Keysight 669 A Series User manual

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Service Manual
Keysight Series 669xA
GPIB DC Power Supplies

SERVICE MANUAL
GPIB DC Power Supplies
Keysight Series 669xA
For instruments with Serial Numbers:
Keysight 6690A: MY41000131
Keysight 6691A: MY41000119
Keysight 6692A: MY41000133
For manual updates, a change page may be included.
For a history of manual updates, see Appendix A.
Keysight Part No. 5969-2907 Printed in Malaysia
December, 2014

2
CERTIFICATION
Keysight Technologies certifies that this product met its published specifications at time of shipment from the factory.
Keysight 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 Keysight Technologies hardware product is warranted against defects in material and workmanship for a period of
three years from date of delivery. Keysight Technologies software and firmware products, which are designated by
Keysight 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 Keysight Technologies will, at its option, either repair or replace
products which prove to be defective. Keysight Technologies does not warrant that the operation of 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 Keysight Technologies. Customer shall prepay shipping charges by (and shall pay all duty and taxes) for products
returned to Keysight Technologies for warranty service. Except for products returned to Customer from another country,
Keysight Technologies shall pay for return of products to Customer.
Warranty services outside the country of initial purchase are included in Keysight Technologies product price, only if
Customer pays Keysight Technologies international prices (defined as destination local currency price, or U.S. or Geneva
Export price).
If Keysight 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 Keysight 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. KEYSIGHT 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. KEYSIGHT
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 contracts, product
maintenance agreements and customer assistance agreements are also available. Contact your nearest Keysight
Technologies Sales and Service office for further information on Keysight Technologies' full line of Support Programs.

3
SAFETY CONSIDERATIONS
GENERAL. This is a Safety Class 1 instrument (provided with terminal for connection to protective earth ground).
OPERATION. 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".
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.
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). Grounding one conductor of a two-conductor outlet is
not sufficient protection.
If this instrument is to be energized via an auto-transformer (for voltage change), make sure the common terminal is
connected to the earth terminal of the power source.
Any interruption of the protective (grounding) conductor (inside or outside the instrument), or disconnecting of the
protective earth terminal will cause a potential shock hazard that could result in personal injury.
Whenever it is likely that the protective earth connection has been impaired, this instrument must be made inoperative
and be secured against any unintended operation.
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.
Do not operate this instrument in the presence of flammable gases or fumes.
Do not install substitute parts or perform any unauthorized modification to this instrument.
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.
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.
Capacitors inside this instrument may hold a hazardous electrical charge even if the instrument has been disconnected
from its power source.
SAFETY SYMBOLS
Instruction manual symbol. The instrument will be marked with this symbol when it is necessary for you to refer to the
instruction manual in order to protect against damage to the instrument.
This sign indicates hazardous voltages.
This sign indicates an earth terminal (sometimes used in the manual to indicate circuit common connected to a ground
chassis).
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.
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.
.

4
Safety Symbol Definitions
Symbol
Description
Symbol
Description
Direct current
Terminal for Line conductor on permanently
installed equipment
Alternating current
Caution, risk of electric shock
Both direct and alternating current
Caution, hot surface
Three-phase alternating current
Caution (refer to accompanying documents)
Earth (ground) terminal
In position of a bi-stable push control
Protective earth (ground) terminal
(Intended for connection to external
protective conductor.)
Out position of a bi-stable push control
Frame or chassis terminal
On (supply)
Terminal for Neutral conductor on
permanently installed equipment
Off (supply)
Terminal is at earth potential
(Used for measurement and control
circuits designed to be operated with
one terminal at earth potential.)
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.
Printing History
The edition and current revision of this manual is 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. Significant changes to the manual occurring
between revisions are covered by change sheets shipped with the manual. Note that not all changes made to the power
supply affect the content of the manual. Refer to appendix A for a history of manual updates.
Edition 1 November, 2002
Edition 2 December, 2014
© Copyright 2002, 2014 Keysight Technologies
This document contains proprietary information protected by copyright. All rights are reserved. No part of this document
may be photocopied, reproduced, or translated into another language without the prior consent of Keysight Technologies.
The information contained in this document is subject to change without notice.

5
Table of Contents
Introduction ............................................................................................................................................................................ 7
Scope and Organization ...................................................................................................................................................... 7
Instrument Identification..................................................................................................................................................... 7
Related Documents .......................................................................................................................................................... 8
Manual Revisions............................................................................................................................................................. 7
Firmware Revisions ......................................................................................................................................................... 8
Safety Considerations ......................................................................................................................................................... 8
Electrostatic Discharge ....................................................................................................................................................... 8
Verification.............................................................................................................................................................................. 9
Introduction......................................................................................................................................................................... 9
Tests.................................................................................................................................................................................... 9
Test Equipment Required.................................................................................................................................................... 9
Equipment List................................................................................................................................................................. 9
Current-Monitoring Resistor ............................................................................................................................................ 9
Electronic Load ................................................................................................................................................................ 9
Programming the Tests ..................................................................................................................................................... 10
General Considerations .................................................................................................................................................. 10
General Measurement Techniques.................................................................................................................................... 11
Performance Test Record Sheets ...................................................................................................................................... 11
Operation Verification Tests............................................................................................................................................. 11
Performance Tests............................................................................................................................................................. 11
Constant Voltage (CV) Tests ......................................................................................................................................... 12
Constant Current (CC) Tests.......................................................................................................................................... 15
Averaging the CC Measurements................................................................................................................................... 19
Troubleshooting .................................................................................................................................................................... 25
Introduction....................................................................................................................................................................... 25
Test Equipment Required ............................................................................................................................................. 25
Power-On Selftest ............................................................................................................................................................. 26
Troubleshooting Charts.................................................................................................................................................. 26
Firmware Revisions ....................................................................................................................................................... 42
Test Headers................................................................................................................................................................... 42
Post-Repair Calibration..................................................................................................................................................... 43
When Required .............................................................................................................................................................. 43
Inhibit Calibration Jumper ............................................................................................................................................. 43
Calibration Password ..................................................................................................................................................... 43
Restoring Factory Calibration Constants ....................................................................................................................... 44
EEPROM Initialization..................................................................................................................................................... 44
Transferring Calibration Constants to Factory Preset Locations....................................................................................... 44
Disassembly Procedures ................................................................................................................................................... 48
Tools Required............................................................................................................................................................... 49
Top Cover ...................................................................................................................................................................... 49
Removing Protective RFI Shield (Galvanized Sheet Metal).......................................................................................... 49
GPIB Board.................................................................................................................................................................... 49
A4 AC Input Assembly.................................................................................................................................................. 50
A5 DC RAIL Assembly ................................................................................................................................................. 50
A6 BIAS Assembly........................................................................................................................................................ 50
A3 FET Board................................................................................................................................................................ 50
A10 Control Assembly................................................................................................................................................... 50
Front Panel Assembly .................................................................................................................................................... 51
S1 Line Switch ............................................................................................................................................................... 51
A1 Front Panel Board..................................................................................................................................................... 51

6
A1DSP1 LCD Display ................................................................................................................................................... 51
A1G1 and A1G2 Rotary Controls.................................................................................................................................. 51
A1KPD Keypad ............................................................................................................................................................. 51
Output Bus Boards A7, A81 and A9 & Chassis Components........................................................................................ 52
Principles of Operation ........................................................................................................................................................ 59
Introduction....................................................................................................................................................................... 59
A2 GPIB Board................................................................................................................................................................. 59
A1 Front Panel Assembly ................................................................................................................................................. 60
A10 Control Board.......................................................................................................................................................... 60
A4 AC Input Board........................................................................................................................................................... 62
A5 DC Rail Board............................................................................................................................................................. 63
A3 FET Board................................................................................................................................................................... 63
Output Circuits.................................................................................................................................................................. 64
Replaceable Parts.............................................................................................................................................................. 65
Introduction...................................................................................................................................................................... 65
How to Order Parts ........................................................................................................................................................... 65
Diagrams................................................................................................................................................................................ 69
Introduction....................................................................................................................................................................... 69
Backdating............................................................................................................................................................................. 99
Index .................................................................................................................................................................................... 101

Introduction
7
1
Introduction
Scope and Organization
This manual contains information for troubleshooting and repairing Keysight Series 669xA, 6.6-kilowatt power supplies to
the assembly level. The supplied schematics at the back of the manual are not intended for component level repair, only to
provide additional information for isolating a problem to a specific assembly. The chapters of this manual are organized as
follows:
Chapter
Description
Chapter 2
Verification procedures to determine the performance level of the supply either before or after repair.
Chapter 3
Troubleshooting procedures for isolating a problem, procedures for replacing the defective assembly
and, if required, post-repair calibration and EEPROM initialization procedures.
Chapter 4
Principles of power supply operation on a block-diagram level.
Chapter 5
Assembly-level replaceable parts, including parts ordering information.
Chapter 6
Diagrams, including schematics, component location drawings, and troubleshooting test points.
Instrument Identification
Keysight Technologies instruments are identified by a 10-digit serial number. The format is described as follows: first two
letters indicate the country of manufacture. The next four digits are a code that identify either the date of manufacture or of
a significant design change. The last four digits are a sequential number assigned to each instrument.
Item Description
MY The first two letters indicates the country of manufacture, where US = USA; MY = Malaysia.
3648 This is a code that identifies either the date of manufacture or the date of a significant design change.
0101 The last four digits are a unique number assigned to each power supply.
Manual Revisions
The edition and current revision of this manual is indicated on page 4. 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. Significant changes to the manual
occurring between revisions are covered by change sheets shipped with the manual. Note that not all changes made to the
power supply affect the content of the manual. Refer to appendix A for a history of manual updates.
This manual was written for power supplies that have the same serial prefixes (first part) as those listed on the title page and
whose serial numbers (second part) are equal to or higher than those listed in the title page.
Note
1) A revised edition incorporates all new or corrected material since the previous printing date.
2) If they are significant to the operation and/or servicing of the power supply, those differences are
documented in one or more Manual Changes sheets included with this manual. These changes will also
be incorporated at future updates of the manual.
3) A history of changes to this manual that affect previously manufactured units is provided in Appendix A
- Manual Backdating.

Introduction
8
Firmware Revisions
The power supply's firmware resides in the A10 control board microprocessor chip and in ROM chips on the A2 GPIB and
A1 Front Panel boards. You can obtain the firmware revision number by either reading the integrated circuit label, or query
the power supply using the GPIB *IDN query command (see Chapter 3 - Troubleshooting). Also, see Chapter 3, Firmware
Revisions for the actual Keysight BASIC program that does this.
Related Documents
Operating and Programming Manuals
Each power supply is shipped with an operating and programming manual (see Replaceable Parts, Chapter 5 for part
numbers) that covers the following topics:
Options, accessories, specifications, supplementary characteristics, output characteristic curve, typical output
impedance curves.
Connecting the power cord, load, and remote sensing.
Connecting power supplies in series or autoparallel.
Connecting the remote controller and setting the GPIB address.
Configuring the digital port for remote inhibit, relay link, or digital I/O operation.
Connecting the analog port for external voltage programming control.
Turn-on tests, including selftest errors and runtime errors.
Front panel operation.
SCPI programming, an introduction to syntax, language dictionary, and status register operation.
Compatibility-language programming for operation with Keysight Series 603xA power supplies.
Replacement of line fuse and conversion of line voltage.
Calibration procedure (front panel and remote).
Safety Considerations
This power supply is a Safety Class I instrument, which means it has a protective earth terminal. This terminal must be
connected to earth ground through a power source equipped with a 4-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 power
supply and review this manual for safety warnings and instructions. Safety warnings for specific procedures are located at
appropriate places in the manual.
Hazardous voltage exist within the power supply chassis, at the output terminals, and at the analog
programming terminals.
Electrostatic Discharge Precautions
The power supply has components that can be damaged by ESD (electrostatic discharge). Failure to
observe standard, antistatic practices can result in serious degradation of performance, even when an
actual failure does not occur.
When working on the power supply observe all standard, antistatic work practices. These include, but are not limited to:
working at a static-free station such as a table covered with static-dissipative laminate or with a conductive table mat
(Keysight P/N 9300-0797, or equivalent).
using a conductive wrist strap, such as Keysight P/N 9300-0969 or 9300-0970.
grounding all metal equipment at the station to a single common ground.
connecting low-impedance test equipment to static-sensitive components only when those components have power
applied to them.
removing power from the power supply before removing or installing printed circuit boards.

Verification 9
2
Verification
Introduction
This chapter provides test procedures for checking the operation of Keysight Series 669xA power supplies. The required
test equipment is specified and sample performance test record sheets are included. Instructions are given for performing
the tests either from the front panel or from a controller over the GPIB.
Tests
Two types of procedures are provided: Operation Verification tests and Performance tests.
Type of Test
Purpose
Operation Verification
These tests do not check all parameters, but comprise a short procedure to verify that the power
supply is performing properly.
Performance
These tests verify all the Specifications (not Supplementary Characteristics) listed in Table 1-1
of the Power Supply Operating Manual.
If you encounter failures or out-of-specification test results, see Troubleshooting Procedures (Chapter 3). The procedures
will determine if repair and/or calibration is required.
Note The power supply must pass the selftest at power-on before the following tests can be performed. If the
power supply fails selftest, go to Chapter 3.
Test Equipment Required
Equipment List
Table 2-1 lists the equipment required to perform the tests given in this chapter. Only the equipment marked with the
superscript "1'' is needed for the Operation Verification test.
Current-Monitoring Resistor
The four-terminal, current-monitoring resistor (current shunt) listed in Table 2-1 is required to eliminate output current
measurement error caused by voltage drops in leads and connections. The specified current shunts have special
current-monitoring terminals inside the load connection terminals. The accuracy of the current shunt must be 0.04% or
better. Connect the current monitor directly to these current-monitoring terminals.
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 must be used for connecting, disconnecting, and shorting the load resistor. For most tests, an
electronic load (see Table 2-1) is easier to use than a variable resistor. However, an electronic load may not be fast enough
for testing transient recovery time or may be too noisy for testing noise (PARD). In these cases, fixed load resistors of
suitable power dissipation can be used with minor changes to the test procedures given in this chapter.

10 Verification
Table 2-1. Test Equipment Required
Type
Required Characteristics
Recommended Model
Digital Voltmeter1
Resolution: 10 nV @ 1V
Keysight 3458A
Readout: 8 1/2 digits
Accuracy: 20 ppm
Current Monitor Resistor1
Keysight 6691A, 6692A:
Guildline 9230/300
0.0010.04%, 300A, 100W
Keysight 6690:
Burster Type 1280
0.00010.05%, 1000A, 100W
DC Power Supply
DC Power Source with current capability
equal to UUT
Keysight 6680A
Electronic Load
Resistor Load
Range: Voltage and current range must
exceed that of supply under test. Power:
7kW minimum
or
6.6 Kilowatt minimum
Keysight 6690A = 34.1 milliohms 6600W
Keysight 6691A = 136 milliohms 6600W
Keysight 6692A = 545 milliohms. 6600W
4 each Keysight N3300A, with/3
each Keysight N3306A per
mainframe for all units
Oscilloscope
Sensitivity: 1mV
Keysight Infinium
Bandwidth Limit: 20MHz
or equivalent
Probe: 1:1 with RF tip
RMS Voltmeter
True RMS Bandwidth: 20MHz
Rhode & Schwartz
Sensitivity: 100 V
Model URE3 RMS-P-P
voltmeter
Current Transformer
0.1Volt per ampere: 1Hz to 20MHz
Pearson Model 411
Variable-Voltage
Transformer (AC Source)
Power: 3 Phase 24KVA; Range:
180-235V 47 - 63Hz; 360- 440V
47 - 63Hz
Superior Powerstat
1156DT-3Y, 0-280V, 50A,
24.2 KVA or equivalent .
GPIB Controller2
Full GPIB capabilities
HP Series 200/300
1Required for Operation Verification Tests.
2 Required for remote testing of 669xA models.
Programming the Tests
General Considerations
Procedures are given for programming these tests either from the front panel keypad or from a GPIB controller. The
procedures assume you know how to use the front panel keypad or how to program over the GPIB (see the Power Supply
Operating Manual for more information). When using computer-controlled tests, you may have to consider the relatively
slow (compared to computer and system voltmeters) settling times and slew rates of the power supply. Suitable WAIT
statements can be inserted into the test program to give the power supply time to respond to the test commands.
This power supply can provide more than 240VA at more than 2 volts. If the output connections touch each
other, severe arcing can occur resulting in burns, ignition or welding of parts. DO NOT ATTEMPT
TO MAKE CONNECTIONS WHILE OUTPUT POWER IS ON. These connections should be performed
only by qualified electronics personnel.

Verification 11
Programming Parameters
Table 2-2 lists the programming voltage and current values for each model. You can enter these values either from the front
panel or from a controller over the GPIB.
Table 2-2. Programming Voltage and Current Values
Keysight Model
Full Scale
Max. Prog.
Full Scale
Max. Prog.
Max. Prog.
Voltage
Voltage
Current
Current
Overvoltage
Keysight 6690A
15V
15.375V
440A
450A
18V
Keysight 6691A
30V
30.75V
220A
225A
36V
Keysight 6692A
60V
61.5V
110A
112A
69V
General Measurement Techniques
Figure 2-1 shows the setup for the Constant Voltage tests. Measure the dc output voltage directly at the sense (+S and -S)
terminals. Connect these terminals for local sensing. Be certain to use load leads of sufficient wire gauge to carry the output
current (see Chapter 4 of the Power Supply Operating Manual). To avoid noise pickup, use coaxial cable or shielded pairs
for the test leads. If you use more than one meter or a meter and an oscilloscope, connect separate leads for each instrument
to avoid mutual-coupling effects.
Performance Test Record Sheets
When performing the tests in this chapter, refer to the Performance Test Record sheets supplied at the end of this chapter.
Table 2-6 is for recording common information, such as, the test equipment used and the environmental conditions. Tables
2-7 through 2-11 are dedicated to specific models. Each sheet lists the acceptable test ranges for the model and provides a
place to record the results of the test.
Note It is recommended that before you perform the tests in either Table 2-4 or Table 2-5, that you first locate
the appropriate Performance Test Record sheet from Tables 2-7 through Table 2-11 for your specific
model. Make a copy of this sheet, and record the actual observed values in it while performing the tests.
Use the sheets in Tables 2-7 through Table 2-11 as master reference sheets to run copies at any time.
Operation Verification Tests
Table 2-3 lists the requirements for operation verification, which is a subset of the performance tests.
Table 2-3. Operation Verification Tests
Test
Refer To
1
Turn-On Checkout
Power Supply Operating Manual
2
Voltage Programming and Readback Accuracy
Table 2-4
3
Current Programming and Readback Accuracy
Table 2-5
Note: Record the results of Tests 2 and 3 in the appropriate Performance Test Record sheets
Performance Tests
Performance tests check all the specifications of the power supply. The tests are grouped into constant-voltage mode tests
(Table 2-4) and constant-current mode tests (Table 2-5).

12 Verification
Constant Voltage (CV) Tests
Test Setup
Connect your dc voltmeter leads to only +S and -S (see Figure 2-1), because the power supply regulates the voltage
between these points, not between the + and - output terminals.
Test Procedures
Perform the test procedures in Table 2-4. The CV tests are:
Voltage Programming and Readback Accuracy
CV Load Effect
CV Source Effect
CV Noise (PARD)
Transient Recovery Time
Note The tests are independent and may be performed in any order.
a) CV Test Setup with 6.6kW Electronic Load
S
+S
-
DVM -
+
-
+
Electronic Load
b) CV Test Setup with 6.6kW Load Resistor
S
+S
-
DVM -
+
Note: Start with switch closed, take full load reading,
open switch and take no load reading.
6.6kW Load
Resistor
Figure 2-1. Constant Voltage (CV) Test Setup

Verification 13
Table 2-4. Constant Voltage (CV) Tests
Action
Normal Result
Voltage Programming and Readback Accuracy
This test verifies that the voltage programming, GPIB readback (GPIB system power supplies only), and front panel display
functions are within specifications. With system power supplies, values read back over the GPIB should be the same as
those displayed on the front panel.
1
Turn off the power supply and connect a DVM across +S and -S
(see Fig. 2-1).
2
Turn on the power supply with no load and program the output for 0 volts
and maximum programmable current (see Table 2-2).
CV annunciator on. Output current near
0.
3
Record voltage readings at DVM and on front panel display.
Readings within specified Low Voltage
limits.
4
Program voltage to full scale (see Table 2-2).
5
Record voltage readings of DVM and on front panel display.
Readings within specified High Voltage
limits.
CV Load Effect
This test measures the change in output voltage resulting from a change in output current from full-load to no-load.
1
Turn off the power supply and connect a DVM across +S and -S
(see Fig. 2-1).
2
Turn on the power supply and program the current to its maximum
programmable value and the voltage to its full-scale value (see Table 2-2).
3
Adjust the load to produce full-scale current (see Table 2-2) as shown on
the front panel display.
CV annunciator is on. If it is not, adjust
the load to slightly reduce the output
current until the annunciator comes on.
4
Record voltage reading of the DVM.
5
Adjust load to draw 0 amperes (open load). Record voltage reading of the
DVM.
6
Check test result.
The difference between the DVM
readings in steps 4 and 5 are within the
specified Load Effect limits.
CV Source Effect
This test measures the change in output voltage resulting from a change in ac line voltage from its minimum to maximum
value within the line voltage specifications.
1
Turn off the power supply and connect the ac power input through a
variable-voltage transformer.
2
Set the transformer to the nominal ac line voltage. Connect the DVM
across +S and -S (see Fig. 2-1).
3
Turn on the power supply and program the current to its maximum
programmable value and the voltage to its full-scale value (see Table 2-2).

14 Verification
Table 2-4. Constant Voltage (CV) Tests (continued)
Action
Normal Result
CV Source Effect (cont)
4
Adjust the load to produce full-scale current (see Table 2-2) as shown on
the front panel display.
CV annunciator is on. If it is not, adjust
the load to slightly reduce the output
current until the annunciator comes on.
5
Adjust the transformer to decrease the ac input voltage to the low- line
condition (174Vac or 191Vac). Record the output voltage reading of the
DVM.
6
Adjust the transformer to increase the ac input voltage to the high-line
condition (220Vac or 250Vac). Record the output voltage reading on the
DVM.
7
Check test result.
The difference between the DVM
readings in steps 5 and 6 are within the
specified Source Effect limits.
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. This test measures CV PARD, specified as the rms and peak-to-peak output
voltages over the frequency range of 20Hz to 20MHz.
1
Turn off the power supply and connect an a-c coupled oscilloscope across
the + and -output terminals (see Fig. 2-1). Set the oscilloscope bandwidth
limit to 20MHz (30MHz for the Keysight 54504A) and use an RF tip on
the oscilloscope probe.
2
Turn on the power supply and program the current to its maximum
programmable value and the voltage to its full-scale value (see Table 2-2).
3
Adjust the load to produce full-scale current (see Table 2-2) as shown on
the front panel display.
CV annunciator is on. If it is not, adjust
the load to slightly reduce the output
current until the annunciator comes on.
4
Record the amplitude of the waveform.
Amplitude is within the specified PARD
Peak-to-Peak limits.
5
Replace the oscilloscope connection with an ac rms voltmeter.
6
Record the reading obtained in Step 5.
Amplitude is within the specified PARD
rms limits.
Transient Recovery Time
This test measures the time required for the output voltage to return to within 100mV of its final value following a 50%
change in output load current. Measurements are made on both the unloading transient (from full load to 1/2 load) and the
loading transient (from 1/2 load to full load).
1
Turn off the power supply and connect an oscilloscope across +S and -S
(see Fig. 2-1).
2
Turn on the power supply and program the current to its maximum
programmable value and the voltage to its full-scale value (see Table 2-2).

Verification 15
Table 2-4. Constant Voltage (CV) Tests (continued)
Action
Normal Result
Transient Recovery (cont)
3
Program the Electronic Load as follows:
Operating mode to constant current.
Input load current to 1/2 the supply's full rated output current.
Transient current level to the supply's full rated output current.
Transient generator frequency = 100Hz.
Transient generator duty cycle = 50%.
4
Turn on the transient and adjust the oscilloscope to display response
waveform.
See Fig. 2-2.
5
Measure both the loading and unloading transients by triggering the
oscilloscope on both the negative and positive slopes of the transient.
Record the voltage level obtained at the 900-s interval .
Specified voltage level is reached within
900s.
Figure 2-2. Transient Response Waveform
Constant Current (CC) Tests
Test Setup
Connect the appropriate current monitoring resistor (see Table 2-l) as shown in Figure 2-3. The accuracy of the resistor
must be as specified in the table.
Test Procedures
The test procedures are given in Table 2-5. The tests are independent and may be performed in any order. The CC tests are:
Current Programming and Readback Accuracy.
CC Load Effect.
CC Source Effect.

16 Verification
a) CC Test Setup with 6.6kW Electronic Load
S
+S
-
DVM -
+
-
+
Electronic Load
S
+S
-
DVM -
+
6.6kW Load
Resistor
+
-
Power Supply
Current Monitor
Resistor
*
Current Monitor
Resistor
* Note: Series power source required for CC Load Regulation Test, allows
UUT to operate at 0 volts and electronic load to operate at its
minimum input voltage specification. Voltage source must always
be in CV mode. UUT must be in CC mode for all CC tests.
b) CC Test Setup with 6.6kW Load Resistor
Note: Start with switch closed, take reading at 0 output voltage.
Open switch and take full load reading.
UUT must be in CC mode for all CC tests.
Figure 2-3. CC Load Effect Test Setup

Verification 17
Table 2-5. Constant Current (CC) Tests
Action
Normal Result
Current Programming and Readback Accuracy
This test verifies that the current programming and readback are within specification.
1
Turn off the power supply and connect the current monitoring resistor as
shown in Fig. 2-3. Connect a DVM across the resistor .
2
Turn on the power supply and program the output for 5 volts and 0
amperes.
3
Short the load.
4
Observe the DVM voltage reading. Divide this by the resistance of the
current monitor resistor. Record the result as the Low Current value.
Value within specified Low Current
limits.
5
Record the front panel display readback.
Value within specified readback limits.
6
Program output current to full scale (see Table 2-2).
7
Repeat Steps 4 and 5.
Both current readings within specified
High Current and readback limits.
CC Load Effect
This test measures the change in output current resulting from a change in load from full-load voltage to a short circuit. It is
recommended that you use averaged readings for Steps 5 and 6 of this test (see Averaging AC Measurements at the end of
this chapter).
Note: Refer to Figure 2-3. If you are using Keysight N3306A electronic loads, a series DC power source is required to
supply the minimum 3 volt input required by the Keysight N3306A electronic loads. The series DC source must be capable
of 3VDC at a current level that is greater than the output current of the supply being tested. A switch can be used in
place of the series supply if the electronic loads are used in place of a load resistor as shown in Fig. 2-3(b).
1
Turn off the power supply and connect a DVM across the current
monitoring resistor (see Fig. 2-3).
2
Turn on the power supply and program the current to its full scale value
and the voltage to its maximum programmable value (see Table 2-2).
3
Set the Electronic Load to CV mode and its voltage to full scale as
indicated on its front panel display. Set the series supply for 3VDC and a
current greater than that being tested. Series source should be in CV mode.
Power supply output current is full scale
and its CC annunciator is on. If not,
reduce the Electronic Load voltage
slightly until the annunciator comes on.
4
Observe the DVM reading. Divide this by the resistance of the current
monitoring resistor to obtain the output current. Record the result.
You may want to use an averaged
reading for this measurement.
5
Program the Electronic Load input to 3 volts or short the Electronic Load
input and repeat Step 5.
You may want to use averaged reading
for this measurement.
6
Check the result.
The difference between the current
readings taken in Step 5 and Step 6 must
be within specified “Load Effect” limits
(see Table 2-2).