Keysight U1231A, U1232A,
and U1233A Handheld
Digital Multimeter
Service Guide
Notices
CAUTION
WARNING
Copyright Notice
© Keysight Technologies 2011 – 2017
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
U1231-90035
Edition
Edition 10, June 30, 2017
Printed in:
Printed in Malaysia
Published by:
Keysight Technologies
Bayan Lepas Free Industrial Zone,
11900 Penang, Malaysia
Technology Licenses
The hard ware 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.
Declaration of Conformity
Declarations of Conformity for this
product and for other Keysight
products may be downloaded from the
Web. Go to http://www.keysight.com/
go/conformity. You can then search by
product number to find the latest
Declaration of Conformity.
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.
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.
Safety Information
A CAUTION notice denotes a hazard. It
calls attention to an operating
procedure, practice, or the like that, if
not correctly performed 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 performed or adhered to,
could result in personal injury or death.
Do not proceed beyond a WARNING
notice until the indicated conditions are
fully understood and met.
2 Keysight U1231A, U1232A, and U1233A Service Guide
Safety Symbols
CAT III
600 V
The following symbols on the instrument and in the documentation indicate
precautions that must be taken to maintain safe operation of the instrument.
DC (Direct current or voltage)
AC (Alternating current or voltage)
Caution, risk of danger (refer to this
manual for specific Warning or Caution
information)
Equipment protected throughout by
double insulation or reinforced
insulation
Earth (ground) terminal
Category III 600 V overvoltage
protection
Keysight U1231A, U1232A, and U1233A Service Guide 3
Safety Considerations
CAUTION
Read the information below before using this instrument.
The following general safety precautions must be observed during all phases of
operation, service, and repair of this instrument. Failure to comply with these
precautions or with specific warnings elsewhere in this manual violates safety
standards for design, manufacture, and intended use of the instrument. Keysight
Technologies assumes no liability for the customer’s failure to comply with these
requirements.
– Disconnect circuit power and discharge all high-voltage capacitors
before testing resistance, continuity, diodes, or capacitance.
– Use the proper terminals, function, and range for your measurements.
– This device is for use at altitudes of up to 2,000 m.
– Never measure voltage when current measurement is selected.
– Always use the specified battery type. The power for the meter is
supplied with four standard AAA 1.5 V batteries. Observe the correct
polarity markings before you insert the batteries to ensure proper
insertion of the batteries in the meter.
– You are advised to use low leakage batteries when changing to new
batteries. Please remember to remove the batteries when the meter is not
in use for a long period of time. Warning on the risk of battery leakage.
– To avoid damage to the instrument from battery leakage:
– Always remove dead batteries immediately.
– Always remove the batteries and store them separately if the
instrument is not going to be used or is being stored for a long period
of time.
4 Keysight U1231A, U1232A, and U1233A Service Guide
WARNING
– Do not use the meter if it is damaged. Before you use the meter, inspect
the case. Look for cracks or missing plastic. Pay particular attention to
the insulation surrounding the connectors.
– Inspect the test leads for damaged insulation or exposed metal. Check
the test leads for continuity. Replace damaged test leads before you use
the meter.
– Do not operate the meter around explosive gas, vapor, or wet
environments.
– Do not apply more than the rated voltage (as marked on the meter)
between terminals, or between terminal and earth ground.
– Never use the meter in wet conditions or when there is water on the
surface. If the meter is wet, ensure that the meter is dried only by trained
personnel.
– Before use, verify the meter's operation by measuring a known voltage.
– When measuring current, turn off the circuit power before connecting the
meter in the circuit. Remember to place the meter in series with the
circuit.
– When servicing the meter, use only the specified replacement parts.
– Use caution when working above 60 V DC, 30 V AC rms, or 42.4 V peak.
Such voltages pose a shock hazard.
Keysight U1231A, U1232A, and U1233A Service Guide 5
– Do not use the VZ
(low input impedance) function to measure
LOW
voltages in circuits that could be damaged by this function’s low input
impedance of 3 k
Ω.
– When using the probes, keep your fingers behind the finger guards on the
probes.
– Connect the common test lead before you connect the live test lead.
When you disconnect the leads, disconnect the live test lead first.
– Remove the test leads from the meter before you open the battery cover.
WARNING
– Do not operate the meter with the battery cover or portions of the cover
removed or loosened.
– To avoid false readings, which may lead to possible electric shock or
personal injury, replace the battery as soon as the low battery indicator
appears and flashes.
6 Keysight U1231A, U1232A, and U1233A Service Guide
Measurement Category
The U1231A, U1232A, and U1233A has a safety rating of CAT III, 600 V.
Measurement CAT I Measurements performed on circuits not directly
connected to the AC mains. Examples are measurements on circuits not derived
from the AC mains and specially protected (internal) mains-derived circuits.
Measurement CAT II Measurements performed on circuits directly connected
to a low-voltage installation. Examples are measurements on household
appliances, portable tools, and similar equipment.
Measurement CAT III Measurements performed in the building installation.
Examples are measurements on distribution boards, circuit- breakers, wiring,
including cables, bus-bars, junction boxes, switches, socket outlets in the fixed
installation, and equipment for industrial use, and some other equipment
including stationary motors with permanent connection to the fixed installation.
Measurement CAT IV Measurements performed at the source of the
low-voltage installation. Examples are electricity meters and measurements on
primary overcurrent protection devices and ripple control units.
Keysight U1231A, U1232A, and U1233A Service Guide 7
Environmental Conditions
NOTE
This U1231A, U1232A, and U1233A is designed for indoor use and in an area with
low condensation. The table below shows the general environmental requirements
for this instrument.
Environmental conditions Requirements
Operating temperature Full accuracy from –10 °C to 55 °C
Operating humidity
Storage temperature –40 °C to 60 °C
Altitude Up to 2000 meters
Pollution degree Pollution degree II
The U1231A/U1232A/U1233A Handheld Digital Multimeter complies with the
following safety and EMC requirements:
– EN 61010-1 (IEC 61010-1:2001) for CAT III 600 V
– ANSI/UL 61010-1:2004
– CAN/CSA-C22.2 No. 61010-1-04
– Commercial limits compliance with EN61326-1
Full accuracy up to 80% RH (relative
humidity) for temperature up to 30 °C,
decreasing linearly to 50% RH at 55 °C
8 Keysight U1231A, U1232A, and U1233A Service Guide
Regulatory Markings
The CE mark is a registered trademark
of the European Community. This CE
mark shows that the product complies
with all the relevant European Legal
Directives.
ICES/NMB-001 indicates that this ISM
device complies with the
Canadian ICES-001.
Cet appareil ISM est conforme a la
norme NMB-001 du Canada.
The CSA mark is a registered
trademark of the Canadian
Standards Association.
The RCM mark is a registered
trademark of the Spectrum
Management Agency of Australia.
This signifies compliance with the
Australia EMC Framework regulations
under the terms of the Radio
Communication Act of 1992.
This instrument complies with the
WEEE Directive (2002/96/EC) marking
requirement. This affixed product label
indicates that you must not discard
this electrical or electronic product in
domestic household waste.
This symbol indicates the time period
during which no hazardous or toxic
substance elements are expected to
leak or deteriorate during normal use.
Forty years is the expected useful life
of the product.
Keysight U1231A, U1232A, and U1233A Service Guide 9
Waste Electrical and Electronic Equipment (WEEE) Directive 2002/96/EC
This instrument complies with the WEEE Directive (2002/96/EC) marking
requirement. This affixed product label indicates that you must not discard this
electrical or electronic product in domestic household waste.
Product Category:
With reference to the equipment types in the WEEE directive Annex 1, this
instrument is classified as a “Monitoring and Control Instrument” product.
The affixed product label is as shown below.
Do not dispose in domestic household waste.
To return this unwanted instrument, contact your nearest Keysight Service Center,
or visit http://about.keysight.com/en/companyinfo/environment/takeback.shtml
for more information.
Sales and Technical Support
To contact Keysight for sales and technical support, refer to the support links on
the following Keysight websites:
– www.keysight.com/find/u1230dmm
(product-specific information and support, software and
documentation updates)
– www.keysight.com/find/assist
(worldwide contact information for repair and service)
10 Keysight U1231A, U1232A, and U1233A Service Guide
Table of Contents
Safety Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Safety Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Measurement Category . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Environmental Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Regulatory Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Waste Electrical and Electronic Equipment (WEEE) Directive
2002/96/EC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Product Category: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Sales and Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
1 Calibration Procedures
Keysight Calibration Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Closed case calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Calibration interval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Other recommendations for calibration . . . . . . . . . . . . . . . . . . . . . .19
Recommended Test Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Basic Operating Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Backlight test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Display test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Calibration Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Test Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Performance Verification Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Calibration Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Unsecuring the Instrument for Calibration . . . . . . . . . . . . . . . . . . . . . .29
To unsecure the instrument from the front panel . . . . . . . . . . . . . . .29
To change the calibration security code . . . . . . . . . . . . . . . . . . . . . .31
To reset the calibration security code to its factory default . . . . . . .32
Using the Front Panel for Adjustments . . . . . . . . . . . . . . . . . . . . . . . . .34
Adjustment considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Adjustment procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Keysight U1231A, U1232A, and U1233A Service Guide 11
Valid adjustment input values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Functional tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Exiting the adjustment mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Calibration Count . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Calibration Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
2Service and Maintenance
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Checking the Fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Fuse Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Returning the Instrument for Service . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Replaceable Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
To order replaceable parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Types of Service Available . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Extended service contracts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Obtaining Repair Service (Worldwide) . . . . . . . . . . . . . . . . . . . . . . . . . . 54
12 Keysight U1231A, U1232A, and U1233A Service Guide
List of Figures
Figure 1-1 LCD display screen . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Figure 1-2 SECU display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Figure 1-3 Calibration security code display . . . . . . . . . . . . . . . . .29
Figure 1-4 Calibration security code operation . . . . . . . . . . . . . . .30
Figure 1-5 CSEC display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Figure 1-6 Factory default calibration security code display . . . .31
Figure 1-7 SErn display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Figure 1-8 Calibration security code display . . . . . . . . . . . . . . . . .32
Figure 1-9 Calibration reference value display . . . . . . . . . . . . . . .35
Figure 1-10 Vsense functional test . . . . . . . . . . . . . . . . . . . . . . . . .41
Figure 2-1 Testing the fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
Figure 2-2 Replacing the fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . .50
Keysight U1231A, U1232A, and U1233A Service Guide 13
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14 Keysight U1231A, U1232A, and U1233A Service Guide
List of Tables
Table 1-1 Recommended test equipment . . . . . . . . . . . . . . . . . . 20
Table 1-2 Performance verification tests . . . . . . . . . . . . . . . . . . .24
Table 1-3 Adjustment input values . . . . . . . . . . . . . . . . . . . . . . .37
Table 1-4 Calibration error codes . . . . . . . . . . . . . . . . . . . . . . . . . 44
Table 2-1 Operating checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Table 2-2 Fuse displayed readings . . . . . . . . . . . . . . . . . . . . . . . . 47
Keysight U1231A, U1232A, and U1233A Service Guide 15
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16 Keysight U1231A, U1232A, and U1233A Service Guide
Keysight U1231A, U1232A, and U1233A Handheld Digital Multimeter
Service Guide
1 Calibration Procedures
Keysight Calibration Services 18
Recommended Test Equipment 20
Basic Operating Test 21
Calibration Process 22
Test Considerations 23
Performance Verification Tests 24
Calibration Security 28
Unsecuring the Instrument for Calibration 29
Using the Front Panel for Adjustments 34
Calibration Count 43
Calibration Error Codes 44
This chapter contains procedures for verifying the instrument performance, as
well as procedures for making adjustments (calibration) where necessary.
17
1 Calibration Procedures
Keysight Calibration Services
When your instrument is due for calibration, contact your local Keysight Service
Center for recalibration. See “Types of Service Available” on page 53 for more
information on the various calibration services offered.
Closed case calibration
The U1231A/U1232A/U1233A handheld digital multimeter features closed-case
electronic calibration. In other words, no internal electro-mechanical adjustment
is required. This instrument calculates correction factors based on the input
reference signals you feed into it during the calibration process. The new
correction factors are stored in nonvolatile EEPROM memory until the next
calibration (adjustment) is performed.
The contents of this nonvolatile EEPROM memory will not change even when the
power is switched off.
Calibration interval
The instrument should be calibrated on a regular interval determined by the
measurement accuracy requirements of your application.
A one-year interval is adequate for most applications.
Accuracy specifications are warranted only if calibration is performed at regular
intervals. Accuracy specifications are not warranted beyond the one-year
calibration interval.
Keysight does not recommend extending calibration intervals beyond two years
for any application.
18 Keysight U1231A, U1232A, and U1233A Service Guide
Other recommendations for calibration
Specifications are only guaranteed within the specified period from the last
calibration. Keysight recommends that readjustment should always be performed
at whatever calibration interval you select. This will ensure that the instrument
remains within its specifications until the next calibration. This calibration criterion
provides the best long-term stability.
During performance verification tests, only the performance data is collected;
these tests do not guarantee that the instrument will remain within the specified
limits. The tests are only for identifying which functions need adjustment.
Please refer to the “Calibration Count” on page 43 and verify that all adjustments
have been performed.
Calibration Procedures 1
Keysight U1231A, U1232A, and U1233A Service Guide 19
1 Calibration Procedures
Recommended Test Equipment
The test equipment recommended for the performance verification and
adjustment procedures is listed below in Tab le 1-1 . If the exact instrument is not
available, substitute with another calibration standard of equivalent accuracy.
Tab le 1- 1 Recommended test equipment
Application Recommended equipment Recommended accuracy requirements
DC voltage Fluke 5520A <20% of the instrument accuracy specification
DC current Fluke 5520A <20% of the instrument accuracy specification
Resistance Fluke 5520A <20% of the instrument accuracy specification
AC voltage Fluke 5520A <20% of the instrument accuracy specification
AC current Fluke 5520A <20% of the instrument accuracy specification
Frequency Fluke 5520A <20% of the instrument accuracy specification
Capacitance Fluke 5520A <20% of the instrument accuracy specification
Diode Fluke 5520A <20% of the instrument accuracy specification
Fluke 5520A <20% of the instrument accuracy specification
Temperature
Short Pomona MDP-S —
TM Electronics KMPC1MP
(K-Type thermocouple extension)
—
20 Keysight U1231A, U1232A, and U1233A Service Guide
Basic Operating Test
A
u
t
o
T
r
i
H
o
l
d
g
L
o
g
The tests listed below are used to test the basic operability of the instrument.
Repair is required if the instrument fails the any of the tests.
– “Backlight test”
– “Display test”
Backlight test
Power-on the multimeter and press the key once. Check that the LCD
backlight is turned on. Press the key again to turn the LCD backlight off.
Next, press and hold the key for more than 1 second. Check that the LED
flashlight is turned on. Press and hold the key for more than 1 second again to
turn the LED flashlight off.
Display test
Press and hold the key while turning the rotary switch to any other position
(OFF to ON). Check that all the annunciators are displayed in the LCD. Compare
the display with the example shown in Figure 1-1. Press any key to exit this mode.
Calibration Procedures 1
Figure 1-1 LCD display screen
Keysight U1231A, U1232A, and U1233A Service Guide 21
1 Calibration Procedures
Calibration Process
1 Prior to performing the verification tests, see the “Test Considerations” on
page 23.
2 Perform the verification tests to characterize the multimeter; see “Performance
Verification Tests” on page 24.
3 Unsecure the multimeter for calibration; see “Calibration Security” on page 28.
4 Prior to performing the adjustments, see the “Adjustment considerations” on
page 34.
5 Perform the adjustment procedure; see “Adjustment procedure” on page 35.
6 Secure the multimeter against unauthorized calibration; see “Exiting the
adjustment mode” on page 42. Ensure that the multimeter has quit the
adjustment mode and is turned off.
7 Record the new security code and calibration count in the multimeter's
maintenance records.
22 Keysight U1231A, U1232A, and U1233A Service Guide
Test Considerations
For optimum performance, all procedures should comply with the following
recommendations:
– The performance verification test or adjustment should be performed under a
laboratory condition, where the ambient temperature can be controlled.
– Ensure that the calibration ambient temperature is stable and is between 18 °C
and 28 °C. Ideally the calibration should be performed at 23 °C ± 1 °C.
– Ensure that the ambient relative humidity is less than 80%.
– The instrument should be in the laboratory environment for at least 1 hour prior.
– Allow a warm-up period of 3 minutes.
– Use shielded twisted-pair PTFE-insulated cables to reduce settling and noise
errors. Keep the input cables as short as possible.
Calibration Procedures 1
Keysight U1231A, U1232A, and U1233A Service Guide 23
1 Calibration Procedures
NOTE
Hz
Performance Verification Tests
Use the performance verification tests to verify the measurement performance of
the instrument. The performance verification tests use the instrument's
specifications listed in the U1231A/U1232A/U1233A User's Guide (available for
download at www.keysight.com/find/hhTechLib).
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 multimeter fails the performance verification tests, adjustment or repair is
required.
Ensure that you have read the “Test Considerations” on page 23 before running
the performance verification tests.
Tab le 1- 2 Performance verification tests
Step Test function Range 5520A input
1
Z
to the position.
2
ACV Turn the rotary switch
to the position.
Turn the rotary switch
LOW
600 V 30 V ±0.9 V ±0.9 V ±0.9 V
600 mV 600 mV, 45 Hz ±6.3 mV ±6.3 mV ±6.3 mV
600 mV, 1 kHz ±12.3 mV ±12.3 mV ±12.3 mV
6 V 6 V, 45 Hz ±0.063 V ±0.063 V ±0.063 V
6 V, 1 kHz ±0.123 V ±0.123 V ±0.123 V
60 V 60 V, 45 Hz ±0.63 V ±0.63 V ±0.63 V
60 V, 1 kHz ±1.23 V ±1.23 V ±1.23 V
600 V 600 V, 45 Hz ±6.3 V ±6.3 V ±6.3 V
600 V, 1 kHz ±12.3 V ±12.3 V ±12.3 V
Error from nominal 1 year
U1231A U1232A U1233A
24 Keysight U1231A, U1232A, and U1233A Service Guide
Tab le 1-2 Performance verification tests (continued)
Hz
S
h
i
f
t
E
s
c
N
u
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Calibration Procedures 1
Step Test function Range 5520A input
Error from nominal 1 year
U1231A U1232A U1233A
3
Frequency While the
9.999 kHz 1 kHz, 0.12 V ±0.003 kHz ±0.003 kHz ±0.003 kHz
rotary switch is in the
position, press the key
once.
4
DCV Turn the rotary switch
to the position.
[a]
600 mV
6 V 6 V ±0.032 V ±0.032 V ±0.032 V
600 mV ±3.2 mV ±3.2 mV ±3.2 mV
60 V 60 V ±0.32 V ±0.32 V ±0.32 V
600 V 600 V ±3.2 V ±3.2 V ±3.2 V
[a] The accuracy is specified after the Null function is used to subtract the thermal effect (by shorting the test leads) before measuring the signal.
5
Resistance Turn the
rotary switch to the
position.
600 Ω
6 kΩ
[b]
[b]
600 Ω ±5.7 Ω ±5.7 Ω ±5.7 Ω
6 kΩ ±0.057 kΩ ±0.057 kΩ ±0.057 kΩ
60 kΩ 60 kΩ ±0.57 kΩ ±0.57 kΩ ±0.57 kΩ
600 kΩ 600 kΩ ±5.7 kΩ ±5.7 kΩ ±5.7 kΩ
[c]
6 MΩ
[c]
60 MΩ
[b] The accuracy of the 600 Ω to 6 kΩ range is specified after the Null function is used to subtract the test lead resistance and thermal effect
(by shorting the test leads). Apply a 0 Ω calibrator output and allow the multimeter to settle before you press the key.
[c] The RH is specified for <60%.
6
Diode Turn the rotary
2 V 2 V 0.020 V 0.020 V 0.020 V
6 MΩ ±0.057 MΩ ±0.057 MΩ ±0.057 MΩ
60 MΩ ±0.93 MΩ ±0.93 MΩ ±0.93 MΩ
switch to the position.
Keysight U1231A, U1232A, and U1233A Service Guide 25
1 Calibration Procedures
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AUX
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Tab le 1- 2 Performance verification tests (continued)
Step Test function Range 5520A input
Error from nominal 1 year
U1231A U1232A U1233A
position.
[d]
Turn the
1000 nF 1000 nF ±21 nF ±21 nF ±21 nF
10 μF10 μF ±0.21μF±0.21μF±0.21μF
100 μF100 μF ±2.1 μF ±2.1 μF ±2.1 μF
7
Capacitance
rotary switch to the , , or
1000 μF 1000 μF ±21 μF ±21 μF ±21 μF
10 mF 10 mF ±0.21 mF ±0.21 mF ±0.21 mF
[d] The accuracy for all ranges is specified based on a film capacitor or better, and after the Null function is used to subtract the residual values
(by opening the test leads).
8
[e]
Scale
While the rotary
switch is in the or
600 mV 600 mV 3.2 mV 3.2 mV -
600 mV 600 mV, 70 Hz 6.3 mV 6.3 mV -
position, press the
key (until mV is shown on
the display).
[e] AC/DC mV measurement must be enabled prior to this step. Refer to the “Enable the AC/DC mV measurement” section of Chapter 4,
“Multimeter Setup Options” in the U1231A/U1232A/U1233A User’s Guide for further information on how to enable the AC/DC mV
measurement.
9
Temperature
the rotary switch is in the
[f]
While
–40 °C to 1372 °C 0 °C - - ± (Probe
accuracy
+ 1.0 °C)
or position, press the
key once.
[f] Ensure that the ambient temperature is stable within ±1 ºC. Ensure that the multimeter is placed in a controlled environment for at least 1
hour before you proceed to ensure that the multimeter’s internal reference junction sensor and input terminal are stabilized at the same
environment. Keep the multimeter away from any ventilation exit.
Differences in ambient compensation between the calibrator and multimeter may cause some deviations shown between the readings of
the calibrator and multimeter. Placing the multimeter close to the output terminal of the calibrator will help reduce this deviation.
Do not touch the thermocouple test lead after connecting it to the calibrator. Allow the connection to stabilize for at least another 15
minutes before performing the measurement.
Set both Fluke 5520A and multimeter to internal reference.
To perform the measurement, connect one end of the K-type thermocouple (with miniature TC connector on both ends) to the 5520A TC
output, and the other end to the multimeter via a TC-to-banana adapter. Allow at least 1 hour for the multimeter to stabilize.
26 Keysight U1231A, U1232A, and U1233A Service Guide
Tab le 1-2 Performance verification tests (continued)
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Calibration Procedures 1
Step Test function Range 5520A input
Error from nominal 1 year
U1231A U1232A U1233A
10
[g] CAUTION: Connect the calibrator to the multimeter's A and COM terminals before applying the 6 A and 10 A input.
11
[g]
DCA
Turn the rotary
switch to the position.
ACA While the rotary switch
is in the position, press
6 A 6 A - ±0.063 A ±0.063 A
10 A 10 A - ±0.13 A ±0.13 A
6 A 6 A, 500 Hz - ±0.093 A ±0.093 A
10 A 10 A, 500 Hz - ±0.18 A ±0.18 A
the key once.
12
DCμA Turn the rotary
switch to the
60 μA 60 μA-±0.62 μA±0.62 μA
600 μA 600 μA-±6.2 μA±6.2 μA
position.
13
ACμA While the rotary
switch is in the
60 μA60 μA, 500 Hz - ±0.93 μA±0.93 μA
600 μA 600 μA, 500 Hz - ±9.3 μA±9.3 μA
position, press the key
once.
Keysight U1231A, U1232A, and U1233A Service Guide 27
1 Calibration Procedures
NOTE
Calibration Security
The calibration security code prevents accidental or unauthorized adjustments to
the instrument. When you first receive your instrument, it is secured. Before you
can adjust the instrument, you must unsecure it by entering the correct security
code (see “Unsecuring the Instrument for Calibration” on page 29).
The security code can only be changed after the instrument has been unsecured.
You can unsecure the instrument from its front panel.
The security code is set to “1234” when the instrument is shipped from the
factory. The security code is stored in nonvolatile memory, and does not change
when power has been turned off.
The security code may contain up to 4 numeric characters.
28 Keysight U1231A, U1232A, and U1233A Service Guide
Unsecuring the Instrument for Calibration
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Before you can adjust the instrument, you must unsecure it by entering the
correct security code.
The default security code is set to 1234.
– If you forget your security code, see “To reset the calibration security code to
its factory default” on page 32.
– The auto power-off (APO) feature will be disabled after you unsecure the
instrument.
To unsecure the instrument from the front panel
1 Power-on the multimeter and press the and keys simultaneously for
more that 1 second to enter the calibration security code entry mode.
2SECU is shown on the display briefly, followed by the calibration security code.
Calibration Procedures 1
Figure 1-2 SECU display
Figure 1-3 Calibration security code display
Keysight U1231A, U1232A, and U1233A Service Guide 29
1 Calibration Procedures
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Wrong security code
entered.
Correct security code entered,
multimeter enters adjustment mode.
Press .
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3 Press or to move the cursor to the right or to the left.
4 Press or to increment or decrement the digit.
5 Press when you are done.
If the correct security code is entered, PASS is shown in the display briefly,
after which the instrument will enter the adjustment mode.
If the incorrect security code is entered, an error code will appear on the
display briefly, after which the calibration security code entry mode will appear
again.
Figure 1-4 Calibration security code operation
30 Keysight U1231A, U1232A, and U1233A Service Guide
To change the calibration security code
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1 After the instrument has been unsecured, press for more than 1 second to
enter the calibration security code setting mode.
2CSEC is shown on the display briefly, followed by the factory default
calibration security code 1234.
Figure 1-5 CSEC display
Calibration Procedures 1
Figure 1-6 Factory default calibration security code display
3 Set your new calibration security code.
Press or to move the cursor to the right or to the left.
Press or to increment or decrement the digit.
4 Press to save the new calibration security code.
5 If the new calibration security code has been successfully stored, the display
will show PASS. Record down your new calibration security code and store it in
a safe location.
Keysight U1231A, U1232A, and U1233A Service Guide 31
1 Calibration Procedures
NOTE
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To reset the calibration security code to its factory default
If you have forgotten the correct calibration security code, you may follow the steps
below to reset the calibration security code to the factory default code (1234).
If you do not have a record (or have lost the record) of the security code, first try
the factory default code,
1 Before you begin, note down the last four digits of the multimeter's serial
number (located to the left of the multimeter’s flashlight, under the bumpers).
2 Power-on the multimeter and press the and keys simultaneously for
more that 1 second to enter the calibration security code entry mode.
3SECU is shown on the display briefly, followed by the calibration security code.
4 Press for more than 1 second to enter the calibration security code
reset mode. SErn is shown on the display briefly, followed by the calibration
security code.
1234 from the front panel.
Figure 1-7 SErn display
Figure 1-8 Calibration security code display
32 Keysight U1231A, U1232A, and U1233A Service Guide
Calibration Procedures 1
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5 Set the code to the same as the last four digits of the instrument's serial
number.
Press or to move the cursor to the right or to the left.
Press or to increment or decrement the digit.
6 Press to confirm the entry.
7 If the four digits entered are correct, the display will show PASS briefly. The
calibration security code is now set to the its factory default code, 1234.
If you want to enter a new security code, see “To change the calibration security
code” on page 31. Ensure that you record down the new security code.
Keysight U1231A, U1232A, and U1233A Service Guide 33
1 Calibration Procedures
NOTE
CAUTION
Using the Front Panel for Adjustments
This section describes the procedures to perform adjustments from the front panel.
To unsecure the instrument, see “To unsecure the instrument from the front panel”
on page 29. Once unsecured, the reference value will be indicated on the display.
Adjustment considerations
After each adjustment, the display shows PASS briefly. If the calibration fails,
the multimeter sounds a beep, and an error number is shown in the display
briefly. Calibration error messages are described in “Calibration Error Codes” on
page 44.
1 Allow the instrument to warm up and stabilize for 3 minutes before performing
the adjustments.
2 Check that the battery levels are at least at two bars before performing any
adjustments. This ensures that during the adjustments, the low battery
indicator does not appear.
If the low battery indicator appears, replace the batteries as soon as possible
to avoid false readings.
3 Consider the thermal effects as you are connecting the test leads to the
calibrator and handheld multimeter. It is recommended to wait for 1 minute
before you begin the calibration after connecting the test leads.
4 Before proceeding with the ambient temperature adjustment, be sure to turn
on the multimeter for at least 1 hour with the K-type thermocouple connected.
Never turn off the multimeter during an adjustment. This may delete the
calibration memory for the present function.
34 Keysight U1231A, U1232A, and U1233A Service Guide
Adjustment procedure
NOTE
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NOTE
Review the “Test Considerations” and “Adjustment considerations” before
beginning the adjustment procedures.
1 Turn the rotary switch to the respective test function position as shown in the
adjustment input values table (Ta ble 1-3 on page 37).
2 Unsecure the instrument to enter the adjustment mode. (See “Unsecuring the
Instrument for Calibration” on page 29).
While in the adjustment mode, press and simultaneously to exit the
adjustment mode.
3 The display will show the reference value of the calibration item.
Calibration Procedures 1
Figure 1-9 Calibration reference value display
4 Configure each calibration item.
5 Use the arrow keys to select the calibration range.
6 Apply the input signal shown in the Reference Value column of Table 1- 3. The
analog bar graph displays the input reading. There is no bar graph display for
temperature adjustment.
You are highly recommended to complete the adjustments in the same order as
shown in the appropriate table.
Keysight U1231A, U1232A, and U1233A Service Guide 35
1 Calibration Procedures
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NOTE
7 Use the arrow keys to enter the actual applied input values.
8 Press to start the adjustment. Cal flashes in the display to indicate that
the calibration is in progress.
9 Upon completion of each adjustment value, the display will show PASS briefly.
If the adjustment fails, the multimeter will sound a long beep and the
calibration error number appears in the display briefly. The display will then
return to the current calibration item.
If the adjustment fails, check the input value, range, function, and entered
adjustment value before repeating the adjustment steps.
10 Turn the rotary switch to the next function according to the Test Function
column shown in Table 1-3. Repeat step 3 to step 8 for each adjustment point
shown in the adjustment table.
11 Verify the adjustments using the “Performance Verification Tests” on page 24.
36 Keysight U1231A, U1232A, and U1233A Service Guide
Calibration Procedures 1
Valid adjustment input values
Adjustment can be accomplished using the following input values below.
Tab le 1-3 Adjustment input values
Test function Step Reference value Valid reference input
40.0 mV (70 Hz) 0.9 to 1.1 × Reference value
600 mV
6 V
600.0 mV (70 Hz) 0.9 to 1.1 × Reference value
600.0 mV (1 kHz) 0.9 to 1.1 × Reference value
0.600 V (70 Hz) 0.9 to 1.1 × Reference value
6.000 V (70 Hz) 0.9 to 1.1 × Reference value
ACV
60 V
600 V
Vsense
Note: Refer to the “Vsense functional test (for U1233A model only)” on page 40. Place the multimeter with the top area as close
to the signal source as possible. Ensure that the calibrator’s Earth function is turned on.
Resistance
Hi.10 10 V (55 Hz) -
Lo.30 30 V (55 Hz) -
SHORT SHor SHORT Ω/COM terminals
60 MΩ
600 kΩ 600.0 kΩ 0.9 to 1.1 × Reference value
60 kΩ 60.00 kΩ 0.9 to 1.1 × Reference value
6 kΩ 6.000 kΩ 0.9 to 1.1 × Reference value
600 Ω 600.0 Ω 0.9 to 1.1 × Reference value
6.000 V (1 kHz) 0.9 to 1.1 × Reference value
6.00 V (70 Hz) 0.9 to 1.1 × Reference value
60.00 V (70 Hz) 0.9 to 1.1 × Reference value
60.00 V (1 kHz) 0.9 to 1.1 × Reference value
60.0 V (70 Hz) 0.9 to 1.1 × Reference value
600.0 V (70 Hz) 0.9 to 1.1 × Reference value
600.0 V (1 kHz) 0.9 to 1.1 × Reference value
oPEn OPEN terminals
10.00 MΩ 0.9 to 1.1 × Reference value
Keysight U1231A, U1232A, and U1233A Service Guide 37
1 Calibration Procedures
Tab le 1- 3 Adjustment input values (continued)
Test function Step Reference value Valid reference input
SHORT SHor SHORT V/COM terminals
600 mV 600.0 mV 0.9 to 1.1 × Reference value
DCV
Diode
Capacitance
DCmV (Scale/
Transducer)
ACmV (Scale/
Transducer)
Temperature K type 0.0 °C 0 °C with ambient compensation required
Note: Ensure the multimeter is turned on and stabilized for at least 60 minutes with the K-type thermocouple connected
between the multimeter and the calibrator output terminal.
– Set the 5520A to internal reference.
– Prior to performing adjustment, connect one end of the K-type thermocouple (with miniature TC connector on both ends)
to the 5520A TC output, and the other end to a precision thermometer to verify that the source outputs the desired value.
Adjust the source accordingly if necessary.
– To perform the adjustment, connect one end of the K-type thermocouple (with miniature TC connector on both ends) to the
5520A TC output, and the other end to the multimeter via a TC-to-banana adapter. Allow at least 1 hour for the multimeter
to stabilize.
6 V 6.000 V 0.9 to 1.1 × Reference value
60 V 60.00 V 0.9 to 1.1 × Reference value
600 V 600.0 V 0.9 to 1.1 × Reference value
SHORT SHor SHORT V/COM terminals
3 V 2.000 V 0.9 to 1.1 × Reference value
OPEN oPEn OPEN terminals
100 nF 0.9 to 1.1 × Reference value
1000 nF
1000 nF 0.9 to 1.1 × Reference value
10 μF 10.00 μF 0.9 to 1.1 × Reference value
100 μF 100.0 μF 0.9 to 1.1 × Reference value
1000 μF 1000 μF 0.9 to 1.1 × Reference value
10 mF 10.00 mF 0.9 to 1.1 × Reference value
SHORT SHor SHORT V/COM terminals
600 mV 600.0 mV 0.9 to 1.1 × Reference value
30.0 mV (70 Hz) 0.9 to 1.1 × Reference value
600 mV
600.0 mV (70 Hz) 0.9 to 1.1 × Reference value
38 Keysight U1231A, U1232A, and U1233A Service Guide
Calibration Procedures 1
Tab le 1-3 Adjustment input values (continued)
Test function Step Reference value Valid reference input
OPEN oPEn OPEN terminals
DCμA
ACμA
60 μA 60.00 μA 0.9 to 1.1× Reference value
600 μA 600.0 μA 0.9 to 1.1 × Reference value
30.00 μA (70 Hz) 0.9 to 1.1 × Reference value
60 μA
60.00 μA (70 Hz) 0.9 to 1.1 × Reference value
60.0 μA (70 Hz) 0.9 to 1.1 × Reference value
600 μA
600.0 μA (70 Hz) 0.9 to 1.1 × Reference value
OPEN oPEn OPEN terminals
DCA
ACA
6 A 6.000 A 0.7 to 1.3 × Reference value
10 A 10.00 A 0.7 to 1.3 × Reference value
0.300 A (70 Hz) 0.7 to 1.3 × Reference value
6 A
6.000 A (70 Hz) 0.7 to 1.3 × Reference value
3.00 A (70 Hz) 0.7 to 1.3 × Reference value
10 A
10.00 A (70 Hz) 0.7 to 1.3 × Reference value
Keysight U1231A, U1232A, and U1233A Service Guide 39
1 Calibration Procedures
NOTE
Functional tests
Use the functional tests to verify the measurement functionality of the instrument.
Z
functional test
LOW
Use the following procedure to verify that Z
1 Connect the COM and Ω terminals of the U1252B (or equivalent) to the COM
and V terminals of the multimeter under test.
2 Turn the U1231A/U1232A/U1233A rotary switch to the position before
proceeding with the following Z
LOW
functional test.
LOW
is functional.
Step Test function Range 5520A input
1
Z
to the position.
Turn the rotary switch
LOW
600 V 2.97 kΩ ±0.702 kΩ ±0.702 kΩ ±0.702 kΩ
3 Repair is required if the multimeter fails the Z
Vsense functional test (for U1233A model only)
Use the following procedure to verify that Vsense is functional.
– Keep the multimeter away from electrical noise sources during the tests
(that is, florescent lights, dimmable lights, motors, and so on). These sources
can trigger the Vsense alert and invalidate the test.
– It may be necessary to slightly adjust the multimeter’s position for maximum
signal strength, in order to get the multimeter’s beeper to sound
continuously.
Error from nominal 1 year
U1231A U1232A U1233A
functional test.
LOW
40 Keysight U1231A, U1232A, and U1233A Service Guide
Calibration Procedures 1
CAUTION
Dual banana plug
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1 Connect a dual banana plug to the output voltage terminals of the calibrator.
2 Hold the multimeter so that the top of the multimeter is vertically and
horizontally centered and in contact with the banana plug’s Hi terminal.
Do not touch the dual banana plug with your hand while the calibrator
output is turned on.
Figure 1-10 Vsense functional test
Step Test function Range 5520A input Vsense alert status
1
Vsense Turn the rotary
switch to the position.
Hi.SE
Output off No alert
10 V, 55 Hz Alert on
Press and hold for more
than 1 second.
Lo.SE
5 V, 55 Hz No alert
15 V, 55 Hz Alert on
3 Adjustment or repair is required if the multimeter fails any of the Vsense
functional test.
Keysight U1231A, U1232A, and U1233A Service Guide 41
1 Calibration Procedures
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Exiting the adjustment mode
1 Remove all the shorting plugs and connectors from the instrument.
2 Record the new Calibration Count.
3 Press and simultaneously to exit the Adjustment Mode.
4 Power off and on again. The instrument will then be secured.
42 Keysight U1231A, U1232A, and U1233A Service Guide
Calibration Count
NOTE
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You can query the instrument to determine how many adjustments have been
performed.
The multimeter was calibrated before it left the factory. You are recommended
to record the initial value of the calibration count once you receive the
multimeter.
The count value increases by one for each calibration point, from 0000 up to the
maximum of 19999. After the maximum count, the calibration count will reset to
0. The calibration count can be read from the front panel after the multimeter has
been unsecured.
1 In adjustment mode, press and hold for more than 1 second to view the
calibration count. The calibration count value is shown on the display.
2 Take note of the calibration count to keep track of the number of calibrations
that have been performed.
3 Press and hold for more than 1 second again to exit the calibration
count mode.
Calibration Procedures 1
Keysight U1231A, U1232A, and U1233A Service Guide 43
1 Calibration Procedures
Calibration Error Codes
The following errors indicate failures that may occur during a calibration.
Tab le 1- 4 Calibration error codes
Code Descriptions
Er002 Calibration error: secure code invalid
Er003 Calibration error: serial number code invalid
Er004 Calibration error: calibration aborted
Er005 Calibration error: value out of range
Er006 Calibration error: signal measurement out of range
Er007 Calibration error: frequency out of range
Er008 EEPROM write failure
44 Keysight U1231A, U1232A, and U1233A Service Guide
Keysight U1231A, U1232A, and U1233A Handheld Digital Multimeter
Service Guide
2 Service and Maintenance
Troubleshooting 46
Checking the Fuse 47
Fuse Replacement 49
Returning the Instrument for Service 51
Replaceable Parts 52
Types of Service Available 53
Obtaining Repair Service (Worldwide) 54
This chapter will help you troubleshoot a failing instrument. It also describes how
to obtain repair services and lists the replaceable assemblies.
45
2 Service and Maintenance
WARNING
Troubleshooting
To avoid electrical shock, do not perform any service unless you are qualified
to do so.
If the instrument fails to operate, check the batteries and the test leads. Replace
them if necessary. And if the instrument still does not function, check the
operating procedures in this manual. When servicing, use only the specified
replacement parts.
The table below will assist you in identifying some basic malfunctions.
Tab le 2- 1 Operating checklist
Malfunction Identification
No display when powered ON using the rotary
switch
No beeper tone ✔ Verify that the beeper is enabled in the multimeter’s Setup mode.
✔ Verify the batteries health and replace batteries as necessary.
Failed on current measurement (U1232A or
U1233A models only)
Failed on remote control
✔ Verify the fuses health and replace the fuses as necessary (see “Checking
the Fuse” on page 47).
✔ Verify the optical side of of the IR-USB cable connected to multimeter —
the Keysight logo should be facing up.
✔ Verify the baud rate, data bit, stop bit, and parity settings in the
multimeter’s Setup mode. (Default values are 9600, 8, 1, and none.)
✔ Verify that the driver for the IR-USB interface is installed.
46 Keysight U1231A, U1232A, and U1233A Service Guide
Checking the Fuse
This procedure is applicable for U1232A and U1233A models only.
It is recommended that you check the fuse(s) of the multimeter before using it.
Follow the instructions below to test the fuses inside the multimeter.
1 Turn the rotary switch to the position and connect the red test lead to the Ω
input terminal.
2 To test the fuse, place the tip of the test probe on the top half of A input
terminal. Ensure that the probe tip touches the metal inside the A input
terminal, as shown in Figure 2-1.
3 Observe the reading on the instrument's display. Refer to Table 2-2 below for
the possible readings that could appear. Replace the fuse when OL is
displayed.
Tab le 2-2 Fuse displayed readings
Service and Maintenance 2
Current input terminal Part number Fuse rating
2110-1402 11 A/1000 V ≈0.0 Ω OL
Displayed readings
Fuse healthy Replace fuse
Keysight U1231A, U1232A, and U1233A Service Guide 47
2 Service and Maintenance
13
2
4
Figure 2-1 Testing the fuse
48 Keysight U1231A, U1232A, and U1233A Service Guide
Fuse Replacement
NOTE
CAUTION
No recalibration is required after replacing the fuse.
The current input terminals of your multimeter are fuse protected. The fuses are
located next to the battery compartment.
The terminal is protected by a 10 × 38 mm, 11 A/1000 V, 30 kA fast-acting fuse
(Fuse 1).
If you are certain that the fuse is faulty, replace it with one of the same size and
rating.
Before you proceed with the fuse replacement, remove all cable connections
to the terminals and ensure that the rotary switch is at the OFF position.
1 Open the battery cover. Lift the tilt stand and loosen screws with a suitable
Phillips screwdriver and remove the battery cover.
2 Locate the faulty fuse. The fuse is located at the bottom of the batteries (see
Figure 2-2).
Gently remove the defective fuse by prying one end of the fuse with a flathead
screwdriver and removing it out of the fuse bracket. Replace a new fuse of the
same size and rating into the center of the fuse holder.
Service and Maintenance 2
3 Close the batter cover. Place the battery cover back in its original position and
tighten the screws.
Keysight U1231A, U1232A, and U1233A Service Guide 49
2 Service and Maintenance
1
2
3
Figure 2-2 Replacing the fuse
50 Keysight U1231A, U1232A, and U1233A Service Guide
Returning the Instrument for Service
NOTE
Before shipping your instrument for repair or replacement, Keysight recommends
that you acquire the shipping instructions from the Keysight Technologies Service
Center. A clear understanding of the shipping instructions is necessary to secure
your product for shipment.
1 Attach a tag to the instrument with following information:
– Name and address of owner
– Instrument model number
– Instrument serial number
– Description of the service required or failure indications
2 Remove all accessories from the instrument. Do not include accessories unless
they are associated with the failure symptoms.
3 Place the instrument in its original container with appropriate packaging
material for shipping.
If the original shipping container is not available, place your unit in a container
which will ensure at least 4 inches of compressible packaging material around all
sides for the instrument. Use static-free packaging materials to avoid additional
damage to your unit.
Service and Maintenance 2
Keysight suggests that you always insure your shipments.
Keysight U1231A, U1232A, and U1233A Service Guide 51
2 Service and Maintenance
Replaceable Parts
This section contains information for ordering replacement parts for your
instrument. You can find the instrument support part list in the Keysight's Test &
Measurement Parts Catalog at http://www.keysight.com/find/parts
The parts lists include a brief description of each part with applicable Keysight
part number.
To order replaceable parts
You can order replaceable parts from Keysight using the Keysight part number.
Note that not all parts listed are available as field-replaceable parts.
To order replaceable parts from Keysight, do the following:
1 Contact your nearest Keysight Sales Office or Service Center.
2 Identify the parts by the Keysight part number shown in the support parts list.
3 Provide the instrument model number and serial number.
52 Keysight U1231A, U1232A, and U1233A Service Guide
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.
Extended service contracts
Many Keysight products are available with optional service contracts that extend
the covered period after the standard warranty expires. If you have such a service
contract and your instrument fails during the covered period, Keysight
Technologies will repair or replace it in accordance with the contract.
Service and Maintenance 2
Keysight U1231A, U1232A, and U1233A Service Guide 53
2 Service and Maintenance
Obtaining Repair Service (Worldwide)
To obtain service for your instrument (in-warranty or under service contract),
contact your nearest Keysight Technologies Service Center. They will arrange to
have your unit repaired or replaced, and can provide warranty information where
applicable.
To obtain warranty, service, or technical support information you can contact
Keysight Technologies at one of the following telephone numbers:
– In the United States: (800) 829-4444
– In Europe: 31 20 547 2111
– In Japan: 0120-421-345
Or use our Web link for information on contacting Keysight worldwide:
www.keysight.com/find/assist
Or contact your Keysight Technologies Representative.
Before shipping your instrument, ask the Keysight Technologies Service Center to
provide shipping instructions, including what components to ship. Keysight
recommends that you retain the original shipping carton for use in such
shipments.
54 Keysight U1231A, U1232A, and U1233A Service Guide
This information is subject to change
without notice. Always refer to the
Keysight website for the latest
revision.
© Keysight Technologies 2011 – 2017
Edition 10, June 30, 2017
Printed in Malaysia
*U1231-90035*
U1231-90035
www.keysight.com
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