Agilent Technologies U1270 Series User manual

Agilent Technologies
Agilent U1270 Series
Handheld Digital
Multimeters
Service Guide

II U1270 Series Service Guide
Notices
© Agilent Technologies, Inc. 2010–2013
No part of this manual may be reproduced in
any form or by any means (including elec-
tronic storage and retrieval or translation
into a foreign language) without prior agree-
ment and written consent from Agilent
Technologies, Inc. as governed by United
States and international copyright laws.
Manual Part Number
U1271-90020
Edition
Tenth Edition, November 21, 2013
Agilent Technologies, Inc.
5301 Stevens Creek Blvd.
Santa Clara, CA 95051 USA
Warranty
The material contained in this document is
provided “as is,” and is subject to change,
without notice, in future editions. Further,
to the maximum extent permitted by the
applicable law, Agilent disclaims all war-
ranties, either express or implied, with
regard to this manual and any information
contained herein, including but not limited
to the implied warranties of merchantabil-
ity and fitness for a particular purpose.
Agilent shall not be liable for errors or for
incidental or consequential damages in
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information contained herein. Should Agi-
lent and the user have a separate written
agreement with warranty terms covering
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Technology Licenses
The hardware and or software described in
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puter Software Documentation).
Safety Notices
CAUTION
A CAUTION notice denotes a haz-
ard. It calls attention to an operat-
ing procedure, practice, or the likes
of that, if not correctly performed
or adhered to, could result in dam-
age to the product or loss of impor-
tant data. Do not proceed beyond a
CAUTION notice until the indicated
conditions are fully understood and
met.
WARNING
A WARNING notice denotes a
hazard. It calls attention to an
operating procedure, practice, or
the likes of that, if not correctly
performed or adhered to, could
result in personal injury or death.
Do not proceed beyond a WARN-
ING notice until the indicated
conditions are fully understood
and met.

U1270 Series Service Guide III
Safety Symbols
The following symbols on the instrument and in the documentation
indicate precautions which must be taken to maintain safe operation of
the instrument.
Direct current (DC) Caution, risk of electric shock
Alternating current (AC) Caution, risk of danger (refer to this manual
for specific Warning or Caution information)
Both direct and alternating current Category III 1000 V overvoltage protection
Earth (ground) terminal Category IV 600 V overvoltage protection
Equipment protected throughout by double
insulation or reinforced insulation
CAT III
1000 V
CAT IV
600 V

IV U1270 Series Service Guide
Safety Considerations
Read the information below before using this multimeter. The descriptions
and instructions in this manual apply to the Agilent U1271A, U1272A,
U1273A, and U1273AX Handheld Digital Multimeters (hereafter referred to
as the multimeter). The U1273A and U1272A models appear in all
illustrations.
CAUTION
•Disconnect circuit power and discharge all high-voltage capacitors
before measuring 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 3000 m.
•Never measure voltage when current measurement is selected.
•Always use the specified battery type. The power for the meter is
supplied with four 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.
•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.
WARNING
• Do not use the multimeter if it is damaged. Before you use the
multimeter, 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 multimeter.
• Do not operate the multimeter around explosive gas, vapor, or wet
environments.

U1270 Series Service Guide V
WARNING
• Do not apply more than the rated voltage (as marked on the
multimeter) between terminals, or between the terminal and
earth ground. Before use, verify the multimeter's operation by
measuring a known voltage.
• Never use the multimeter in wet conditions or when there is
water on the surface. If the multimeter is wet, ensure that the
multimeter is dried only by trained personnel.
• When measuring current, turn off the circuit power before
connecting the multimeter in the circuit. Remember to place the
multimeter in series with the circuit.
• Apply caution when working above 60 VDC, 30 VAC (RMS), or
42.4 VPEAK. Such voltages pose a shock hazard.
• Be aware of the presence of hazardous voltage before using the
Low Pass Filter (LPF) function for voltage measurement. Voltages
measured are usually greater than what are indicated on the
multimeter as the voltages with higher frequencies have been
filtered through the LPF function.
• Do not use the ZLOW (low input impedance) function (U1272A,
U1273A, and U1273AX only) to measure voltages in circuits that
could be damaged by this function’s low input impedance of 2 kΩ.
• 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 multimeter before you open the
battery cover. Do not operate the multimeter with the battery
cover or portions of the cover removed or loosened. When
servicing the multimeter, use only the specified replacement
parts.
• 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.

VI U1270 Series Service Guide
Environmental Conditions
This instrument 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
Temperature
• Operating condition
•U1271A/U1272A/U1273A: –20 °C to 55 °C
•U1273AX: –40 °C to 55 °C (using Lithium
batteries)
• Storage condition
•–40°C to 70 °C
Humidity
• Operating condition
•Maximum: 80% RH at 40 °C
(non-condensing)
•Minimum: 50% RH at 40 °C
(non-condensing)
• Storage condition
•Up to 95% RH at 40 °C (non-condensing)
Altitude Up to 3000 m
Pollution degree Pollution degree II
NOTE
The U1270 Series Handheld Digital Multimeters comply with the following safety
and EMC requirements:
•Safety
•EN/IEC 61010-1:2001
•ANSI/UL 61010-1:2004
•CAN/CSA-C22.2 No. 61010-1-04
•EMC
•IEC61326-1:2005/EN61326-1:2006
•Canada: ICES/NMB-001: Issue 4, June 2006
•Australia/New Zealand: AS/NZS CISPR 11:2004

U1270 Series Service Guide VII
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.
The C-tick 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.
ICES/NMB-001 indicates that this ISM
device complies with the Canadian
ICES-001. Cet appareil ISM est
confomre a la norme NMB-001 du
Canada.
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.
The CSA mark is a registered
trademark of the Canadian Standards
Association.
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.

VIII U1270 Series Service Guide
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 Agilent Service
Centre, or visit
www.agilent.com/environment/product
for more information.

U1270 Series Service Guide IX
Declaration of Conformity (DoC)
The Declaration of Conformity (DoC) for this instrument is available on the
Agilent Web site. You can search the DoC by its product model or
description at the Web address below.
http://regulations.corporate.agilent.com/DoC/search.htm
NOTE
If you are unable to search for the respective DoC, please contact your
local Agilent representative.

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U1270 Series Service Guide XI
Table of Contents
1 Calibration Procedures
Calibration Overview 18
Closed-case calibration 18
Agilent calibration services 18
Calibration interval 19
Adjustment is recommended 19
Recommended Test Equipment 20
Basic Operating Test 22
Backlight test (U1271A/U1272A only) 22
Display test 22
Current terminal input test 23
Calibration Process 25
Test Considerations 26
Performance Verification Tests 27
Calibration Security 37
Unsecuring the Instrument for Calibration 38
To unsecure the instrument from the front panel 38
To change the calibration security code 39
To reset the calibration security code to its factory default 40
Using the Front Panel for Adjustments 42
Adjustment considerations 42
Valid adjustment input values 43
Adjustment procedure 47
Exiting the adjustment mode 48
Calibration Count 49
Calibration Error Codes 50

XII U1270 Series Service Guide
2 Service and Maintenance
Troubleshooting 52
Checking the Fuse 53
Fuse Replacement 57
Returning the Instrument for Service 61
Replaceable Parts 62
To order replaceable parts 62
Types of Service Available 63
Extended service contracts 63
Obtaining Repair Service (Worldwide) 64

U1270 Series Service Guide XIII
List of Figures
Figure 1-1 U1273A/U1273AX OLED display screen 22
Figure 1-2 U1271A/U1272A LCD screen 23
Figure 1-3 Input warning display (A terminal) 23
Figure 1-4 Input warning display (µA mA terminal) 24
Figure 1-5 Unsecuring the instrument 38
Figure 1-6 Changing the calibration security code 39
Figure 1-7 Resetting the calibration security code 40
Figure 1-8 Reference value display 47
Figure 2-1 Testing Fuse 1 55
Figure 2-2 Testing Fuse 2 56
Figure 2-3 Replacing Fuse 1 58
Figure 2-4 Replacing Fuse 2 59
Figure 2-5 Positions of Fuse 1 and Fuse 2 60

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U1270 Series Service Guide XV
List of Tables
Ta b l e 1 - 1 Recommended test equipment 20
Ta b l e 1 - 2 Performance verification tests 28
Ta b l e 1 - 3 Adjustment input values 43
Ta b l e 1 - 4 Calibration error codes 50
Ta b l e 2 - 1 Operating checklist 52
Ta b l e 2 - 2 Fuse displayed readings 54

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17
U1270 Series Handheld Digital Multimeters
Service Guide
Agilent Technologies
1
Calibration Procedures
Calibration Overview 18
Closed-case calibration 18
Agilent calibration services 18
Calibration interval 19
Adjustment is recommended 19
Recommended Test Equipment 20
Basic Operating Test 22
Backlight test (U1271A/U1272A only) 22
Display test 22
Current terminal input test 23
Calibration Process 25
Test Considerations 26
Performance Verification Tests 27
Calibration Security 37
Unsecuring the Instrument for Calibration 38
To unsecure the instrument from the front panel 38
To change the calibration security code 39
To reset the calibration security code to its factory default 40
Using the Front Panel for Adjustments 42
Adjustment considerations 42
Valid adjustment input values 43
Adjustment procedure 47
Exiting the adjustment mode 48
Calibration Count 49
Calibration Error Codes 50
This chapter helps you to verify the instrument performance
and to make adjustments where necessary.

1 Calibration Procedures
Calibration Overview
18 U1270 Series Service Guide
Calibration Overview
This manual contains procedures to verify the U1270 Series
handheld digital multimeters performance and to perform
adjustments (calibration). The performance test procedures
allow you to verify that the instrument is operating within
its published specifications. The adjustment procedures
ensure that the instrument remains within its specifications
until the next calibration.
Closed-case calibration
The instrument features closed- case electronic calibration. In
other words, no internal mechanical adjustments are
required. The instrument calculates correction factors based
upon the input reference value you set. The new correction
factors are stored in the nonvolatile memory until the next
calibration adjustment is performed. The nonvolatile
EEPROM calibration memory is retained even when the
power is switched off.
Agilent calibration services
When your instrument is due for calibration, contact your
local Agilent Service Center to enquire about recalibration
services.
NOTE
Ensure that you have read the “Test Considerations” on page 26 before
calibrating the instrument.

Calibration Procedures 1
Calibration Overview
U1270 Series Service Guide 19
Calibration interval
A 1- year interval is adequate for most applications. Accuracy
specifications are warranted only if adjustment is made at
regular calibration intervals. Accuracy specifications are not
warranted beyond the 1- year calibration interval. Agilent
does not recommend extending calibration intervals beyond
2 years for any application.
Adjustment is recommended
Specifications are only guaranteed within the period stated
from the last adjustment. Agilent recommends that
re- adjustment should be performed during the calibration
process for best performance. This will ensure that the
instrument will remain within the specifications for the next
calibration interval.
This criterion for the re- adjustment provides the best
long- term stability. Performance data are measured during
the “Performance Verification Tests” but this does not
guarantee that the instrument will remain within these
limits unless the adjustments are performed.
Refer to the “Calibration Count” on page 49 and verify that
all the adjustments have been performed.

1 Calibration Procedures
Recommended Test Equipment
20 U1270 Series Service Guide
Recommended Test Equipment
The test equipment recommended for the performance
verification and adjustment procedures are listed below
(Table 1- 1). If the exact instrument is not available,
substitute with another calibration standard of equivalent
accuracy.
A suggested alternative method is to use the Agilent 3458A
8½ Digit Digital Multimeter to measure less accurate but
stable sources. The output value measured from the source
can be entered into the instrument as the target calibration
value.
Table 1-1 Recommended test equipment
Application Recommended
equipment Recommended accuracy requirements
DC voltage Fluke 5520A <20% of the U1270 Series accuracy
specification
DC current Fluke 5520A <20% of the U1270 Series accuracy
specification
Resistance Fluke 5520A <20% of the U1270 Series accuracy
specification
AC voltage Fluke 5520A <20% of the U1270 Series accuracy
specification
AC current Fluke 5520A <20% of the U1270 Series accuracy
specification
Frequency Fluke 5520A <20% of the U1270 Series accuracy
specification
Capacitance Fluke 5520A <20% of the U1270 Series accuracy
specification
Duty cycle Fluke 5520A <20% of the U1270 Series accuracy
specification
Diode Fluke 5520A <20% of the U1270 Series accuracy
specification