Keysight EDU36311A User manual

Service Guide
EDU36311A
Triple Output
Programmable
DC Power Supply

Notices 4
Copyright Notice 4
Manual Part Number 4
Edition 4
Published by 4
Warranty 4
Technology Licenses 4
U.S. Government Rights 5
Third Party Licenses 5
Waste Electrical and Electronic Equipment (WEEE) 5
Declarations of Conformity 5
Safety Information 6
1 Service and Maintenance 7
Specifications and Characteristics 8
General Information 8
Types of service available 8
Obtaining repair service (worldwide) 8
Repackaging for shipment 8
Cleaning and handling 8
Troubleshooting 9
Self-Test Procedures 9
Replacing the Power-Line Fuse 10
User Replaceable Parts 10
Battery Replacement 10
Replacing the Battery 10
Disassembly 12
Removing the front panel 12
Removing/Installing the knob 15
Installing the strap handle 15
2 Verification and Adjustments 16
Performance Verification 17
Recommended test equipment 17
Test considerations 17
Measurement techniques 18
Setup for most tests 18
Constant Voltage (CV) verification 19
CV load and line regulation 20
Constant Current (CC) verification 24
Test Record Forms 27
Test record form - Keysight EDU36311A 27
Calibration Adjustment Procedures 29
Closed–case electronic calibration 29
Calibration interval 29
Calibration adjustment process 29
Calibration security 29
Calibration count 30
Calibration message 31
Saving calibration data 31
Calibration auto save 31
Calibration procedure 31
2Keysight EDU36311A Service Guide

Save the calibration data 32
Keysight EDU36311A Service Guide 3

Notices
Copyright Notice
© Keysight Technologies 2021
No part of this manual may be reproduced in any form or by any means (including electronic storage and retrieval or
translation into a foreign language) without prior agreement and written consent from Keysight Technologies as
governed by United States and international copyright laws.
Manual Part Number
EDU36311-90014
Edition
Edition 1, January 2021
Published by
Keysight Technologies
Bayan Lepas Free Industrial Zone
11900 Bayan Lepas, Penang
Malaysia
Warranty
THE MATERIAL CONTAINED IN THIS DOCUMENT IS PROVIDED “AS IS,” AND IS SUBJECT TO BEING CHANGED,
WITHOUT NOTICE, IN FUTURE EDITIONS. FURTHER, TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE
LAW, KEYSIGHT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, WITH REGARD TO THIS MANUAL
AND ANY INFORMATION CONTAINED HEREIN, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. KEYSIGHT SHALL NOT BE LIABLE FOR ERRORS
OR FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES IN CONNECTION WITH THE FURNISHING, USE, OR
PERFORMANCE OF THIS DOCUMENT OR OF ANY INFORMATION CONTAINED HEREIN. SHOULD KEYSIGHT AND
THE USER HAVE A SEPARATE WRITTEN AGREEMENT WITH WARRANTY TERMS COVERING THE MATERIAL IN THIS
DOCUMENT THAT CONFLICT WITH THESE TERMS, THE WARRANTY TERMS IN THE SEPARATE AGREEMENT
SHALL CONTROL.
Technology Licenses
The hardware and/or software described in this document are furnished under a license and may be used or copied
only in accordance with the terms of such license.
4Keysight EDU36311A Service Guide

U.S. Government Rights
The Software is “commercial computer software,” as defined by Federal Acquisition Regulation (“FAR”) 2.101.
Pursuant to FAR 12.212 and 27.405-3 and Department of Defense FAR Supplement (“DFARS”) 227.7202, the U.S.
government acquires commercial computer software under the same terms by which the software is customarily
provided to the public. Accordingly, Keysight provides the Software to U.S. government customers under its
standard commercial license, which is embodied in its End User License Agreement (EULA), a copy of which can be
found at http://www.keysight.com/find/sweula. The license set forth in the EULA represents the exclusive authority
by which the U.S. government may use, modify, distribute, or disclose the Software. The EULA and the license set
forth therein, does not require or permit, among other things, that Keysight: (1) Furnish technical information
related to commercial computer software or commercial computer software documentation that is not customarily
provided to the public; or (2) Relinquish to, or otherwise provide, the government rights in excess of these rights
customarily provided to the public to use, modify, reproduce, release, perform, display, or disclose commercial
computer software or commercial computer software documentation. No additional government requirements
beyond those set forth in the EULA shall apply, except to the extent that those terms, rights, or licenses are explicitly
required from all providers of commercial computer software pursuant to the FAR and the DFARS and are set forth
specifically in writing elsewhere in the EULA. Keysight shall be under no obligation to update, revise or otherwise
modify the Software. With respect to any technical data as defined by FAR 2.101, pursuant to FAR 12.211 and
27.404.2 and DFARS 227.7102, the U.S. government acquires no greater than Limited Rights as defined in FAR
27.401 or DFAR 227.7103-5 (c), as applicable in any technical data.
Third Party Licenses
Portions of this software are licensed by third parties including open source terms and conditions. For more
information, please contact Keysight support, www.keysight.com/find/assist.
Waste Electrical and Electronic Equipment (WEEE)
This product complies with the WEEE Directive) marketing requirement. The affixed product label (see below)
indicates that you must not discard this electrical/electronic product in domestic household waste.
Product Category: With reference to the equipment types in the WEEE directive Annex 1, this product is classified as
“Monitoring and Control instrumentation” product. Do not dispose in domestic household waste.
To return unwanted products, contact your local Keysight office, or see
about.keysight.com/en/companyinfo/environment/takeback.shtml for more information.
Declarations of Conformity
Declarations of Conformity for this product and for other Keysight products may be downloaded from the Web. Go
to https://regulations.about.keysight.com/DoC/default.htm. You can then search by product number to find the
latest Declaration of Conformity.
Keysight EDU36311A Service Guide 5

Safety Information
A CAUTION notice denotes a hazard. It calls attention to an operating procedure, practice, or the like that, if not correctly per-
formed or adhered to, could result in damage to the product or loss of important data. Do not proceed beyond a CAUTION notice
until the indicated conditions are fully understood and met.
A WARNING notice denotes a hazard. It calls attention to an operating procedure, practice, or the like that, if not correctly per-
formed or adhered to, could result in personal injury or death. Do not proceed beyond a WARNING notice until the indicated con-
ditions are fully understood and met.
6Keysight EDU36311A Service Guide

1 Service and Maintenance
Specifications and Characteristics
General Information
Troubleshooting
Self-Test Procedures
To Replace the Power-Line Fuse
User Replaceable Parts
Battery Replacement
Disassembly
This chapter provides the specifications and service information on
cleaning, troubleshooting, repair, and replaceable parts of the
EDU36311A. This chapter also explains how to assemble and
disassemble the EDU36311A.
Keysight EDU36311A Service Guide 7

Specifications and Characteristics
For the characteristics and specifications of the EDU36311A programmable DC power supply, refer to the data-
sheet at https://www.keysight.com/us/en/assets/3120-1003/data-sheets/EDU36311A-Triple-Output-
Bench-Power-Supply.pdf
General Information
Types of service available
If your instrument fails during the warranty period, Keysight Technologies will repair or replace it under the terms of
your warranty. After your warranty expires, Keysight offers repair services at competitive prices. You also have the
option to purchase a service contract that extends the coverage after the standard warranty expires.
Obtaining repair service (worldwide)
To obtain service for your instrument, contact your nearest Keysight Technologies Service Center. They will arrange
to have your unit repaired or replaced, and can provide warranty or repair–cost information where applicable. Ask
the Keysight Technologies Service Center for shipping instructions, including what components to ship. Keysight
recommends that you retain the original shipping carton for return shipments.
Repackaging for shipment
Ensure the following to ship the unit to Keysight for service or repair:
– Attach a tag to the unit identifying the owner and indicating the required service or repair. Include the model
number and full serial number.
– Place the unit in its original container with appropriate packaging material.
– Secure the container with strong tape or metal bands.
– If the original shipping container is unavailable, use a container that will ensure at least 10 cm (4 in.) of
compressible packaging material around the entire instrument. Use static-free packaging materials.
Keysight suggests that you always insure your shipments.
Cleaning and handling
Cleaning
To prevent electrical shock, disconnect the instrument from AC mains power and disconnect all test leads before
cleaning. Clean the outside of the instrument using a soft, lint-free, cloth slightly dampened with water.
– Do not use detergent or solvents.
– Do not attempt to clean internally.
8Keysight EDU36311A Service Guide

If required, contact a Keysight Technologies Sales and Service office to arrange for proper cleaning to ensure that
safety features and performance are maintained.
Electrostatic Discharge (ESD) precautions
Almost all electrical components can be damaged by electrostatic discharge (ESD) during handling. Component
damage can occur at electrostatic discharge voltages as low as 50 V.
The following guidelines will help prevent ESD damage during service operations:
– Disassemble instruments only in a static-free work area.
– Use a conductive work area to reduce static charges.
– Use a conductive wrist strap to reduce static charge accumulation.
– Minimize handling.
– Keep replacement parts in original static-free packaging.
– Remove all plastic, foam, vinyl, paper, and other static-generating materials from the immediate work area.
Troubleshooting
Before troubleshooting or repairing the instrument, make sure the failure is in the instrument rather than any
external connections. Also make sure that the instrument was accurately calibrated within the last year (see
Calibration Adjustment Procedures > Calibration Interval for details).
Perform the following verifications if the unit is inoperative:
– Verify that the ac power cord is connected to the power supply.
– Verify that the front-panel power switch is depressed.
–Verify that the correct power-line fuse is installed. Refer to EDU36311A User's Guide for details.
– Verify the power-line voltage setting.
Self-Test Procedures
A power-on self-test occurs automatically when you turn on the power supply. This limited test assures you that the
power supply is operational.
Press Utilities >Instr. Setup >Self Test to perform the complete self-test of the power supply. It takes approximate
2 seconds for the self-test to complete.
You can also perform a complete self-test from the remote interface, see Programming Guide for details.
– If the self-test is successful, "Self Test Passed" is displayed on the front panel.
–If the self-test fails, " " is displayed on the front panel. Press Utilities >Help >Error to record the error code
and message and contact Keysight support if necessary.
– If the self-test is successful, this indicates a high chance that the power supply is operational.
Keysight EDU36311A Service Guide 9

Replacing the Power-Line Fuse
Refer to EDU36311A User's Guide for details.
User Replaceable Parts
You can find the instrument support part list at Keysight's Test & Measurement Parts Catalog
http://www.keysight.com/find/parts.
Battery Replacement
SHOCKHAZARD
Only qualified, service-trained personnel who are aware of the hazards involved should remove instrument
covers. Always disconnect the power cable and any external circuits before removing the instrument
cover.Some circuits are active and have power for a short time even when the power switch is turned off.
The internal battery powers the real-time clock. The primary function of the clock it to provide a time stamp for the
internal file system. If the battery fails, the clock and time stamp function will not be available. No other instrument
functions are affected.
Under normal use at room temperature, the lithium battery has a life expectancy between seven and ten years. Note
that battery life will be reduced if the instrument is stored for a prolonged period at temperatures above 40 degrees
Celsius.
The battery type is Panasonic CR 2032.
Replacing the Battery
1. Remove the instrument front panel. See Removing the front panel.
2. The battery is located at the main board.
3. Press out the small spring clip. Use a flat-bladed plastic screwdriver and carefully pry up on the side of the bat-
tery.
10 Keysight EDU36311A Service Guide

4. Install the new battery. Make sure that the positive side (+) is facing up. Place the battery under the small spring
(see red circle below) and push down on the opposite end of the battery (see red arrow below) to seat the bat-
tery.
5. Reassemble the front panel when finished.
6. Reset the date and time.
Properly dispose of the old battery in accordance with local laws and regulations.
Keysight EDU36311A Service Guide 11

Disassembly
Tools required
Items Torque value
T25 Torx driver 21 in.lbs
T20 Torx driver 9.0 in.lbs
T10 Torx driver 7 in.lbs
Removing the front panel
Steps Instructions Visual
1. On the top panel, remove two screws (M5x10) with T25 Torx driver from
the strap handle.
Then, remove the plastic cap and strap handle from the instrument.
2. On the bottom panel, remove the rubber foot.
Remove four screws (M4x12) with T20 Torx driver from the rubber foot.
Then, remove the rubber foot from the instrument.
3. Remove two screws (M3x6) with T10 Torx driver that holds the front
panel and the chassis cover.
4. On the rear panel, remove three screws (M3x6) with T10 Torx driver.
5. Pull out the chassis cover.
12 Keysight EDU36311A Service Guide

Steps Instructions Visual
6. Remove four screws (M3x6) from both side of the front panel.
7. Remove four screws (M3x6) from the bottom of the rear chassis.
8. Remove six screws (M3x6) from the metal handle support.
9. Remove three screws (M3x6) from the rear panel board.
10. Lift up the metal handle support.
11. Open the clip and remove the rear panel board from the metal handle
support.
Keysight EDU36311A Service Guide 13

Steps Instructions Visual
12. Before pulling out the front panel, place the unit at the
side of table with the front panel foot position at the
outer side of the table edge. See image (A).
This is to avoid power switch from being knocked off
during the front panel disassembly. See image (B).
Pull out the front panel.
13. Disconnect all the cables from the main board.
14. The front panel is removed.
15. To install back the front panel, perform the above steps in reverse order.
14 Keysight EDU36311A Service Guide

Removing/Installing the knob
Steps Instructions Visual
1. Pull out the knob to remove the knob from the front panel.
2. To install back the knob, push the knob back in the shaft.
NOTE: Make sure to follow the shaft orientation before pushing the
knob.
Installing the strap handle
Steps Instructions Visual
1. Insert the stainless steel belt into the PVC strap.
2. Insert the stainless steel gaskets to both side of the stainless steel
belt.
3. Cover both side with the plastic cap.
4. Secure both side of the strap handle with two screws (M5x10) using
T25 Torx driver.
Keysight EDU36311A Service Guide 15

2 Verification and Adjustments
Performance Verification
Test Record Forms
Calibration Adjustment Procedures
This chapter contains the performance verification procedures which
verify that the EDU36311A is operating within its published
specifications. This chapter also provides information on adjustments
performed after a performance verification fails.
16 Keysight EDU36311A Service Guide

Performance Verification
Performance verification ensures that the instrument performs within the specifications stated in the data sheet
(https://www.keysight.com/us/en/assets/3120-1003/data-sheets/EDU36311A-Triple-Output-Bench-Power-
Supply.pdf)
Recommended test equipment
The test equipments recommended for the performance verification and adjustment procedures are listed below. If
the exact instrument is not available, use the accuracy requirements shown to select substitute calibration
standards.
Type Specification Recommended model
Digital multimeter Readout: 8 1/2 digits Basic DC Accuracy: 0.0008% Keysight 3458A or equivalent
Current monitor 15 A (0.1 Ω), TC = 4 ppm/°C Guildline 9230A-15R
Electronic load 150 V, 5 A minimum, with transient capability and a slew rate of
833 kA/s or better.
Keysight N3300A mainframe, with
N330xA modules
LAN / USB controller N/A PC with Keysight Connection Expert
loaded
Oscilloscope Sensitivity: 1 mV; Bandwidth Limit: 20 MHz Probe: 1:1 with RF
tip
Keysight DSOX1202A oscilloscope or
equivalent
Terminations 1 – 50 Ω BNC termination
2 – 50 Ω, ≥ 1/8 W resistor
N/A
Variable voltage transformer or
AC source
Adjustable to highest rated input voltage range. Power: 500 VA Keysight 6813C or equivalent
Test considerations
– Ensure that the calibration ambient temperature is stable and between 20 °C and 30 °C.
– Ensure ambient relative humidity is less than 80%.
– Allow a 1-hour warm-up period before verification or calibration.
– Keep cables as short as possible, consistent with the impedance requirements.
– Performance verification and calibration procedure must be performed through front panel output.
The tests should be performed by qualified personnel. During performance verification tests, hazardous voltages
may be present at the outputs of the power supply.
Keysight EDU36311A Service Guide 17

Measurement techniques
Digital Multimeter
To ensure that the values read by the multimeter during both the verification procedure and the calibration
procedure are not affected by the instantaneous measurement of the AC peaks of the output current ripple, make
several DC measurements and average them.
Current-monitoring resistor
The 4-terminal current shunt is used to eliminate output current measurement error caused by voltage drops in the
load leads and connections. It has special current-monitoring terminals inside the load connection terminals.
Connect the voltmeter 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 should be used to connect, disconnect, or short the load resistor. For most tests, an
electronic load can be used. The electronic load is considerably easier to use than load resistors, but it may not be
fast enough to test transient recovery time and may be too noisy for the noise (PARD) tests.
Fixed load resistors may be used in place of a variable load, with minor changes to the test procedures. Also, if
computer controlled test setups are used, the relatively slow (compared to computers and system voltmeters)
settling times and slew rates of the power system may have to be taken into account. "Wait" statements can be used
in the test program if the test system is faster than the power system.
Setup for most tests
This setup is used for most tests and it requires the DMM, electronic load, and power supply being verified. Some
wire is also required for connection between instruments. A LAN or USB cable is needed for readback data. The
18 Keysight EDU36311A Service Guide

DMM measures the power supply output, and the electronic load draws current from the power supply. The
accuracy of the current monitoring resistor must be 0.01% or better, which should include any self-heating effects.
Constant Voltage (CV) verification
Voltage programming and readback accuracy
These tests verify that the voltage programming and the LAN or USB readback functions are within specifications.
Note that the readback values over the remote interface should be identical to those displayed on the front panel,
but with maximum resolution.
1. Turn off the power supply using the AC line switch.
2. Connect a DMM between the (+) and (–) terminals of the output.
3. If you are using a computer to control the power supply, connect a LAN or USB cable from the power supply to
the PC.
4. Turn on the power supply using the AC line switch.
Voltage programming accuracy
Step Front Panel SCPI
5. Set the instrument settings as described in the test record form
under the Voltage Programming and Readback. See Test
Record Forms for details.
VOLT 6, (@<channel>); CURR 5, (@<channel>)
This is an example for 6 V, 5 A output.
6. Enable the output by pressing ON key for the selected output. OUTP ON, (@<channel>)
7. The output status should be CV and the output current should be close to zero.
8. Record the voltage measured by the DMM and verify whether it is within the limits calculated.
Voltage readback accuracy
Step Front Panel SCPI
9. MEAS:VOLT? (@<channel>)
This is an example for 6 V, 5 A output.
10. Record the voltage returned by the SCPI command query via Keysight Connection Expert, and verify whether it
is within the limits calculated.
Keysight EDU36311A Service Guide 19

CV load and line regulation
These tests verify that the voltage variation due to load or line variation are within specifications.
CV load regulation
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 using the AC line switch.
2. Connect the power supply output with a DMM and an electronic load.
3. If you are using a PC to control the power supply, connect a LAN or USB cable from the power supply to the PC.
4. Turn on the power supply using the AC line switch.
5. Set the power supply settings as described in the test record form under “CV Load Regulation”. See the Test
Record Forms under “CV Load Regulation” for details. Enable the output.
6. Operate the electronic load in constant current mode and set its current to the value in the test record form
under “CV Load Regulation”. See the Test Record Forms under Test Description of “CV Load Regulation” for
details. Check that the front panel CV annunciator of the power supply remains lit. If it turns to CC or UR,
adjust the load so that the output current drops slightly until the CV annunciator lights up. Record the output
voltage reading on the DMM as Vload.
7. Operate the electronic load in open mode (input off). Record the output voltage reading on the DMM imme-
diately as Vnoload.
8. Take the difference between the DMM readings in steps 6 and 7 that is the CV load regulation (Vload –
Vnoload). The difference of the readings during the immediate change should be within the specification limits.
20 Keysight EDU36311A Service Guide