Keysight N1923/4A User manual

Keysight N1923/4A
Wideband Power Sensor
Service Guide

2 Keysight N1923/4A Service Guide
Notices
Copyright Notice
© Keysight Technologies 2011 - 2020
No part of this manual may be repro-
duced 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 Technol-
ogies as governed by United States and
international copyright laws.
Manual Part Number
N1923-90003
Edition
Edition 9, May 11, 2020
Printed in:
Printed in Malaysia
Published by:
Keysight Technologies
Bayan Lepas Free Industrial Zone,
11900 Penang, Malaysia
Technology Licenses
The hardware and/or software
described in this document are fur-
nished 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 prod-
ucts 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 Dec-
laration of Conformity.
U.S. Government Rights
The Software is “commercial computer
software,” as defined by Federal Acqui-
sition Regulation (“FAR”) 2.101. Pursu-
ant to FAR 12.212 and 27.405-3 and
Department of Defense FAR Supple-
ment (“DFARS”) 227.7202, the U.S.
government acquires commercial com-
puter 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 stan-
dard 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 Soft-
ware. The EULA and the license set
forth therein, does not require or per-
mit, among other things, that Keysight:
(1) Furnish technical information
related to commercial computer soft-
ware or commercial computer software
documentation that is not customarily
provided to the public; or (2) Relinquish
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explicitly required from all providers of
commercial computer software pursu-
ant to the FAR and the DFARS and are
set forth specifically in writing else-
where 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 DIS-
CLAIMS ALL WARRANTIES, EITHER
EXPRESS OR IMPLIED, WITH REGARD
TO THIS MANUAL AND ANY INFORMA-
TION CONTAINED HEREIN, INCLUD-
ING BUT NOT LIMITED TO THE
IMPLIED WARRANTIES OF MER-
CHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE. KEYSIGHT
SHALL NOT BE LIABLE FOR ERRORS
OR FOR INCIDENTAL OR CONSE-
QUENTIAL DAMAGES IN CONNECTION
WITH THE FURNISHING, USE, OR
PERFORMANCE OF THIS DOCUMENT
OR OF ANY INFORMATION CON-
TAINED HEREIN. SHOULD KEYSIGHT
AND THE USER HAVE A SEPARATE
WRITTEN AGREEMENT WITH WAR-
RANTY TERMS COVERING THE MATE-
RIAL IN THIS DOCUMENT THAT
CONFLICT WITH THESE TERMS, THE
WARRANTY TERMS IN THE SEPARATE
AGREEMENT SHALL CONTROL.
Safety Information
CAUTION
A CAUTION notice denotes a hazard. It
calls attention to an operating proce-
dure, 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 pro-
ceed 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 proce-
dure, 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.

Keysight N1923/4A Service Guide 3
Safety Considerations
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.
WARNING
Before connecting the sensor to other instruments, ensure that all
instruments are connected to the protective (earth) ground. Any interruption
of the protective earth grounding will cause a potential shock hazard that
could result in personal injury.
CAUTION
Repair or service that is not covered in this manual should only be performed
by qualified personnel.

4 Keysight N1923/4A Service Guide
Environmental Conditions
The N1923/4A is designed for indoor use and in an area with low condensation.
The table below shows the general environmental requirements for this
instrument.
Environmental condition Requirement
Temperature
Operating condition
– 0 °C to 55 °C
Storage condition
– –30 °C to 70 °C
Humidity
Operating condition
– Up to 95% RH at 40 °C (non-condensing)
Storage condition
– Up to 90% RH at 60 °C (non-condensing)
Altitude
Operating condition
– Up to 3,000 m (9,840 ft.)
Storage condition
– Up to 15,420 m (50,000 ft.)

Keysight N1923/4A Service Guide 5
Regulatory Information
The N1923/4A complies with the following Electromagnetic Compatibility (EMC)
compliances:
EMC compliance
– IEC 61326-1:2005/EN 61326-1:2006
– Canada: ICES/NMB-001:Issue 4, June 2006
– Australia/New Zealand: AS/NZS CISPR11:2004

6 Keysight N1923/4A Service Guide
Regulatory Markings
The RCM mark is a registered
trademark of the Australian
Communications and Media Authority.
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.
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.
ISM GRP.1 Class A indicates that this
is an Industrial Scientific and Medical
Group 1 Class A product.

Keysight N1923/4A Service Guide 7
Waste Electrical and Electronic Equipment (WEEE) Directive
This instrument complies with the WEEE Directive 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/xxxxx
(product-specific information and support, software and
documentation updates)
–www.keysight.com/find/assist
(worldwide contact information for repair and service)

8 Keysight N1923/4A Service Guide
In This Guide...
Chapter 1, "General Information"
Chapter 1 provides the specifications and maintenance information of the N1923/
4A.
Chapter 2, "Performance Tests and Adjustments"
Chapter 2 contains the performance test procedures which verify that the N1923/
4A is operating within its published specifications. This chapter also provides
information on adjustments performed after a performance test fails.
Chapter 3, "Theory of Operation"
Chapter 3 describes the operation and functions of the N1923/4A assembly.
Chapter 4, "Repair Guide"
Chapter 4 contains information on repair and replaceable parts of the N1923/4A.
This chapter also explains how to assemble and disassemble the N1923/4A.
Chapter 5, "Contacting Keysight"
Chapter 5 explains the appropriate actions to take if you have a problem with your
N1923/4A.

Keysight N1923/4A Service Guide 9
Table of Contents
Safety Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Environmental Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Regulatory Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
EMC compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Regulatory Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Waste Electrical and Electronic Equipment (WEEE) Directive . . . . . . . .7
Product category: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Sales and Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
In This Guide... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
1 General Information
Specifications and Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Connector care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
2 Performance Tests and Adjustments
Test Equipment List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Voltage Standing Wave Ratio (VSWR) Performance Test . . . . . . . . . . .21
Sensor Accuracy Performance Test . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
System-Level Rise and Fall Time Performance Test . . . . . . . . . . . . . . .26
Zero Set Performance Test in System Level . . . . . . . . . . . . . . . . . . . . .30
Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
3 Theory of Operation
Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
4RepairGuide
Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

10 Keysight N1923/4A Service Guide
Replaceable Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Disassembly/Reassembly Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Disassembly procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Reassembly procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
5ContactingKeysight
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Instrument serial numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Recommended calibration interval . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Returning the N1923/4A for Service . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Packaging the N1923/4A for shipment . . . . . . . . . . . . . . . . . . . . . . 46

Keysight N1923/4A Service Guide 11
List of Figures
Figure 2-1 Screenshot of the oscilloscope measurement display 27
Figure 3-1 Internal zeroing and calibration block diagram . . . . . .34
Figure 3-2 Measured rise time percentage error versus signal-un-
der-test rise time . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Figure 4-1 Removing the N1923/4A shell . . . . . . . . . . . . . . . . . . .40
Figure 5-1 Serial number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45

12 Keysight N1923/4A Service Guide
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Keysight N1923/4A Service Guide 13
List of Tables
Table 4-1 Replaceable parts list for the N1923/4A . . . . . . . . . . .39

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Keysight N1923/4A Wideband Power Sensor
Service Guide
15
1 General Information
Specifications and Characteristics 16
Cleaning 17
This chapter provides the specifications and maintenance information of the
N1923/4A wideband power sensor.

1 General Information
16 Keysight N1923/4A Service Guide
Specifications and Characteristics
For the N1923/4A specifications and characteristics, refer to the N1923/4A
datasheet at http://literature.cdn.keysight.com/litweb/pdf/5990-8126EN.pdf

General Information 1
Keysight N1923/4A Service Guide 17
Cleaning
Use a clean, water-dampened cloth to clean the body of the N1923/4A.
Connector care
A solution of pure isopropyl or ethyl alchohol can be used to clean the connector
but make sure to keep in mind on its flammable nature.
Clean the connector face by first using a blast of compressed air. If the
compressed air fails to remove contaminants, use a foam swab dipped in isopropyl
or ethyl alcohol. If the swab is too big, use a round wooden toothpick wrapped in a
lint-free cloth dipped in isopropyl or ethyl alcohol.
CAUTION
– The RF connector beads deteriorate when contacted by hydrocarbon
compounds such as acetone, trichloroethylene, carbon tetrachloride, and
benzene.
– Do not attempt to clean the connector with anything metallic such as pins
or
paper clips.
– Clean the connector only at a static free workstation. Electrostatic
discharge to the center pin of the connector will render the N1923/4A
inoperative.

1 General Information
18 Keysight N1923/4A Service Guide
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Keysight N1923/4A Wideband Power Sensor
Service Guide
19
2 Performance Tests and
Adjustments
Test Equipment List 20
Voltage Standing Wave Ratio (VSWR) Performance Test 21
Sensor Accuracy Performance Test 22
System-Level Rise and Fall Time Performance Test 26
Zero Set Performance Test in System Level 30
Adjustments 32
This chapter contains the performance test procedures which verify that the
N1923/4A is operating within its published specifications. This chapter also
provides information on adjustments performed after a performance test fails.

2 Performance Tests and Adjustments
20 Keysight N1923/4A Service Guide
Test Equipment List
The following equipment are required for the performance tests:
Equipment Critical specification Recommended Keysight model
number/part number
Signal generator Power range: –50 dBm to +22 dBm at 1 GHz
Output resistance: 50 ΩE8257D
Oscilloscope Analog bandwidth: 1 GHz and above Infiniium MSO 9104A
Network analyzer
Frequency range: 10 MHz to 40 GHz or above
Dynamic range: 94 dB
Trace noise: <0.006 dB
E8361A/E8361C/E8363B/E8363C
Peak power analyzer
Absolute accuracy: ±0.8%
Rise/fall time: <5 nsecs ± % error
Overshoot: 0.5%
8990B
Calibration kit Frequency range: DC to 18 GHz or above 85054A/85054D/85056A/85056D
Diode detector (negative) SMB connector 33334EZ
Power splitter Two-resistor type power splitter, N-type (f)
Maximum frequency: 18 GHz 11667A
Power meter
Dual-channel peak power meter, compatible with
P-Series and N8480 Series power sensors
Absolute accuracy: ±0.8%
N1912A
Power sensor
Frequency: 50 MHz or above
Power range: –30 dBm to +20 dBm
Standing wave ratio (SWR): ≤1.15 at 50 MHz
N8481A/N8487A
Wideband power sensor Power range: –30 dBm to +20 dBm
SWR: ≤1.20 at 1 GHz N1921A/N1922A
Cable adapter 11730A sensor cable adapter N1911A-200
N-type-to-SMA adapter N-type (m) to 2.4 mm SMA (f) 11903D
Trigger cable BNC (m) to SMB (f)
Characteristic impedance: 50 ΩU2032A