Keysight Technologies EDU34450A User manual

Service Guide
EDU34450A
5½ Digit Digital Multimeter

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 9
Troubleshooting 9
Troubleshooting procedure 10
Checking the current input fuse 10
Self-Test Procedures 10
Self-Test Error 11
Replacing the Power-Line Fuse 12
Replacing the Current Input Fuse 12
User Replaceable Parts 12
Battery Replacement 12
Replacing the Battery 12
2 Performance Verification 14
Performance Verification 15
Recommended Test Equipment 16
Test Considerations 17
Input connections 17
Quick Performance Check 18
Performance Verification Tests 18
Zero offset verification 19
Gain verification 20
AC voltage verification test 25
AC current verification test 27
Capacitance verification test 28
3 Calibration Adjustments 29
Calibration Adjustment 30
Closed–case electronic calibration 30
Keysight Technologies calibration services 30
Calibration interval 30
Time required for calibration 30
Automating calibration procedures 30
Calibration Adjustment Process 31
Calibration Security 31
2Keysight EDU34450A Service Guide

Calibration Count 32
Calibration Message 32
Calibration Error 33
Calibration Adjustment Procedure 33
Zero adjustments 33
Gain adjustments 34
DC voltage gain adjustment procedure 35
DC current gain adjustment procedure 36
AC voltage gain adjustment procedure 37
AC current gain adjustment procedure 38
Ohms gain adjustment procedure 39
Capacitance gain adjustment procedure 40
Frequency gain adjustment procedure 41
Finishing the adjustments 41
Keysight EDU34450A 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
EDU34450-90014
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 EDU34450A 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 EDU34450A 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 EDU34450A Service Guide

1 Service and Maintenance
Specifications and Characteristics
General Information
Troubleshooting
Self-Test Procedures
Self-Test Error
Replacing the Power-Line Fuse
Replacing the Current Input Fuse
User Replaceable Parts
Battery Replacement
This chapter provides the specifications and service information on
cleaning, troubleshooting, repair, and replaceable parts of the
EDU34450A. This chapter also explains how to assemble and
disassemble the EDU34450A.
Keysight EDU34450A Service Guide 7

Specifications and Characteristics
For the characteristics and specifications of the EDU34450A digital multimeter, refer to the datasheet at
https://www.keysight.com/us/en/assets/3120-1002/data-sheets/EDU34450A-5-5-Digit-Dual-Display-
Digital-Multimeter.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.
– Remove all accessories from the instrument. Do not include accessories unless they are associated with the fail-
ure symptoms.
– 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.
8Keysight EDU34450A Service Guide

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.
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 multimeter and AC line power.
– Verify that the front-panel power switch is depressed.
–Verify that the correct power-line fuse is installed. Refer to EDU34450A User's Guide for details.
– Verify the power-line voltage setting.
Perform the following verifications if the unit fail self test:
– Remove all test connections to the multimeter and run the self–test again.
NOTE: Errors may be induced by AC signals present on the multimeter input terminals during self–test. Long
test leads can act as an antenna causing pick–up of AC signals.
Perform the following verifications if the unit's current input is inoperative:
– Verify the current input fuse. See Checking the current input fuse.
Keysight EDU34450A Service Guide 9

Troubleshooting procedure
Malfunction Identification
Failed current measurement Verify the fuse condition and replace the fuse as necessary.
Failed to power on the instrument when power is
supplied
–Verify the power line fuse condition and replace the power line fuse
as necessary.
–Ensure that correct voltage rating is selected on the instrument.
Failed to update firmware –Verify that driver is installed correctly.
–Verify that the I/O configuration and information entered in the
Keysight Basic Firmware Update Utility is correct.
–Ensure that no power or I/O connection lost during update.
–Ensure instrument boot into bootloader mode when updating the
firmware through recovery mode.
No beeper tone Verify that the beeper is enabled in User Settings.
No keyclick tone Verify that the key click is enabled in User Settings.
No display Press any key to exit "display off" mode.
Checking the current input fuse
1. Press [Ω2W] to access 2W resistance measurement.
2. Connect a red test lead between Ω and 3 A input terminal.
3. Observe the resistance reading on the display. Replace the fuse if the resistance reading is > 0.3 Ω.
NOTE: Refer to Current Input Fuse Replacement in EDU34450A User's Guide for details.
Self-Test Procedures
Remove all test connections to the multimeter before performing self-test.
A power-on self-test occurs automatically when you turn on the multimeter. This limited test assures you that the
multimeter is operational.
Press [Shift]>[Store/Recall] | Utility >Instr. Setup >Self Test to perform the complete self-test of the multimeter.
It takes less than 10 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 Success" is displayed briefly on the front panel.
–If the self-test fails, " " is displayed on the front panel. Press [Shift]>[Store/Recall] | Utility >Help >Error
View to record the error code and message, contact Keysight support if necessary.
– If the self-test is successful, this indicates a high confidence that the multimeter is operational.
10 Keysight EDU34450A Service Guide

Self-Test Error
The EDU34450A self test (see the *TST? command) performs a series of tests on the instrument hardware. Any
failure of these tests will generate a SCPI error number -330, with additional test failure information. Refer to the
Keysight EDU34450A Programming Guide for more information.
On the remote interface, a self–test failure will generate SCPI error –330 and a supplemental message indic-
ating one of the test numbers shown below. On the front panel, only the failing test is shown.
The form of this error message is as follows:
-330,"Self-test failed; <test# - testname>"
Where test# is the number of the test that failed (range 550 - 617) and testname describes the test. Here is an
example of a test failure message:
-330,"Self-test failed; 617 - RTC Oscillation failed"
The following is the list of test numbers and descriptions:
Error Code Error Messages
550 3.3V power lost
551 5.0V power lost
552 12V power lost
600 I/O processor failed self test
601 M/B eeprom failed
602 M/B flash failed
603 M/B ASIC failed
604 DC low path zero test failed
605 DC high path zero test failed
606 AC path zero test failed
611 EEPROM load failed
612 EEPROM checksum failed
615 Invalid MAC address
616 Front panel does not respond
617 RTC Oscillation failed
Keysight EDU34450A Service Guide 11

Replacing the Power-Line Fuse
Refer to Power Line Fuse Replacement in EDU34450A User's Guide for details.
Replacing the Current Input Fuse
Refer to Current Input Fuse Replacement in EDU34450A 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 remain powered 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 usage 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 °C.
The battery type is CR 2032.
Replacing the Battery
Tools required
Items Torque value
T10 Torx screwdriver 0.56 Nm
Flat plastic screwdriver -
1. Remove four screws as shown below.
2. Remove the rear panel.
12 Keysight EDU34450A Service Guide

3. Remove nine screws from the chassis. Then, remove the chassis from the front panel.
4. The battery is located on the main board.
5. Unlatch the small spring clips (see red circle below). Use a flat-bladed plastic screwdriver and carefully pry up on
the side of the battery.
6. Install the new battery. Make sure that the positive side (+) is facing up. Place the battery under the small spring
clips (see red circle below), then push down on the opposite end of the battery to secure the battery (see red
arrow below).
7. Assemble the rear panel when finished.
8. Reset the date and time.
Properly dispose of the used battery in accordance with local laws and regulations.
Keysight EDU34450A Service Guide 13

2 Performance Verification
Performance Verification
Recommended Test Equipment
Test Considerations
Quick Performance Check
Performance Verification Tests
This chapter contains the performance verification procedures which
verify that the EDU34450A is operating within its published
specifications.
14 Keysight EDU34450A 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/3120-1002/data-sheets/EDU34450A-5-5-Digit-Dual-Display-Digital-
Multimeter.pdf)
You can perform four different levels of performance verification tests:
–Self test A series of internal verification tests that give a high confidence that the instrument is operational.
–Quick verification A combination of the internal self tests and selected verification test.
–Performance verification tests An extensive set of tests that are recommended as an acceptance test when
you first receive the instrument or after performing adjustments.
–Zero offset verification
–DC voltage gain verification
–DC current gain verification
–Ohms gain verification
–Frequency gain verification
–AC voltage verification
–AC current verification
–Optional verification tests Tests not performed with every calibration. Perform these tests to verify additional
specifications or functions of the instrument.
–Capacitance verification
Keysight EDU34450A Service Guide 15

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.
Application Recommended equipment Recommended accuracy requirement
Zero calibration Fluke 5522A or Keysight 34172B DMM calibration short
DC voltage Fluke 5522A 1/5 instrument 1 year specification
DC current Fluke 5522A 1/5 instrument 1 year specification
Resistance Fluke 5522A 1/5 instrument 1 year specification
AC voltage Fluke 5522A 1/5 instrument 1 year specification
AC current Fluke 5522A 1/5 instrument 1 year specification
Frequency Fluke 5522A 1/5 instrument 1 year specification
Capacitance Fluke 5522A 1/5 instrument 1 year specification
16 Keysight EDU34450A Service Guide

Test Considerations
Errors may be induced by AC signals present on the input leads during a self test. Long test leads can also act as an
antenna causing pick-up of AC signals.
For optimum performance, all procedures should comply with the following recommendations:
– Ensure that the calibration ambient temperature is stable between 18 °C and 28 °C. Ideally the calibration
should be performed at 23 °C ±1 °C.
– Ensure ambient relative humidity is less than 60%.
– Allow a 90 minutes warm-up period for performance verification tests and two hours warm-up period for
calibration with a shorting plug connected to the HI and LO input terminals.
– Use shielded twisted pair PTFE-insulated cables to reduce settling and noise errors. Keep the input cables as
short as possible.
– Connect the input cable shields to earth ground. Except where noted in the procedures, connect the calibrator
LO source to earth ground at the calibrator. It is important that the LO to earth ground connection be made at
only one place in the circuit to avoid ground loops.
The instrument is capable of making very accurate measurements, special care must be taken to ensure that the
calibration standards and test procedures do not introduce additional errors. Ideally, the standards used to verify
and adjust the instrument should be an order of magnitude more accurate than each instrument range full- scale
error specification.
For DC voltage, DC current, and resistance gain verification measurements, ensure that the calibrator’s “0” output is
accurate. Null the offset for each range of the measuring function being verified.
Input connections
Test connections to the instrument are best accomplished using the dual banana plug with copper wire shorted
between two terminals for low-thermal offset measurement. Shielded, twisted-pair, PTFE insulated interconnect
cables with minimum length are recommended between the calibrator and the multimeter. Cable shields should be
earth ground referenced. This configuration is recommended for optimal noises and settling time performance
during calibration.
Keysight EDU34450A Service Guide 17

Quick Performance Check
The quick performance check is a combination of internal self test and an abbreviated performance test (specified by
the letter Q in the performance verification tests). This test provides a simple method to achieve high confidence in
the instrument’s ability to functionally operate and meet specifications. These tests represent the absolute minimum
set of performance checks recommended following any service activity. Auditing the instrument’s performance for
the quick check points (designated by a Q) verifies performance for “normal” accuracy drift mechanisms. This test
does not check for abnormal component failures.
To perform the quick performance check, do the following:
– Perform a self test. Refer to Self-Test Procedures.
– Perform only the performance verification tests indicated in the following tables with the letter Q.
If the instrument fails the quick performance check, adjustment or repair is required.
Performance Verification Tests
The performance verification tests are recommended as acceptance tests when you first receive the instrument. The
acceptance test results should be compared against the one year test limits. After acceptance, you should repeat
the performance verification tests at every calibration interval.
If the instrument fails performance verification, adjustment or repair is required.
Adjustment is recommended at every calibration interval. If adjustment is not made, guardbanding at no more than
80% of the specifications, as the verification limits.
Ensure that you have read Test Considerations before running the performance verification tests.
18 Keysight EDU34450A Service Guide

Zero offset verification
This test is used to check the zero offset performance of the instrument. Verification checks are only performed for
those functions and ranges with unique offset calibration constants. Measurements are checked for each function
and range as described in the procedure below.
Zero offset verification test
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. Connect the 5-pin Keysight 34172B DMM calibration short to the input terminals, where short is indicated.
(see Input connections).
2. Select each function and range in the order shown in the table below. Make a measurement and observe the
result. Compare measurement results to the appropriate test limits shown below:
Step Function[a] Range Quick check Error from nominal
one year
Open DC current 10 mA
100 mA
1 A
3 A
Q
±1.5 μA
±7 μA
±0.15 mA
±0.21 mA
Open Capacitance 10 nF
100 nF
1 μF
10 μF
100 μF
1 mF
10 mF
±0.15 nF (typ)
±0.5 nF
±5 nF
±0.05 μF
±0.5 μF
±5 μF
±0.05 mF
Short DC Voltage 100 mV
1 V
10 V
100 V
1000 V
Q
±8 μV
±50 μV
±0.5 mV
±5 mV
±50 mV
Short Resistance 100 Ω
1 kΩ
10 kΩ
100 kΩ
1 MΩ
10 MΩ
100 MΩ
Q
±10 mΩ[b]
±80 mΩ[b]
±500 mΩ[b]
±5 Ω
±50 Ω
±500 Ω
±5 kΩ
[a] Select 5½ digit (slow mode) measurement resolution, not applicable for Capacitance.
[b] Specifications are for 4W or 2W resistance function using the Null math function enabled to eliminate lead resistance. Without Null, add 0.2 Ω additional error to 2W resistance
function.
typ = Typical performance
Q = Quick performance verification test points
Keysight EDU34450A Service Guide 19

Gain verification
This test checks the full-scale reading accuracy of the instrument. Verification checks are performed only for
functions and ranges with unique gain calibration constants.
DC voltage gain verification test
Configuration: DC Voltage (CONFigure[:VOLTage][:DC])
1. Connect the calibrator to the front panel HI and LO input terminals as shown above.
2. Select each function and range in the order shown below. Provide the input voltage indicated below.
3. Make a measurement and observe the result. Compare measurement results to the appropriate test limits
shown in the table. (Be certain to allow for appropriate source settling.)
Input Function[a] Range Quick check Error from nominal
one year
100 mV DC voltage 100 mV ±26 μV
–100 mV 100 mV ±26 μV
1 V 1 V ±0.2 mV
–1 V 1 V Q ±0.2 mV
10 V 10 V ±3 mV
100 V 100 V Q ±30 mV
1000 V 1000 V ±0.32 V
[a] Select 5½ digit (slow mode) measurement resolution
Q = Quick performance verification test points
20 Keysight EDU34450A Service Guide