits 43

Power Circuits 43 Control Circuits 44 Output 2 45

A5 DVM Circuits 46 A6 Option 521 Relay Circuits 46

5 - REPLACEABLE PARTS LIST 47

Introduction 47

6 - DIAGRAMS 53

Introduction 53

INDEX 59

Introduction

Organization

This manual contains information for troubleshooting and repairing Agilent 66111A, 66311A, 66311B, 66311D, 66309B and 66309D Mobile Communications DC Sources. Hereafter all models will be referred to as the dc source.

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 source chassis.

This dc source 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 source 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 sources 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 source, 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 may be different from that described here. Such differences, if any, will be covered in a 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 source using the GPIB *IDN?’ query command (see chapter 3, ROM Upgrade).

Electrostatic Discharge

CAUTION: The dc source 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 source, observe all standard, antistatic work practices. These include, but are not limited to: ñ Working at a static-free station such as a table covered with static-dissipative laminate or with a conductive

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

ñ Using a conductive wrist strap, such as P/N 9300-0969 or 9300-0970. ñ Grounding all metal equipment at the station to a single common ground. ñ Connecting low-impedance test equipment to static-sensitive components only when those

components have power applied to them.

ñ Removing power from the dc source before removing or installing printed circuit boards.

Verification and Performance Tests

Introduction

This document contains test procedures to verify that the dc source is operating no rmally and is within published specifications. There are three types of tests as follows:

Built-in Self Tests

Operation Verification

Performance Tests

NOTE: The dc source 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 dc source is turned on, check most of the digital circuits and the programming and readback DACs.

These tests verify that the dc source 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 User’s Guide.

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.

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

Type Specifications Recommended Model

Digital Voltmeter Resolution: 10 nV @ 1V

Readout: 8 1/2 digits Accuracy: 20 ppm

Current Monitor Resistor

DC Power Supply

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

15 A (0.1 ohm) 0.04%, TC=5ppm/°C for power supplies up to 15 A output

8V @ 5A (for current sink veri fic ation/calibration) 25 V source (for DVM verification/calibration)

Agilent 3458A or equivalent

Guildline 9230/15

Agilent 6611C, 6631B 6631C, or 6633B

GPIB Controller Full GPIB capabilities (only required if you are

calibrating the unit over the GPIB)

Load Resistor

(3 W min. TC=20ppm/°C)

Oscilloscope Sensitivity: 1 mV

400Ω (verification) 800Ω (calibration)

Bandwidth Limit: 20 MHz Probe: 1:1 with RF tip

HP Series 200/300 or equivalent

p/n 0811-0942 p/n 0811-0600

Agilent 54504A or equivalent

2 - Verification and Performance Tests

RC network (for transient response test)

Capacitor: fixed film 25µF, 50V Resistor: 0.25Ω, 1W

RMS Voltmeter True RMS

Kit p/n 6950L#T03

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

All tests are performed at the rear terminals of the supply as shown in Figure 2-1. Measure the dc voltage directly at the +S and -S terminals. Connect the output for remote sensing. Use adequate wire gauge for the load leads.

++S

SENSE

Load

resistor

400 ohm

Local Remote

Set to Remote

(through-hole

units only)

SENSE

Local Remote

Set to Remote

(through-hole

units only)

DVM, Scope, or RMS voltmeter

(for CV tests)

DVM or

RMS voltmeter (for CC tests)

Notes:

Use dc supply with same polarity

connections for - CC tests.

Replace electronic load with resistors for CC noise test.

NOTE: Connector

is removable

Current monitor

-S -

++S

50VDC MAX TO

-+ Electronic

Load

(see note)

-S - +

SENSE

Local Remote

Set to Remote

(through-hole

units only)

Local Remote

Ammeter

Oscilloscope

NOTE: Connector

is removable

-S

50VDC MAX TO

External

DC supply

-S -

50VDC MAX TO

Ammeter

Set to Remote

Load

resistor 400 ohm

(through-hole

units only)

-+ Electronic

Load

Figure 2-1. Test setup Agilent 66111A, 66311B/D, 66309B/D (surface-mount units)

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 dc source may have to be taken into account. "Wait" statements can be used in the test program if the test system is faster than the dc source.

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 current-monitoring 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 turn-on and

checkout procedures given in the User’s Guide.

Performance Tests

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

User’s Guide, 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 User’s Guide. 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 an GPIB controller when performing the tests. The test procedures are written assuming that you know how to program the supply either; remotely from an 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.

Table 2-2. Programming and Output Values

Agilent

Model

66111A 15 15.535 3 3.0712 - 2A 22.0

66311A/B/D 15 15.535 3 3.0712 - 2A 22.0

66309B/D 15 15.535 3 3.0712 - 2A 22.0

Full scale

Voltage

Vmax Full Scale

Current

Imax Isink OV

Max

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 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 -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 (Imax in

Table 2-2) 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 card for the appropriate model under Voltage Programming and Readback @ 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 (see Table 2-2) . 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 card for the appropriate model under Voltage Programming and

Readback @ 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 (Imax) and the voltage to the

full-scale value in Table 2-2. c. Adjust the load for the full-scale current in Table 2-2 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 card

for the appropriate model under CV Load Effect.

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.

Verification and Performance Tests -2

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

to the full-scale value in Table 2-2. d. Adjust the load for the full-scale current value in Table 2-2 as indicated on the front panel display. The CV

annunciator on the front pa nel must be on. If it is not, adjust the loa d so that the output current d rops 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 card 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 coup led) between the

(+) and the (-) terminals. Set the scope's bandwidth limit to 20 MHz and use an RF tip on the scope probe. b. Turn on the supply and program the current to the maximum programmable value (Imax) and the output voltage

to the full-scale value in Table 2-2. c. Adjust the load for the full-scale current value in Table –2 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 card 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 card for the appropriate model under CV Noise (PARD).

Transient Recovery Time

This test measures the time for the output voltage to recover to within the specified value following a change in the load current. The focus of the transient is on the initial dip below zero. To recover to within the 20mV band, the negative portion should be within 35 microseconds to meet the specification.

Figure 2-2. Transient Waveform

2 - Verification and Perform ance Tests

a. Turn off the supply and connect the output as in Figure 2-1d with the oscilloscope and the RC network across

the + and - load terminals. Connect everything at the load and keep the load leads as short as possible. To reduce

noise, twist the sense lead pair together. Also twist the load lead pair together. b. Turn on the supply and program the output current to the maximum programmable value (Imax) and the voltage

to the full-scale value in Table 2-2. Make sure that compensation is set to High capacitance mode. c. Set the load to the Constant Current mode and program the load current to 0.1 amps. d. Set the electronic load’s transient generator frequency to 220 Hz and its duty cycle to 50%. e. Program the load’s transient current level to 1.5 amps and turn the transient generator on. f. Set the oscilloscope for negative edge triggering and adjust it 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 35 microseconds. Record the

voltage at time “t” in the performance test record card under CV Transient Response.

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 dc source and connect the current monitoring resistor across the dc source output and the DVM

across the resistor. See "Current Monitoring Resistor" for connection information. b. Turn on the dc source and program the output voltage to 5 V and the current to 20mA (±1mA). The dc source’s

current detecto r must be set to DC and the pro gramming language mode to SCPI. See the specifications for high

range current readback in the User’s Guide if operating with the detector in ACDC or the language in

Compatability mode. 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 Current

Programming and Readback @ 0 Amps. d. Program the output current to the full-scale value in Table 2-2. 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 Current Programming and Readback @ Full Scale.

Current Sink (-CC) Operation

This test verifies current sink operation and readback. a. Turn off the dc source 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 power supply to 5 V and the current to the full scale current rating of the dc source as in Table 2-2. c. Turn on the dc source under test and program the output voltage to zero and the current to full scale as in Table

2-2. The current on the UUT display should be negative and decreases linearly from 2.8A @ 0V to 1.2 A @

15V. The sink current does not track the programmed current.

Verification and Performance Tests -2

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 card 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 and set the current range readback to Low or Auto. Program the output voltage to

zero and the current to the full scale value in Table 2-2. 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 card under 20mA Range

Current Readback Accuracy @ 0A. d. Program the output voltage to 8V and record the current reading on the DMM and the reading on the front

panel display. If the meter indicates overrange, lower the 8 volts slightly. The difference between the readings

should be within the limits specified in the performance test record card 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 8V and 1 amp. Then program the supply under test to zero volts

and 1 amp. If the meter indicates overrange, lower the voltage of the external supply slightly. The UUT display

should read approximately −20 mA. g. 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 card 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 dc source’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 . 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).

2 - Verification and Performance Tests

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 if it was set to low range readback in the previous test, set it back to high or auto.

Program the current to full scale and the output voltage to the maximum programmable voltage value (Vmax) in

Table 2-2. c. Adjust the load in the CV mode for the UUT full scale voltage in Table 2-2 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 card 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 (Vmax) in Table 2-2. 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.

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 50W, 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.

Verification and Performance Tests -2

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 (Vmax) in Table 2-2. 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 current 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:_________________________ ____________________________________ 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

_________________ _________________ _________________ _________________ _________________ _________________ _________________ _________________ _________________ _________________ _________________ _________________ _________________ _________________ _________________ _________________ _________________ _________________ _________________ _________________ _________________

Report Number ________________________

2 - Verification and Performance Tests

Performance Test Record Form

Model Agilent 66111A Report No _______________ Date __________________

Test Description Minimum

Specs.

Constant Voltage Tests

Voltage Programming and Readback

Low Voltage (0V) Vout Front Panel Display Readback High Voltage (Full Scale) Vout Front Panel Display Readback

Load Effect Source Effect PARD (Ripple and Noise)

RMS peak-to-peak

Transient Response

Voltage in 35 µs

Constant Current Tests

High Range Current Programming and Readback

Low current (0A) Iout High Current (Full Scale) Front Panel Display Readback @ Iout

−

10 mV

Vout − 5 mV

14.982 V

Vout − 9.5mV

−

2.0mV

−

0.5mV

−

0 mV

−

0 mV

−

20 mV

−

1.33 mA

2.9972 A

Iout − 15mA

Results* Maximum

Specs.

__________ __________ __________ __________

__________ __________ + 0.5 mV

__________ __________

__________ + 20 mV 3 mV

__________ __________ __________

+ 10 mV

Vout + 5 mV

15.018 V

Vout + 9.5 mV

+ 2.0mV

+ 1 mV + 6 mV

+ 1.33 mA

3.0028 A

Iout + 15mA

Measurement

Uncertainty

1.6 µV

1.6 µV 335 µV 335 µV

20 µV 20 µV

50 µV

872 µV

15.2 µA 252 µA 252 µA

Current Sink

Low Current Readback High Current (-2A @ 7.5V) Readback

Load Effect Source Effect PARD (Current Ripple and Noise)

RMS

Isink − 2.5 µA

Isink − 13 mA

−

0.75mA

−

0.75mA

− 2.0 mA

__________ __________

__________ + 0.75mA __________

__________ + 2.0 mA

Isink + 2.5 µA Isink + 13 mA

+ 0.75mA

0.1 µA

200 µA

1.6 µA

200 µA

Verification and Performance Tests -2

Model Agilent 66311B/D Model Agilent 66309B/D Test Description Minimum

Constant Voltage Tests

Voltage Programming and Readback

Low Voltage (0V) Vout Front Panel Display Readback High Voltage (Full Scale) Vout Front Panel Display Readback

Load Effect Source Effect PARD (Ripple and Noise)

RMS peak-to-peak

Transient Response (only applies to the negative portion of transient waveform)

Voltage in 35 µs

Constant Current Tests

High Range Current Programming and Readback

Low current (0A) Iout High Current (Full Scale) Front Panel Display Readback @ Iout

Current Sink

Low Current Readback High Current (-2A @ 7.5V) Readback

20 mA Range Current Readback

Front Panel Display Readback @ 0 A Front Panel Display Readback @ + 20 mA Front Panel Display Readback @ − 20 mA

Load Effect Source Effect PARD (Current Ripple and Noise)

RMS

Report No _______________ Date __________________

Specs.

− 10 mV

Vout − 5 mV

14.982 V

Vout − 9.5mV

− 2.0mV

− 0.5mV

− 0 mV

− 20 mV

− 1.33 mA

2.9972 A

Iout − 6.5mA

Isink − 2.5 µA Isink − 5.1 mA

− 2.5 µA

Iout − 22.5 µA Iout − 22.5 µA

− 0.75mA

− 2.0 mA

Results* Maximum

Specs.

__________ __________ __________ __________

__________ __________ + 0.5 mV

__________ __________

__________ + 20 mV 3 mV

__________ __________ __________

__________ __________

__________ __________ __________

__________ + 0.75mA __________

__________ + 2.0 mA

+ 10 mV

Vout + 5 mV

15.018 V

Vout + 9.5 mV

+ 2.0mV

+ 1 mV + 6 mV

+ 1.33 mA

3.0028 A

Iout + 6.5mA

Isink + 2.5 µA

Isink + 5.1 mA

+ 2.5 µA

Iout + 22.5 µA Iout + 22.5 µA

+ 0.75mA

Measurement

Uncertainty

1.6 µV

1.6 µV 335 µV 335 µV

20 µV 20 µV

50 µV

872 µV

15.2 µA 252 µA 252 µA

0.1 µA

200 µA

0.1 µA

1.7 µA

1.6 µA

200 µA

2 - Verification and Performance Tests

Model 66311D/66309D Output 2 Report No _______________ Date __________________

Test Description Minimum

Specs.

Constant Voltage Tests

Voltage Programming and Readback

Output 2 Low Voltage Output 2 Front Panel Display Readback Output 2 High Voltage Output 2 Front Panel Display Readback

Load Effect Source Effect

−

40 mV

V2 lo − 15 mV

11.936 V

V2 hi − 39 mV Vout − 1.6 mV

Vout − 0.5 mV

PARD (Ripple and Noise)

RMS (with phone capacitance <6µF) Peak-to-Peak

Transient Response

Time in <400 µs

Vout − 1 mV Vout − 6 mV

Vout − 20 mV

Constant Current Tests

High Range Current Programming and Readback

Output 2 Low Current Output 2 High Current Output 2 Front Panel Display Readback

Current Sink (-0.032A @ 7.5V) Readback

−

4.5 mA

1.492 A

I2 hi − 6 mA

−

25 mA

Results* Maximum

Specs.

__________ __________ __________ __________

__________ __________

__________

__________ __________ __________

+ 40 mV

Vout + 15 mV

12.064 V

Vout + 39 mV Vout + 1.6mV

Vout + 0.5 mV

Vout + 1 mV Vout + 6 mV

Vout + 20 mV

+ 4.5 mA

1.508 A

I2 hi + 6 mA

__________ + 39 mA

Measurement

Uncertainty

1.6 µV

1.6 µV 335 µV 335 µV

20 µV 20 µV

50 µV

872 µV

3 mV

15.2 µA

15.2 µA 252 µA

PARD (Current Ripple and Noise)

RMS

Load Effect Source Effect

Following a 0.75A to 1.5A load change

Iout −2.0 mA

Iout −0.375mA

Iout −0.25mA

__________ __________ __________

Iout + 2.0 mA

Iout +0.375mA

Iout + 0.25mA

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 source. Before attempting to troubleshoot the dc source, 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 source. Troubleshooting procedures are provided to isolate a problem to one of the circuit boards. Figure 3-2 shows the location of the circuit boards and other major components of the unit. 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 an assembly is defective, replace it and then conduct the verification test given in Chapter 2.

NOTE: When either the A1 Control Board or the A2 Interface Board is 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 board level replaceable parts for the dc source. Chapter 6 contains block diagrams, 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 dc source. 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 (60V) or 6063B

Ammeter/Current Shunt

To measure output current Guildline 9230/15

HP Series 200/300

(240V)

Overall Troubleshooting

Overall troubleshooting procedures for the dc source 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 1-4. The flow charts make reference to the test points listed in Chapter 6. The circuit locations of the test points are shown on the component location diagrams in Chapter

Turn on unit and observe display. All segments and annunciators should light. The address appears next. After self test, the unit should either display an error message or go to the metering mode.

Check Bias voltages

(see Table 3-3)

Troubleshooting - 3

Bias voltages OK?

Yes

Display on?

Fan on?

Yes

Error Message?

Protect

annunciator

on?

AC line OK?

Xfmr inputs OK?

Replace A1

Go to Error Message

Yes

Table 3-2.

Yes

RI?

OV?

Check main fuse F301.

If OK, replace T1

+5V @ A2J211-1

(to chassis)?

Yes

A2J211-5 low

(no pulses)?

Yes

Replace A2

Check for OV setting

Yes

< Voltage setting.

If OK, replace A1

Check A1F304.

Check cable

W12 (power

cable from A1

to A2 board)

Replace A3

No Output?

Go to Sheet 2

Check that OCP is not

OC?

Yes

enabled. If OK,

replace A1

For OT check fan. If

OK, replace A1

Yes

Check A1 F309 output fuse.

Check Opt. 521 board cables.

If OK, replace A1

Figure 3-1 Sheet 1. Troubleshooting Flowchart

3 - Troubleshooting

From Sheet 1

Enable output and

program voltage and

current full scale with

no load. Measure

output voltage.

Unit OV’s?

Check to insure OV

setting is not less than

Yes

the voltage setting.

If not, replace A1.

Output out of spec

but close?

Output OK but

meter wrong?

Output voltage

> 10% error?

Program the OV 2 volts

lower than the output

voltage.

Yes

Calibrate voltage

Calibrate voltage. If still

Yes

wrong or will not

calibrate, replace A2

CV_Prog &

Yes Yes

CC_Prog OK?

(see Table 3-4)

Replace A2

Check cable W12,

If OK, replace A1

Unit OV’s?

Go to Sheet 3

Program OV to

full scale

OV_Prog OK?

(see Table 3-4)

NoYes

Yes

Replace A2

Figure 3-1 Sheet 2. Troubleshooting Flowchart

Calibrate OV. If OV is still not

functioning properly check

W12. If OK replace A1.

From Sheet 2

Program current to full scale, voltage to Vmax

and load to the power

supply’s rated current.

Supply should be in CC.

Troubleshooting - 3

Output out of spec

but close?

Output OK but

meter wrong?

Will not go into CC

or error > 10%

Turn on OCP and

insure Protect trips.

Yes

Calibrate unit

Calibrate current. If still

Yes

wrong or will not

calibrate, replace A2

Yes

CC_Prog OK ? (see Table 3-4)

Replace A2

Yes

Replace A1

Prot trips?

Yes

CC_detect* low?

(see Table 3-4)

Yes

Replace A2

Goto Sheet 4

Figure 3-1 Sheet 3. Troubleshooting Flowchart

Check cable W12. If

OK, replace A1

3 - Troubleshooting

From Sheet 3

Connect controller to

the HPIB port and send

commands to set the

output voltage and

current and readback

the output.

Accepts and reads

back?

Yes

Run the Performance

Test in Chapter 2.

Passes test?

Yes

Short RI terminals on

rear of supply and

insure output disables

and Prot annunciator

comes on.

Remote Inhibit

OK?

Replace A2

Regulation, Transient

Response and ripple

problems are generally

caused by A1

Replace A2

Yes

There is either no fault

with the power supply

or the problem is not

covered by this

procedure.

Figure 3-1 Sheet 4. Troubleshooting Flowchart

Troubleshooting - 3

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 dc source 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

3 - Troubleshooting

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 (R899 on surface-mount units; R431-4 on through-hole units) 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 A1 R431-4 (through-hole)

A1 R899 (surface-mount)

+15V secondary A1 R419 A1 R431-4 (through-hole)

A1 R899 (surface-mount)

-15V secondary A1 R422 A1 R431-4 (through-hole) A1 R899 (surface-mount)

+15V secondary gated A1 F304 A1 R431-4 (through-hole)

A1 R899 (surface-mount)

-15V secondary gated A1 F302 A1 R431-4 (through-hole) A1 R899 (surface-mount)

+Rail Output 1 +Rail Output 2 +2.5V reference A1 J307-6 (through-hole)

+5V bias Output 2 A1 UB771-1 R885 +5V +/- 0.2V

-5V bias Output 2 A1 UB760-16 R885 -5V +/- 0.2V

+12V bias Output 2 A1 UB760-15 R885 +12V +/- 0.5V

Measured at nominal ac input line voltage

Note1

Heat Sink - Output ~25V with no load +/-10% Drain/Case Q762 - Output 2 ~20V with no load +/-10%

A1 R431-4 (through-hole)

A1 +C753 (surface-mount)

A1 R899 (surface-mount)

+5V +/- 0.2V

+15V +/- 0.6V

-15V +/- 0.6V

+14.2V +/- 5%

-14.2V +/- 5%

+2.5V +/- 5%

CV/CC Status Annunciators Troubleshooting

The CV/CC annunciators are particularly helpful when troubleshooting a unit with no output voltage or current. If the unit has passed self test the programming DAC circuits on the A2 circuit board are probably working properly. If either the CV or CC annunciators is on then the problem is in either the CV or CC control circuits located on the A1 Main board. If UNR is indicated then neither the voltage nor the current circuits are in control and the problem would be in the main power transformer or the driver or output regulator stages circuits, also on A1 but after the gating diodes.

J307 Voltage Measurements

Cable W8 connects J307 of the A1 Main Board Assembly to J207 of 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. Note that Agilent 66311B units with through-hole boards (these are the units that have the external remote sense switch on the rear panel) have a 28-pin connector. All other units with surface-mount boards use the 30-pin connector.

Troubleshooting - 3

Table 3-4. Voltage Measurements at J207 (A2 Interface to A1 Main board)

A1J207

(30-pin)

1 Status_Ctrl_1 (30-pin only) 2 1 PM_Inhibit 0 (Enabled) 0 (Enabled) 3 2 OV_SCR +5 +5 4 3 OV_Prog +3.9 +3.9 5 4 Fan_Prog +2.8 +3.8 6 5 OV_Detect +5 +5 7 6 Burst (30-pin)

8 7 Range_Cap (30-pin only)

9 8 CV_Prog_2 (30-pin only) 10 9 C_Mux_Ctrl_2 (30-pin only) 11 10 +5Vs +5 +5 12 11 Common 0 0 13 12 Common 0 0 14 13 +15Vs +15 +15 15 14 -15Vs -15 -15 16 15 HS_Therm +2.5 (@25C) +2.5 (@25C) 17 16 CC_Prog_2 (30-pin)

18 17 IMon_H 0 +3.5 19 18 Rdbk_16bit (30-pin)

20 19 IMon_P 0 0 21 20 VMon +4.8 +4.8 22 21 Common 0 0 23 22 Common 0 0 24 23 Common 0 0 25 24 CV_Prog -4.8 -4.8 26 25 CC_Prog -4.8 -4.8 27 26 C_Mux_Ctrl_1 (30-pin)

28 27 Common 29 28 Status_Detect (30-pin)

30 Status_Ctrl_2 (30-pin only)

A1J207

(28-pin)

Signal Name CV Mode

Full Scale Voltage

No Load

2.5V reference (28-pin) 2.5 2.5

Fuse (28-pin)

IMon_L (28-pin) 0 +14.7

CC_Detect (28-pin) +5

CV_Detect (28-pin) 0 +5

+2.4

CC Mode

Full Scale Current

Full Load

+2.6

3 - Troubleshooting

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 turn-on 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

The dc source’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. The overvoltage protection function is not disabled by this procedure. 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"

Post-repair Calibration

Calibration is required annually and whenever certain components are replaced. If either A1 or A2 are replaced, the supply must be re-calibrated as described in Appendix B of the User’s Guide.

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

Calibration Password

In order to enter the calibration mode, you must use the correct password as described in Appendix B of the User’s Guide. 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

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 dc source 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 two 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

Initialization

The dc source’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 dc source:

a. Enable the Calibration mode by pressing "Shift", then "Cal", and then "Enter". 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 dc source will go through the turn-on self test sequence and return to the dc source metering mode. 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

There are two ways to identify the firmware of the unit, either from the front panel of the unit or over the GPIB. To display the firmware revision from the front panel of the unit,

a. Press the "Address" key. b. Using the Up/Down annunciator keys, scroll to ROM: <A.xx.xx>

3 - Troubleshooting

To identify the firmware revision over the GPIB bus, use the *IDN? query . The query will read back the revisions of the Primary Interface ROM (U205) located on the A2 Interface board. The manufacturer and model number of the unit 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: "HEWLETT-PACKARD,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

CAUTION: The dc source 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 source, observe all standard, antistatic work practices (see chapter 1). a. Under the Disassembly Procedures, in the section titled "A2 Interface Board, Removal and Replacement"

perform steps a. through f.

b. The board is now in a good position to replace the ROM. Use a chip removal tool (PLCC SMT Removal

Tool, p/n 5041-2553 or equivalent).

c. Carefully pull the U205 chip out of its socket using the access slots located in the two diagonal corners of the

chip socket.

d. To insert the new chip, place it over the chip socket. Face the bevel (or the dot on the chip ) toward the back

of the board, away from the GPIB connector. Push the chip down into the socket.

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

See "Initialization".

J206

J211J210

DSP

XILINX

U245

U205

A.0x.0x

U204

S201

HPIB

RS232

J203

Figure 3-2. Firmware component Locations

Troubleshooting - 3

Disassembly Procedures

The following paragraphs provide instructions on how to disassemble various components of the dc source. Once disassembled, the components can be reassembled by performing the disassembly instructions in reverse order.

Figure 3-3 shows the location of the major components of the unit. Note that not all boards are included with every model. Figure 3-4 shows the location of the cables that interconnect all of the boards. This figure shows only the boards, not the chassis of the unit.

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.

DVM board

Interface board

Option 521 relay board

Transformer (T1)

Figure 3-3. Component Location

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,

8 mm for toggle switch located on the back of Agilent 66311A and earlier 66311B units d. Long nose pliers. e. Antistatic wrist discharge strap.

Fan (B1)

Main board

Front panel/display board

3 - Troubleshooting

A3 FRONT PANEL

BOARD

FRONT OF UNIT

blue strip faces forward

TRANSFORMER

A1 MAIN BOARD

To transformer

(see Fig. 3-6)

W4 W3 W12 W2

J306

J304

J206

FAN

HEATSINK

blue strips

face up

blue strip

faces forward

blue strips face back

J211

W10

J623 J621

JB760

J314

J210

To transformer

(see Fig. 3-6)

J305

J800

J303J804

J307

J203

A2 INTERFACE BOARD

(shown flipped over with

component side up)

blue strip faces down

blue strips face back

A6 OPTION 521 RELAY BOARD

OUTPUT

CAP

J320

A5 DVM BOARD

BACK OF UNIT

Figure 3-4. Cable Locations

W13

NOTE: If relay board is not installed, cable W9 connects J210 to J804.

J620

W11

blue strip faces up

Troubleshooting - 3

Cover, Removal and Replacement

a. Using a T15 Torx screwdriver, unscrew the two captive screws that hold the rear bezel on the unit. b. Remove the two screws from the bottom of the case. c. Slide the cover back until it clears the rear of the dc source.

A2 Interface Board, Removal and Replacement

To remove the Interface Board, proceed as follows: a. Remove the cover of the dc source as described under, "Cover Removal and Replacement." b. Remove the two 7 mm and two 3/16 inch hex screws that hold the GPIB and RS-232 connectors in place. c. Slide the board forward, lift up on the side of the board closest to the heatsink, and slide the board out. d. Place a piece of non-conducting material (stiff paper or cardboard) on top of the transformer, flip the interface

board over, and place it on top of the non-conducting material. e. Unplug the 3-conductor cable from J206. Push down on the locking tab to release the connector. f. Unplug the ribbon cables. Note the position of the blue conductive side for reinstallation as shown in figure 3-4.

Release the cable by pulling out the end tabs as shown by the arrows in figure 3-5.

Figure 3-5. Cable Release

g. To reinstall the Interface board, perform steps a through e in reverse order.

Front Panel Assembly, Removal and Replacement

This procedure removes the front panel assembly from the dc source. a. Remove the cover as described earlier in, "Top Cover Removal and Replacement." b. Using a Torx T10 driver remove the screw from the right side of the supply that holds the front panel bracket to

the chassis. c. Locate and carefully peel off the left vinyl trim to gain access to the side screw that secures the front panel to the

chassis. Using a Torx T15 driver remove the screw located behind the vinyl trim. d. Place the power switch in the on position. Slide the switch extension forward as far as it can go and lift it up to

disengage from switch. Remove the extension from the unit. e. Rotate the front panel forward from right side to disengage the left mounting studs. Pull the entire panel forward.

Be careful not to break the Front panel ribbon cable. (To remove the ribbon cable you must first remove the

front panel board from the front panel assembly). 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. Once the board is free, you can remove the ribbon cable (see figure 3-5). d. To reinstall the Front Panel board, perform the above steps in reverse order.

A6 Option 521 Relay Board (not on all models)

a. Remove the top cover and flip over the A2 Interface board as previously described. b. Unplug the wiring harness from J620. Push down on the locking tab to release the connector. c. Unplug the ribbon cables. Note the position of the blue conductive side for reinstallation as shown in figure 3-3.

Release the cable by pulling out the end tabs as shown by the arrows in figure 3-5. d. Using a T15 Torx screwdriver, unscrew the two screws that attach the board to the chassis. e. To reinstall the Option 521 board, perform the above steps in reverse order.

A7 DVM Board (not on all models)

a. Remove the top cover and flip over the A2 Interface board as previously described. b. If your unit has an Option 521 board, remove the two screws that attach the board to the chassis and move the

board out of the way. c. Unplug the ribbon cable from the DVM board. Note the position of the blue conductive side for reinstallation as

shown in figure 3-4. Release the cable by pulling out the end tabs as shown by the arrows in figure 3-4. d. Using a #2 Pozidrive, unscrew the screw that attaches the board to the chassis. e. To reinstall the DVM board, perform the above steps in reverse order.

A1 Main Control Board

a. Remove the top cover and the A2 Interface board as previously described. b. Place the power switch in the on position. Slide the switch extension forward as far as it can go and lift it up to

disengage from switch. Remove the extension from the unit. c. If your unit has a DVM board or an Option 521 board, remove these boards as previously described. d. 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 when reinstalling these cables (see figure 3-4).

e. 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 T15 screw. f. Remove the three Torx T15 screws that secure the main control board to the chassis. g. Slide the main board towards the front panel to release it from chassis mounted standoff. Carefully lift the board

out of the chassis.

Troubleshooting - 3

T1 Power Transformer, Removal and Replacement

NOTE: The transformer primary connections are line voltage dependent. Figure 3-6 illustrates the primary

wiring configuration of the power transformer for various ac line voltages.

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 previously described. b. Remove the two Torx T10 screws securing the rear of the transformer bracket to the bottom of the chassis and

the two Torx T10 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.

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

for 110/120 Vac: 3.15 AT, 250V, p/n 2110-0638; for 220/230 Vac: 1.6 AT, 250V, p/n 2110-0773 The fuse is located on the A1 Main board assembly right behind the line switch.

grey

white/red/grey

orange

1 2

3 4

5 6

1 2

3 4

5 6 7

120 VAC

Top part of

transformer

Front of unit

100 VAC

Top part of

transformer

Front of unit

white/orange

white/black

white/brown

white/red

white/grey

white/violet white/yellow

white/red/grey

white/violet white/yellow

All voltages

Bottom part of

transformer

grey

orange

grey

orange

white/red/grey

1 2

3 4

5 6

1 2

3 4

5 6

white/red

red

black

white/black

220 VAC

Top part of

transformer

Front of unit

230 VAC

Top part of

transformer

Front of unit

orange (spare)

white/violet white/yellow

orange

(spare)

white/violet white/yellow

Front of unit

Figure 3-6. Transformer Wiring

Principles of Operation

Introduction

This section describes the different functional circuits used in the dc source. First, the I/O external signals that connect to the dc source are described. Next, the overall block diagrams for the dc source are described in detail. The simplified block diagrams found in chapter 6 show the major circuits on the dc source as well as the signals between circuits. They also show the reference designations of some of the components in the functional circuit.

I/O Interface Signals

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

Table 4-1. Dc source Interface signals

Connector Signal Description

Rear panel Output 1 screw terminals +OUT

-OUT + sense

- sense common

Rear panel Output 2 screw terminals (Agilent 66309B/D only)

Rear panel DVM screw terminals (Agilent 66311D/66309D only)

INH/FLT connector (units are shipped set to INH/FLT) pin 1

RS-232 connector XON-XOFF

+OUT 2

-OUT 2 + sense 2

- sense 2 common

+IN

-IN common

pin 2 pin 3 pin 4

RTS-CTS DTR-DSR NONE

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

-OUT sensing terminal connected to ground conductor

Positive dc output 2 voltage Negative dc voltage 2 (or return) +OUT sensing terminal

-OUT sensing terminal connected to ground conductor

Positive dc input Negative dc input connected to ground conductor

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

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 GPIB connector GPIB/IEEE 488 Interface to an external GPIB controller Ac input connector ac mains Can be 100Vac, 120Vac, 220Vac or 240Vac Input

4 - Principles of Operation

A3 Front Panel Circuits

As shown in Figure 6-3, the supply’s front panel assembly contains a circuit board, a keypad, a display, 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. The Agilent 66311A unit has a separate front panel binding post board. All circuit boards are available as assembly-level replaceable parts.

The A3 front panel board contains microprocessor circuits, which decode and execute all keypad and RPG commands that are transferred to the dc source output via the serial I/O port to the primary interface circuits on the A2 interface board. The front panel microprocessor circuits also process dc source measurement and status data received on the serial I/O port and send them to the display.

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 source. Communication between the dc source and an 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 source are located on the A2 Interface board. 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 (referenced to the supply’s output common).

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. Communication between the A1 and A2 boards is accomplished via a 30-pin connector.

NOTE: Agilent 66111A, 66311A, and earlier 66311B units with through-hole boards have a 28-pin

connector between the A1 and A2 boards. Some signals on the 28-pin connector differ from the signals on the 30-pin connector described in this section. Refer to Table 3-4 for the differences.

The logic array also directly communicates with the A1 main board via a number of level-sensitive signal lines, which perform the following functions: C_Mux_Ctrl_1 and C_Mux_Ctrl_2 control the readback multiplexer for output 2 and the DVM; Status_Ctrl_1 and Status_Ctrl_2 control the Status readback multiplexer. The PM_Inhibit control signal is used to shut down the bias voltage to the output stages and keep the dc source output off. The OV_SCR* control signal is used to fire the SCR. The Status_Detect signal informs the array of the present operating mode (either CV or CC) of both the main output and output 2. The OV_Detect signal indicates if an overvoltage condition has occurred on the Main output.

Principles of Operation - 4

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 source.

The Quad 8-bit DAC converts programmed information for the following circuits into analog format: output 2 voltage programming (CV_Prog_2), output 2 current programming (CC_Prog_2), overvoltage setting (OV_Prog), and fan speed programming (Fan_Prog). The CV_Prog_2 and CC_Prog_2 signals control the magnitude of the output 2 voltage in the CV mode and output 2 current in CC mode. The OV_Prog signal is applied to the OV detect circuit of the main output, 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 or output current increases, and to slow the fan speed down as temperature or current decreases.

The 16-bit ADC in conjunction with a 4x1 multiplexer returns data from the following measurement signals to the logic array: monitored peak current (Imon_P), monitored high-range current (Imon_H), readback signal for output 2 and the DVM (Rdbk_16bit), and monitored output voltage (VMon). All measurement signals are in the range of 0 to +5V, which corresponds to the zero to full-scale readback capability of the dc source.

The 8-channel, 8-bit ADC returns the following signals to the logic array: overvoltage programming (OV_Prog), high-range output current (Imon_H), voltage and current of output 2 (Rdbk_16bit), main output voltage (V_Mon), ambient temperature (Temp_Amb), and heatsink temperature (HS_Therm). The logic array varies the Fan_Prog signal depending upon the ambient temperature and the main output current.

A1 Main Board Circuits

Power Circuits

As shown in figures 6-2 and 6-4, the power circuits consist of: input power rectifiers and filter, primary and secondary bias circuits, an output regulator, a downprogrammer circuit, current-monitoring resistors, an overvoltage SCR, and an output filter.All bias circuits are located on the A1 pc board. Bias voltage test points are shown in figure 6-1 and transformer wiring diagrams are shown in figure 3-3.

The primary bias circuits are referenced to chassis (earth) ground. They provide the bias for the GPIB, RS232 and RI/DFI interfaces, the interface micro-processor circuits and the front panel.

The secondary bias circuits are referenced to secondary (output) common and are isolated from the chassis ground. They provide the bias for the amplifier and output circuits located on the A1 pc board. They also provide the bias for the logic array, EEPROM, DAC and ADC circuits and the secondary side of the Opto-isolators on A2.

As shown in figure 6-2, 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 dc source. The output regulator stage consists of two parallel NPN series regulators mounted on a heatsink and connected between the +Rail and the +Output. 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).

4 - Principles of Operation

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.

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 voltage across RmLo to about 1.5 volts. This corresponds to approximately 30 mA (20mA is the maximum rating of the low current range). An output filter capacitor provides additional filtering of the dc output.

Control Circuits

As shown in Figure 6-2, 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. The output voltage is monitored through the +S and -S sensing terminals. If local sensing is being used, the output voltage is monitored at the output terminals. If remote sensing is being used, the output voltage is monitored where the remote sense leads are 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 positive gross current limit circuit protects the output if the output current exceeds the maximum current rating of the unit. A negative gross current limit prevents the unit from sinking too much current.

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 (Q302 and Q304) clamps the voltage across RmLo to approximately 1.5 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 signals 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 array 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 gated 15V bias supplies, and update the status of the unit.

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

4. When a output protection clear command is executed, the microprocessor circuits resets the OV circuits, turns on the gated 15V biases, 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 heatsink temperature as well as the output voltage and current of the supply.

Output 2

As shown in Figure 6-5, the output 2 circuits consist of input power rectifiers and filter, an output regulator, a downprogrammer circuit, current-monitoring resistor, an output filter, the CV/CC control, output voltage/current monitor, and an inhibit circuit. Ouptut 2 data is transferrred between the output 2 circuits and the primary interface via the CV_Prog2, CC_Prog2, Status_Detect, and the Rdbk_16bit signals.

NOTE: Isolation between the main output and output 2 is provided by isolation amplifiers and optical

isolation chips.

The ac input rectifier and filter converts ac input to a dc level. The output regulator regulates this dc level at the output. The output regulator stage consists of a P-channel FET series regulator connected between the +B Rail and the +B Output. The conduction of the series regulators is increased or decreased by the Control_2 signal from the CV/CC control circuits in order to regulate the output voltage (in CV mode), or output current (in CC mode).

A downprogramming FET is connected between the +B Output and the -B Output. The conduction of this FET is controlled by the Drive signal from the CV/CC control circuits. When the output is turned off, the downprogramming FET conducts and shunts current away from the load.

A current shunt resistor monitors the output current. A gross current limit circuit protects the output if the output current exceeds the maximum current rating of the output. An output filter capacitor provides additional filtering of the dc output.

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 B_CV_Detect or B_CC_Detect signal is returned to the secondary interface to indicate that the corresponding loop is in control.

4 - Principles of Operation

With the CV loop in control, the output voltage is regulated by comparing the programmed voltage signal CV_Prog2 (0 to +5V) with the output voltage sensed at the +B and -B Output. If the output voltage exceeds the programmed voltage, the Control_2 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_2 signal goes high, causing the regulator to conduct more and increase the output voltage. Depending on where the output sense leads are connected, the output voltage is either monitored at the supply’s B Output terminals, or at the load, with the the remote sense leads connected to the load.

With the CC loop in control, the output current is regulated by comparing the programmed current signal CC_Prog2 (0 to +5V), with the output current monitor B_Imon. The B_Imon signal is produced by measuring the voltage drop across current monitoring resistor and is in the 0 to +5V range, which corresponds to the zero to full-scale output current range. If the output current exceeds the programmed value, the Control_2 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_2 signal goes high, causing the output regulator to conduct more and increase the output current.

When the downprogramming FET is turned on (in either CV or CC mode), current is conducted away from the load, which speeds up downprogramming.

During operation, an Inhibit_2 signal causes the Output Regulator to turn off if any of the following occur:

The output 2 is programmed off. The line voltage falls below 90 volts (approximately).

Current readback is provided by a multiplexer that alternately reads both output voltage and output current. Switches at the front end of the multiplexer toggle between the B_Imon and the B_Vmon signal depending on whether the C_Mux_Ctrl_1 signal is high or low. When the signal is low, the output voltage is read. When the signal is high, the output current is read.

A5 DVM Circuits

The circuits on the A5 DVM board measure the voltage signal applied to its input terminals. Differential amplifiers on the A5 board amplify and subtract the + and - DVM inputs and create an output signal referenced to Output 1 common. The resultant signal is transferred from the A5 board to the A2 interface assembly via cable W13. All analog-to-digital conversion functions are accomplished on the A2 interface board using the same ADC circuits that are used to perform the readback functions on the dc source output. Because the inputs to these measurement circuits are multiplexed, you cannot simultaneously make DVM measurements while measuring the dc source output. Also, because the measurement circuits of the DVM are internally referenced to the minus terminal of the main output, the DVM cannot measure voltages greater than +25 Vdc or less than −4.5 Vdc with respect to the negative terminal of the main output. The A5 DVM board is assembly-level replaceable; it contains no user-replaceable parts.

A6 Option 521 Relay Circuits

The A6 Option 521 relay board incorporates solid-state relays to connect and disconnect the outputs of the dc source. The relays are available on the - Out and - sense terminals of Output 1 and on the + Out and + sense terminals of Output 2. When the solid state relays are open, the output impedance is effectively raised to about 500k ohms for output 1, and about 200k ohms for output 2. The output relays are controlled by signals generated on the A2 Interface board, which are transferred to the relay board via cable W9. Cable W10 is used to daisy-chains other signals such as the output on/off signals from the A2 Interface board to the A1 board. Cable W11 connects the relays to the outputs of the dc source. The A6 Option 521 relay board is assembly-level replaceable; it contains no userreplaceable parts.

Replaceable Parts List

Introduction

This section lists the replaceable parts for all models. Refer to figures 5-1 and 5-2 for the location of mechanical parts with the reference designators MP.

Table 5-1. Chassis, Electrical

Designator Part_Number Qty Description

***** SURFACE-MOUNT UNITS ONLY *****

(refer to title page for serial numbers)

A1 66311-61021

66311-61027 66309-61020

5064-0129 66311-61028

66311-61029 5064-0095

5064-0138

5064-0094 1 66309D Tested PCA (Option 501) A2 5064-0098 1 66311B/D, 66309B/D Tested Interface PCA A3 66309-60001

66311-61021 A5 5064-0045 1 66311D, 66309D Tested DVM PCA

5064-0100

5064-0087 A6 5064-0092

66309-61025 A7 5064-0097 1 Output 2 Downprogrammer PCA (Option 501) B1 06632-60002 1 Fan Assembly F301 2110-0773 1 Fuse, 1.6AT, 250V, surface-mount (230Vac input)

2110-0638 1 Fuse, 3.15AT, 250V, surface-mount (115Vac input) F302, 04, 07 2110-0671 3 Fuse 0.125AM, 125V F303, 05, 06 2110-0699 3 Fuse, submin, 5AM 125V F309 2110-0951 1 Fuse, submin, 5AT 125V F310 2110-0932 1 Fuse, surface-mount, 5AM 125V F311 2110-1138 1 Fuse, surface-mount, 15AM FB760 2110-0967 1 Fuse, submin, 4AT, 125V FB761 2110-0712 1 Fuse, submin, 4AM, 125V (66309B/D output 2) G1 0960-0892 1 Rotary pulse generator

These board assemblies are only used on units with firmware revision A.02.04 and up (see chapter 3).

1 66311B/D Tested PCA (printed circuit assembly)

1 66309B/D Tested PCA

1 66311B Tested PCA (J02)

1 66309D Tested PCA (Option 521)

1 1

1 66311D, 66309D Tested DVM PCA (Option 521)

1 Relay Board (Option 521)

Complete Front Assembly (includes frame, keypad, PCA, etc.) Tested Printed Circuit Assembly (PCA) only

5 - Replaceable Parts List

Table 5-1. Chassis, Electrical (continued)

Designator Part_Number Qty Description

T1 9100-5276 1 Main Power Transformer W1 06611-80033 Primary Power Cable (T1 to A1 E312/313) W2 5063-3479 1 Secondary Power Cable (T1 to A1 J305) W3 5064-0011 1 Secondary Power Cable (T1 to A1 J303) W4 5064-0008 1 Secondary Bias Cable (T1 to A1 J304) W5 5064-0010 1 66309B/D Output 2 Bias Cable (T1 to A1 J306) W6 5080-2452 1 Interface Power Cable (E320/321 to A2J206) W7 5080-2457 1 Display Power/Comm Cable (A2 J211 to A3) W8 5080-2640 1 Interface Signal/Bias Cable (A1 J307 to A2 J207) W9 5081-4996 1 Relay /Comm Cable (A2 J10 to A6 J621) W10 5080-2683 1 Relay /Comm Cable (A1 J804 to A6 J623) W11 5080-2682 1 Relay /Output Cable (A1 J320 to A6 J620) W12 5064-0009 1 Secondary Power Cable (T1 to A1 JB760) W13 5080-2644 1 DVM /Comm Cable (A5 J3 to A1 J800)

06611-60056 2 T1 Primary Jumper (orange)

***** THROUGH-HOLE UNITS ONLY *****

(refer to title page for serial numbers)

A1 66111-61020 1 66111A Printed Circuit Assembly (PCA)

66311-61025 1 66311A/B Tested PCA (through-hole) A2 5064-0086 1 66111A Tested Interface PCA (for through-hole units)

5064-0085 1 66311A/B Tested Interface PCA (for through-hole units) A3 5064-0016

5063-3430 A4 06611-60022 1 66311A Binding Post PCA B1 06632-60002 1 Fan Assembly F301 2110-0007 1 Fuse, 1AT, 250V, rear mounted (230Vac input)

2110-0303 1 Fuse, 2AT, 250V, rear mounted (115Vac input) F302, 04, 07 2110-0671 3 Fuse 0.125AM, 125V F303, 05, 06 2110-0699 3 Fuse submin. 5AM, 125V F308, 310 2110-0699 2 Fuse submin. 5AM, 125V F309 2110-0951 1 Fuse submin. 5AT, 125V G1 0960-0892 1 Rotary pulse generator S1 5080-2600 1 66311A AC calibration switch (with R415) T1 9100-5232 1 Main Power Transformer W1 06611-80003 1 Primary Power Cable (T1 to A1 E312/313) W2 06611-80005 1 Secondary Power Cable (T1 to A1 J305) W3 06611-80006 1 Secondary Power Cable (T1 to J303) W4 06611-80004 1 Secondary Power Cable (T1 to A1 J304) W6 5080-2452 1 Interface Power Cable W7 5080-2457 1 Display Power/Comm Cable W8 5080-2448 1 Interface Signal/Bias Cable

06611-60056 2 T1 Primary Jumper (orange)

06611-80007 1 Output Cable - 66311A only (E315B/E315R to A4 board)

1 1

Complete Front Assembly (includes frame, keypad, PCA, etc.) Tested Printed Circuit Assembly (PCA) only

Replaceable Parts List - 5

Table 5-2. Chassis, Mechanical

Designator Part_Number Qty Description

***** SURFACE-MOUNT UNITS ONLY *****

(refer to title page for serial numbers)

MP1 5002-1519 1 Chassis MP3 33120-40200 1 Front Frame MP4 66311-80002 1 Nameplate - 66311B

66311-80003 1 Nameplate - 66311D 66309-80001 1 Nameplate - 66309B

66309-80002 1 Nameplate - 66309D MP5 5080-2617 1 Window MP6 06611-40001 1 Pushrod (Ref Line Switch) MP7 06611-40002 1 Keypad MP8 33120-87401 1 Knob MP9 5001-0538 2 Side Trim MP10 5040-1723 1 Side Bracket, Right MP11 1400-0977 3 Ground Clip MP12 0515-0433 7 Screw, M4x0.7x16mm, Torx T15, Pan, Conical cup

0515-0433 2 Screw, M4x0.7x16mm, (Option 521 board) MP13 5041-8801 4 Foot MP14 06611-00002 1 Cover MP15 03478-88304 1 Rear Bezel MP16 1252-1488 1 Terminal Block, 4 Position, RI/DFI MP17 0360-2604 2 Terminal Block, 5 Position, Output/Sense MP18 8120-8821 1 Local sense jumper MP19 1252-8670 1 Terminal Block, 3 Position, DVM MP20 0380-4636 1 Spacer, snap-in (ref GPIB board) MP21 0515-0374 7 Screw, M3x0.5x10mm, Torx T10, Pan, Conical cup MP22 06611-00004 1 Transformer Bracket MP23 06611-40006 1 Fan Spacer MP24 5080-2649 1 Rear Panel Label MP25 1252-3056 2 Screw Lock Kit (ref RS232 Connector) MP26 3050-0849 2 Flat Washer, #10 MP27 2190-0586 2 Helical Lock Washer, M4 MP28 0380-0644 2 Stud Mounted Standoff (ref GPIB Connector) MP29 0360-2670 Screw, DVM board MP30 5080-2637 Front Panel Keypad Label

5 - Replaceable Parts List

Table 5-2. Chassis, Mechanical (continued)

Designator Part_Number Qty Description

***** THROUGH-HOLE UNITS ONLY *****

(refer to title page for serial numbers)

MP1 5002-1510 1 Chassis MP2 06611-00003 1 Side Bracket, Left MP3 33120-40200 1 Front Frame MP4 66111-80001 1 Nameplate - 66111A

5080-2594 1 Nameplate - 66311A

66311-80002 1 Nameplate - 66311B MP5 5080-2617 1 Window MP6 06611-40001 1 Pushrod (Ref Line Switch) MP7 06611-40002 1 Keypad MP8 33120-87401 1 Knob MP9 5001-0538 2 Side Trim MP10 06611-00005 1 Side Bracket, Right MP11 1400-0977 3 Ground Clip MP12 0515-0430 8 Screw M4x0.7x8mm, Torx T15, Pan, Conical cup MP13 5041-8801 4 Foot MP14 06611-00002 1 Cover MP15 03478-88304 1 Rear Bezel MP16 1252-1488 1 Terminal Block, 4 Position, RI/DFI MP17 0360-2604 1 Terminal Block, 5 Position, Output/Sense MP21 0515-0374 7 Screw, M3x0.5x10mm, Torx T10, Pan, Conical cup MP22 06611-00004 1 Transformer Bracket MP23 06611-40006 1 Fan Spacer MP24 66311-80001 1 Rear Panel Label MP25 1252-3056 2 Screw Lock Kit (ref RS232 Connector) MP26 3050-0849 2 Flat Washer, #10 MP27 2190-0586 2 Helical Lock Washer, M4 MP28 0380-0644 2 Stud Mounted Standoff (ref GPIB Connector) MP30 5080-2637 Front Panel Keypad Label (66111A, 66311B)

06611-80001 Front Panel Keypad Label (66311A) MP31 2110-0927 1 Fuseholder with cap MP32 0370-2862 1 Pushbutton (Ref Sense Switch) MP33 06611-40005 1 Support Plate MP34 1400-1281 1 Cable Clip (ref 66311A) MP35 0590-0305 2 Hex Nut 6-32 w/Lockwasher (ref 66311A) MP36 1510-0091 2 Binding Post (ref 66311A)

Replaceable Parts List - 5

MP32

MP31

MP33

MP12

MP29

MP28

MP27

MP26

MP25

MP24

MP18

MP23

MP19

MP20

MP12

MP21

MP11

MP10

MP9

MP34

MP35

MP30

MP12

MP36

MP22

MP17

MP16

MP15

MP14

MP13

MP21

MP1

MP2

MP12

MP3

MP4

MP12

MP8

MP7

MP6

MP5

Figure 5-1. Mechanical Parts Identification

Diagrams

Introduction

This chapter contains drawings and diagrams for troubleshooting and maintaining the Agilent Model 66111A, 66311A/B/D, and 66309B/D Mobile Communications DC Sources.

+Rail fuse

+12V bias for output 2 (pin 15)

-5V bias for output 2 (pin 16)

Output 2 fuse

-Rail fuse

+Rail for output 2

+Rail

+5V bias for output 2 (pin 1)

Downprogrammer fuse

Output fuse

J306

J304

F311

F310

HEAT SINK

FAN

FB761

+5V/+-15V bias fuses

F303

J305

F305

C753

J307

F306

J303

F301

Common for Output 2

Line fuse

+ 5V GPIB bias fuse

+ 15V jumper

- 15V jumper + 2.5V reference (+ C753)

JB760

QB762

F312

UB771

R423

R885

R419 R422

J314

J804

J800

UB760

+ 5V jumper

F309

R899

Common for Main Output CC Control Loop

OUTPUT

CAP

R428

R429

CV Control Loop

JB761 J309

- Output 2

- Output

Figure 6-1A. A1 Main Board Test Points (surface-mount boards)

6 - Diagrams

+Rail/-Rail bias fuses

-15V secondary gated

+15V secondary gated

+Rail

Output fuse

-Rail

+15V secondary

FAN

HEAT SINK

J304

J314

F308 F310

+5V/+-15V bias fuses

J305

F306 F303

D307

R419 R423

F302

F304

F309

R421

R418

J303

F305

R422

R431

+ 5V GPIB bias fuse

S301

BLK

WHT

J307

RED

MOON

BOARD

+5V Primary

Downprogrammer fuse

F307

+2.5V Reference (pin 6)

+5V Secondary

-15V Secondary

SCR/crowbar jumper

Reverse polarity

diode jumper

CAP

OUTPUT

F301

J309

S302

Figure 6-1B. A1 Main Board Test Points (through-hole boards)

Diagrams - 6

Output Regulator

Rm Lo

Rm Hi

+ Output

Q308

High BW C Amp

- Output

MUX

Imon_L

Rdbk_16bit

Hi Rng Imon Amp

Imon_P

T301

OV_detect*

OV_prog

OV_SCR*

OV Detect

F309

D312

Control

Crowbar

CR301

Q302

Drive

Shunt

Shunt Clamps

Q304

Q303

U309A

Clamp

Q306

Q309

U308A

Lo Rng Imon Amp

Pos C Control

+15V

Control Amp

Down Programmer

DP_Control

Neg

Gross

Current

Limit

- 15V

CC_prog

Imon_H

Status_detect

MUX

Inverter

CC Detect

D321

l tro

n o C

Pos Gross Current Limit

+2.5V

Vmon

Vmon Amp

Inverter

CV Detect

V Control

+5V

Inner Loop

D317

RT301

PM_Inhibit

Fan_Prog

HS_Therm

CV_prog

Fan Driver

Fan

C374

+ Rail

D330 - D333

C371

Output Stage

+/- 15V

Gated Bias

D341 - D344

- Rail

Bias Shutdown

Figure 6-2. A1 Board Block Diagram

6 - Diagrams

IMon_H

OV_Prog

Rdbk_16bit

CC_Prog_2

OV_Prog

Fan_Prog

Status_Ctrl_1

C_Mux_Ctrl_1

Status_Ctrl_2

PM_Inhibit

OV_SCR*

C_Mux_Ctrl_2

To A1 Main PC Assembly

Status_Detect*

OV_Detect*

IMon_P

IMon_H

VMon

Rdbk_16bit

CV_Prog

CV_Prog_2

CC_Prog

VMon

HS_Therm

Temp_Amb

Zylinx

PROM

Boot ROM

EEPROM

Zylinx

Opto-

Isolators

Address Bus

Serial Bus

Data Bus

DSP

ROM

Logic Array

RAM

256Kx16

32Kx16

MUX

16 Bit ADC

GAL

Prog

Logic

HPIB

Interface

Dual

12 Bit DAC

Dual

Asyn

RS232

Control

Interface

Quad

8 Bit DAC

RI/DFI

Interface

8 Channel

8 Bit ADC

Front Panel

Secondary

Common

Ground

Chassis

Connector

Isolation

RPG

Display

Driver

Display

Figure 6-3. A2/A3 Boards Block Diagram

Keypad

Front Panel Assembly A2 Interface Assembly

Diagrams - 6

567

J206

J111

J211

A2 A3

87654

202122

F304

+2.5V Ref

+15V Sec

+ RAIL

U755

RAIL_CT

B +12V

FB760

B -5V

UB764

UB765

+B RAIL

- RAIL

J307 J207

+15V Sec

U304

+26V (to Fan Ckt)

F300

+5V Sec

U302

222023

Sec Com

F301

-15V Sec

U300

White

+5V

+5V Pri

U301

Red

Black

Pri Com

F304

J306

20Vac

J304

20Vac

JB760

20Vac

J305

20Vac

J303

11Vac

Figure 6-4. Rail and Bias Circuits

6 - Diagrams

CC_prog_2

+ B Output

CB776

FB761

Gross Current Limit

UB858

Downprogrammer

QB857

- B Output

- 5V

UB761

B_Imon

RB369

- 5V

UB857

Drive

DB857

UB769

UB762

DB760

CV_prog_2

- 5V

UB760

UB769

UB762

DB760

Output Regulator

B_VMon

QB762

QB761

+B RAIL

Control_2

+12V

Opto-

isolator

UB773

B_CC_Detect

Opto-

isolator

QB764

INHIBIT_2

MUX

Status_Detect

B_CV_Detect

+5V

Opto-

isolator

C_Mux_Ctrl_1

UB772

B_IMon

UB771

UB768

MUX

Rdbk_16bit

Figure 6-5. Output 2 Circuits

Index

—+—

+OUT, 41 +sense, 41

—A—

A1 block diagram, 54 A1 board removal, 38 A1 Main board, 43 A2 board removal, 37 A2 Interface Board, 42 A2/A3 block diagram, 55, 56 A2S201, 43 A3 board removal, 38 A3 Front Panel, 42 ADC, 42

CV loop, 44 CV Noise, 15 CV source effect, 14 CV/CC control, 43, 44, 45 CV_Detect, 44 CV_Detect*, 42 CV_Prog, 43, 44 CV_Prog2, 45

—D—

DAC, 42 disable protection, 32 disassembly - tools, 35 disassembly procedure, 35 downprogramming, 43, 44 DP_Control, 43 DVM circuits, 46

—B—

B_CC_Detect, 45 B_CV_Detect, 45 B_IMon, 45 B_VMon, 45 bias voltages, 30

—C—

C_Mux_Ctrl, 45 cal denied, 33 calibration, 33 calibration - post repair, 32 CC, 30 CC line regulation, 17 CC load effect, 18 CC load regulation, 17 CC loop, 44 CC noise, 18 CC- operation, 16, 17 CC source effect, 18 CC_Detect, 44 CC_Detect*, 42 CC_Prog, 43, 44 CC_Prog2, 45 clear password, 32 constant current tests, 16 constant voltage tests, 14 Control, 43, 44 Control_2, 45 copyrights, 5 cover removal, 37 current monitoring resistor, 13 current sink, 16, 17 CV, 30 CV load effect, 14

—E—

EEPROM, 43 electronic load, 13 electrostatic discharge, 10 error codes, 29

—F—

fan speed, 32 Fan_Prog, 43, 44 firmware revisions, 10, 33 FLT, 41 front panel removal, 37

—H—

hazardous voltages, 9 history, 5 HP-IB, 41 HS_Therm, 43

—I—

identification, 5 IDN? query, 33 Imon_H, 43, 44 Imon_L, 43 Imon_P, 43 INH, 41 inhibit calibration, 33 initialization, 33 interface signals, 41

Index

—J—

J207 voltages, 31

—M—

manual revisions, 10

—N—

notice, 5

—O—

Option 521, 46

-OUT, 41 out of range, 32 OV_Detect, 44 OV_Detect*, 42 OV_Prog, 43 OV_SCR*, 42, 44

—P—

PARD, 15, 18 password, 32 performance test form, 19 performance tests, 13 PM_Inhibit, 44 power-on self-test, 29 primary interface, 42 printing, 5 programming, 13 programming and output values, 13 protection, 32

ROM upgrade, 33 RPG, 42 RS-232, 41

—S—

safety considerations, 9 safety summary, 3 SCR, 44 secondary interface, 42 self-test, 29

-sense, 41 sense switch, 44 serial number, 5 series regulator, 43 shunt clamp, 44 status annunciators, 30

—T—

Temp_Amb, 43 test equipment, 11 test setup, 12 trademarks, 5 transformer removal, 39 transient recovery, 15 troubleshooting - bias and reference supplies, 30 troubleshooting - equipment, 24 troubleshooting - flowcharts, 24 troubleshooting - introduction, 23 troubleshooting - overall, 24 troubleshooting - status annunciators, 30

—U—

UNR, 30

—R—

rail and bias circuits, 57, 58 readback accuracy, 14 reference voltages, 30 Relay circuits (Option 521), 46 replaceable parts - chassis, 47 revisions, 10 RmHi, 44 RmLo, 44

—V—

verification tests, 13 VMon, 43, 44 voltage programming, 14

—W—

warranty, 2

Manual Updates

The following updates have been made to this manual since its publication.

1/12/01 Transient response performance testing has been updated in Chapter 2.

Agilent 66111A Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

WARRANTY

Safety Summary

Printing History

Instrument Identification

Table of Contents

Introduction

Safety Considerations

Related Documents

Revisions

Electrostatic Discharge

Test Equipment Required

Measurement Techniques

Operation Verification Tests

Performance Tests

Constant Voltage (CV) Tests

Constant Current (CC) Tests

Performance Test Equipment Form

Performance Test Record Form

Troubleshooting

Test Equipment Required

Overall Troubleshooting

Specific Troubleshooting Procedures

Post-repair Calibration

Initialization

ROM Upgrade

Disassembly Procedures

Principles of Operation

I/O Interface Signals

A3 Front Panel Circuits

A2 Interface Circuits

A1 Main Board Circuits

A5 DVM Circuits

A6 Option 521 Relay Circuits

Replaceable Parts List

Diagrams

Index

Manual Updates