Keysight 85024A High
Frequency Probe
User’s and
Service Guide
Notices
CAUTION
WARNING
Copyright Notice
© Keysight Technologies 2014 - 2018
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 Technologies as governed by United States and
international copyright laws.
Manual Part Number
85024-90031
Edition
Edition 2, September 24, 2018
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 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 85024A User’s and Service Guide
Warranty
Limitation of warranty
Exclusive remedies
This product is warranted against defects in material and workmanship for a
period of one year from date of shipment. During the warranty period, Keysight
Technologies will, at its option, either repair or replace products which prove to be
defective.
For warranty service or repair, this product must be returned to a service facility
designated by Keysight. Buyer shall prepay shipping charges to Keysight and
Keysight shall pay shipping charges to return the product to Buyer. However,
Buyer shall pay all shipping charges, duties, and taxes for products returned to
Keysight from another country.
The foregoing warranty shall not apply to defects resulting from improper or
inadequate maintenance by Buyer, Buyer-supplied software or interfacing,
unauthorized modification or misuse, operation outside of the environmental
specifications for the product, or improper site preparation or maintenance.
NO OTHER WARRANTY IS EXPRESSED OR IMPLIED. KEYSIGHT TECHNOLOGIES
SPECIFICALLY DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS FOR A PARTICULAR PURPOSE.
THE REMEDIES PROVIDED HEREIN ARE BUYER’S SOLE AND EXCLUSIVE
REMEDIES. KEYSIGHT TECHNOLOGIES SHALL NOT BE LIABLE FOR ANY DIRECT,
INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WHETHER
BASED ON CONTRACT, TORT, OR ANY OTHER LEGAL THEORY.
Keysight 85024A User’s and Service Guide 3
Assistance
Product maintenance agreements and other customer assistance agreements are
available for Keysight products.
For any assistance, contact the nearest Keysight sales or service office. Refer to
“Sales and Technical Support” on page 6 for a list of Keysight offices.
How to Use This Guide
This guide uses the following conventions:
[Front Panel Key] This represents a key physically located on the
SOFTKEY This represents a “softkey”, a key whose label is
Environmental Conditions
The 85024A is designed for indoor use and in an area with low condensation. The
table below shows the general environmental requirements for this instrument.
instrument.
determined by the instrument firmware.
Environmental condition Requirement
Operating condition
Temperature
Humidity
Altitude
4 Keysight 85024A User’s and Service Guide
– 0 °C to 55 °C
Storage condition
– –40 °C to 70 °C
Protect this product from temperature extremes which can
cause internal condensation.
Operating condition
– Up to 4,600 meters (15,000 feet)
Storage condition
– Up to 15,000 meters (50,000 feet)
Regulatory Markings
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.
This symbol is a South Korean Class A EMC Declaration. This is a Class A instrument suitable for
professional use and in electromagnetic environment outside of the home.
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.
Keysight 85024A User’s and Service Guide 5
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/rfprobes
(product-specific information and support, software and
documentation updates)
– www.keysight.com/find/assist
(worldwide contact information for repair and service)
6 Keysight 85024A User’s and Service Guide
Table of Contents
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Limitation of warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Exclusive remedies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
How to Use This Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Environmental Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Regulatory Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Waste Electrical and Electronic Equipment (WEEE) Directive . . . . . . . .6
Product category: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Sales and Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1 General Information
Read This Before Using Your Probe . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Maximum rated input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Anti-Static Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Product Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Specifications and Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
2 Accessories
Probe Features and Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Probe Adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Operating characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
10:1 Divider . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Operating characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Replaceable parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Keysight 85024A User’s and Service Guide 7
3Installation
Initial Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Preparation for Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Power requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Mating Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Returning the Product for Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
4Operation
Operating Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Grounding the probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Retracting and extending the protective sleeve . . . . . . . . . . . . . . . . 33
Operator’s Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Operator’s check using a network analyzer . . . . . . . . . . . . . . . . . . . 34
Operator’s check using a spectrum analyzer . . . . . . . . . . . . . . . . . . 35
5 Performance Tests
Recommended Test Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Network Analyzer Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Median Gain and Frequency Response Flatness . . . . . . . . . . . . . . . . . . 41
Gain Compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Average Noise Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Test Record . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
6Replaceable Parts
Introduction and Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . 50
Parts Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
8 Keysight 85024A User’s and Service Guide
7Service
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
Before you troubleshoot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
Equipment required for troubleshooting . . . . . . . . . . . . . . . . . . . . . .56
Repair strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58
ESD protection at the probe tip . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
Troubleshooting Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
Mechanical failure of the protective sleeve . . . . . . . . . . . . . . . . . . . .60
Electrical failure of the probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65
Replacing the probe tip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Replacing the amplifier microcircuit . . . . . . . . . . . . . . . . . . . . . . . . .66
Removing the plastic regulator housing covers . . . . . . . . . . . . . . . .67
Replacing the type-N output connector . . . . . . . . . . . . . . . . . . . . . .69
Cable/Probe wand replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . .70
Connector Inspection and Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Inspecting the connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74
Visual examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74
Cleaning connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
Keysight 85024A User’s and Service Guide 9
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10 Keysight 85024A User’s and Service Guide
List of Figures
Figure 1-1 Probe with 10:1 divider and anti-static protection
Figure 2-1 Probe features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Figure 2-2 Exploded view of 10:1 divider . . . . . . . . . . . . . . . . . . . 26
Figure 6-1 Replaceable parts identification . . . . . . . . . . . . . . . . .53
Figure 7-1 Probe tip input circuit . . . . . . . . . . . . . . . . . . . . . . . . . .59
Figure 7-2 A1 regulator schematic diagram and overall block
Figure 7-3 High frequency probe . . . . . . . . . . . . . . . . . . . . . . . . . 62
Figure 7-4 Power supply check points . . . . . . . . . . . . . . . . . . . . .63
Figure 7-5 A1 regulator assembly 85024-6307 . . . . . . . . . . . . . .64
Figure 7-6 Probe end disassembly . . . . . . . . . . . . . . . . . . . . . . . .66
Figure 7-7 Probe wand components . . . . . . . . . . . . . . . . . . . . . . .67
Figure 7-8 Cover removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Figure 7-9 Output connector parts . . . . . . . . . . . . . . . . . . . . . . . .69
Figure 7-10 Special spanner/wrench tool and area of use . . . . . . .72
Figure 7-11 Regulator parts and wiring . . . . . . . . . . . . . . . . . . . . .73
cap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
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12 Keysight 85024A User’s and Service Guide
List of Tables
Table 2-1 Probe features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Table 2-2 Available accessories . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Table 5-1 Recommended test equipment . . . . . . . . . . . . . . . . . . 38
Table 6-1 Miscellaneous replacement parts . . . . . . . . . . . . . . . .51
Table 6-2 Replaceable parts . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
Keysight 85024A User’s and Service Guide 13
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14 Keysight 85024A User’s and Service Guide
Keysight 85024A High Frequency Probe
User’s and Service Guide
1 General Information
Read This Before Using Your Probe 16
Anti-Static Precautions 17
Product Description 18
Specifications and Characteristics 19
15
1 General Information
Read This Before Using Your Probe
Your probe has been designed to provide years of uninterrupted service. Excellent
performance at high frequencies requires the use of very small and delicate
devices. Such components can be damaged by careless use.
Maximum rated input voltage
It is vital that the following specifications are not exceeded:
– Maximum DC input voltage (without 10:1 divider): ±50 V
– Maximum DC input voltage through a 10:1 divider: ±50 V
– Maximum RF voltage (without 10:1 divider): 1.5 V peak
– Maximum RF voltage through a 10:1 divider: 15 V peak
To minimize the potential for damage, always begin measurements with the 10:1
divider attached.
Remove the 10:1 divider only when both of the following conditions are met:
– RF and DC levels are known to be less than or equal to the rated input voltage.
– Higher sensitivity is required than is possible with the 10:1 divider attached.
When the probe is stored, attach the 10:1 divider and place the anti-static
protection cap over the probe tip.
Figure 1-1 Probe with 10:1 divider and anti-static protection cap
16 Keysight 85024A User’s and Service Guide
Anti-Static Precautions
Electrostatic discharge (ESD) is a serious problem; take consistent steps to
eliminate it. This is important whenever using your probe.
– Never touch the tip of the probe. The probe microcircuit is susceptible to
damage by static discharge.
– Eliminate ESD on the body. Wear a ground strap when using the probe.
– Eliminate ESD on the work surface. Use an anti-static bench mat. Never use
the probe near a workbench that is covered by carpet.
Do not introduce ESD into the device under test (DUT) while the probe is in use. If
an unprotected person touches part of the DUT, a static charge could damage the
DUT as well as the probe.
General Information 1
Keysight 85024A User’s and Service Guide 17
1 General Information
Product Description
Your high frequency probe is an active probe that provides low input capacitance,
high input impedance, and wide bandwidth. The probe may be used with a variety
of network analyzers, spectrum analyzers, frequency counters, and oscilloscopes.
The probe allows the testing of high frequency RF circuits. High input impedance
is maintained by a Gallium Arsenide (GaAs) field effect transistor (FET)
microcircuit.
When not in use, the probe tip is protected by a retractable grounded metal
sleeve. This helps prevent electrostatic discharge damage to the probe, and
protects the tip from breaking if the probe is dropped.
The probe tip may be inserted into the supplied probe adapter, adjusting the
probe tip to a 50 W type-N male connector. The probe’s output connector is a
type-N male.
18 Keysight 85024A User’s and Service Guide
Specifications and Characteristics
For the specifications and characteristics of the 85024A High Frequency Probe,
refer to the data sheet at http://literature.cdn.keysight.com/litweb/pdf/
5968-2101E.pdf
General Information 1
Keysight 85024A User’s and Service Guide 19
1 General Information
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20 Keysight 85024A User’s and Service Guide
Keysight 85024A High Frequency Probe
User’s and Service Guide
2 Accessories
Probe Features and Accessories 22
Probe Adapter 24
10:1 Divider 25
21
2 Accessories
Probe Features and Accessories
Figure 2-1 Probe features
22 Keysight 85024A User’s and Service Guide
Table 2-1 Probe features
Item Description Keysight part number
1 Probe tip 85024-60015
2, 3 Cable/Probe wand kit (pre-assembled) 85024-60014
4 Regulator assembly (internal PC board) 85024-63071
5 RF output connector (type-N male) 85024-60013
6 Probe tip to type-N adapter 11880-60001
7 10:1 divider 11881-60001
8 Probe tip nut driver 8710-1806
9 Ground lead, flexible 41800-61672
10 Slip-on tip with grounding spike 5060-0549
Replacement tip (short)
11
Replacement tip (long)
12 Hook tip adapter 10229A
13 Anti-static protection cap 08405-40003
85024-60015
85024-60016
Accessories 2
Table 2-2 Available accessories
Description Keysight part or model number
Type-N connector gage kit 85054B
Adapter, type-N female to precision 7 mm
Adapter, type-N female to BNC male
External DC power supply adapter cable
[a] Used with the 85046A s-parameter test set.
[b] Used with the 8590A spectrum analyzer.
[c] Requires the E3620A, E3630A, or E3631A External Power Supply from Keysight Technologies.
[a]
[b]
[c]
11524A
1250-1477
85024A-001
Keysight 85024A User’s and Service Guide 23
2 Accessories
Probe Adapter
Description
The probe adapter fits over the tip of the probe and converts the probe input to a
50 W type-N male connector. The adapter is only used when performance testing
the probe.
Operating characteristics
Nominal input impedance 50 W
Frequency range Same as the active probe (300 kHz to 3 GHz)
Inspection
Periodically inspect the threads of the adapter for signs of wear and damage.
Inspect the barrel of the probe receptacle, making sure it is clean and free of grit.
Clean the adapter threads or receptacle with clean compressed air.
24 Keysight 85024A User’s and Service Guide
10:1 Divider
Operating characteristics
Accessories 2
The 10:1 divider fits over the tip of the probe and provides the following changes
to the probe’s operating parameters:
– Increases (by a factor of 10) the input voltage at which 1 dB compression
occurs.
– Decreases the input capacitance without changing input resistance, thereby
decreasing capacitive loading.
Two or more dividers may be cascaded to provide higher divide ratios.
Divider ratio 10:1
Input capacitance Typically <0.7 pF
Input resistance 1 MW
Input voltage for 1 dB compression
Maximum rated DC input voltage ±50 volts
Maximum rated RF input voltage 15 volts peak
Frequency range Same as the active probe (300 kHz to 3 GHz)
3.0 volts peak
[a]
[a] When used with the active probe.
Inspection
Make sure the tip is not bent or discolored. Periodically inspect the barrel of the
probe receptacle, making sure it is clean and free of grit. Clean the receptacle with
clean compressed air.
When cascading 10:1 dividers, periodically inspect and clean the exterior of the
metal sleeve.
Keysight 85024A User’s and Service Guide 25
2 Accessories
Replaceable parts
If the tip is discolored, bent or broken, it must be replaced. Follow the procedure
outlined in Replacing the probe tip below.
Item Description Part number
1 Short probe tip
Long probe tip
2 Guide 11881-20007
85024-60015
85024-60016
Figure 2-2 Exploded view of 10:1 divider
Replacing the probe tip
1 Remove the 10:1 divider from the probe.
2 Unscrew the damaged tip with a 3/32 nut driver supplied with the probe and
discard the tip.
3 Screw on the new tip and lightly tighten it with a 3/32 inch nut driver.
(Over-tightening the tip can damage the nose assembly.)
26 Keysight 85024A User’s and Service Guide
Keysight 85024A High Frequency Probe
User’s and Service Guide
3 Installation
Initial Inspection 28
Certification 28
Preparation for Use 29
Mating Connectors 30
Returning the Product for Service 30
27
3Installation
Initial Inspection
If the shipping container or cushioning material is damaged, keep it until the
contents of the shipment are checked for completeness, and the product is
checked both mechanically and electrically. Procedures for checking the electrical
performance are given in Chapter 5, "Performance Tests".
Notify the nearest Keysight Technologies office if the product does not pass
performance tests, the shipping contents are incomplete, or if there is mechanical
damage or defect. Notify the carrier if the shipping container is damaged or if the
cushioning material shows signs of stress. Keep all shipping materials for the
carrier’s inspection. Keysight Technologies will arrange for repair or replacement
without waiting for a claim settlement.
Certification
Keysight Technologies certifies that this product met its published specifications
at the time of shipment from the factory. Keysight further certifies that its
calibration measurements are traceable to the United States National Institute of
Standards and Technology (NIST, formerly NBC), to the extent allowed by the
institute’s calibration facility, and to the calibration facilities of other International
Standards Organization members.
28 Keysight 85024A User’s and Service Guide
Preparation for Use
CAUTION
Electrostatic discharge (ESD), excessive input signals, or mechanical shock
can dramatically degrade the performance of the probe. Be sure to observe
the following precautions.
– Never touch the tip of the probe!
– Always hold the probe by the retracted metal sleeve.
– Work at a workstation equipped with an anti-static mat.
– Extend the protective sleeve when not actually taking measurements.
– Wear an anti-static wrist strap and avoid introducing static electricity into
the device under test (DUT) or test setup.
– Make sure the device under test (DUT) is at the same ground potential as
the probe.
Power requirements
If using the probe with an instrument that does not supply probe power, you can
purchase an 85024A-001 adapter cable assembly and one of the following
Keysight external power supplies:
– E3620A
Installation 3
– E3630A
– E3631A
You need to ensure the correct setting of the power supply (+15 V and –12.6 V)
per attached labels on the 85024A-001 adapter cable assembly.
Keysight 85024A User’s and Service Guide 29
3Installation
CAUTION
Mating Connectors
Periodically inspect and, if necessary, clean the type-N output connector.
Refer to “Connector Inspection and Cleaning” on page 74. The probe adapter
should be inspected at the same time, and cleaned if necessary.
Returning the Product for Service
Contact Keysight Technologies before returning the probe for service. See “Sales
and Technical Support” on page 6. When shipping the probe to Keysight
Technologies please include a blue service tag (found at the end of this manual)
and a valid return mailing address. Products cannot be returned to a post office
box. Provide the name and phone number of a contact person within your
organization, the complete model and serial number of the product, and a
complete description of the problem.
When shipping the probe for any reason, be sure to use the original (or
comparable) packaging materials.
Also mark the container FRAGILE to assure careful handling of the device.
When making inquiries, either by correspondence or by telephone, please refer to
the probe by model and full serial number. Refer to “Sales and Technical Support”
on page 6 for a list of Keysight Technologies sales and service offices.
30 Keysight 85024A User’s and Service Guide
Keysight 85024A High Frequency Probe
User’s and Service Guide
4 Operation
Operating Precautions 32
Operating Instructions 33
Operator’s Check 34
31
4Operation
CAUTION
Operating Precautions
Electrostatic discharge (ESD), excessive input signals or mechanical shock
can dramatically degrade the performance of the probe. Be sure to observe
the following precautions.
– Never touch the tip of the probe!
– Always hold the probe by the retracted metal sleeve.
– Work at a workstation equipped with an anti-static mat.
– Extend the protective sleeve when not actually taking measurements.
– Wear an anti-static wrist strap and avoid introducing static electricity into
the device under test (DUT) or test setup.
– Make sure the device under test (DUT) is at the same ground potential as
the probe.
32 Keysight 85024A User’s and Service Guide
Operating Instructions
CAUTION
Discharging the Probe Between Measurements
Measuring a node having a DC voltage potential charges blocking capacitors
inside of the probe. Ground the probe tip after measuring such nodes to
discharge the probe capacitors.
Failure to do this can result in damage to sensitive circuits in the DUT,
especially if it is an active device.
Grounding the probe
Proper grounding is important when making measurements with any probe. The
probe is supplied with two grounding devices: an alligator-type ground clip and a
slip-on type ground tip. Use the shortest ground path possible. Proper grounding
becomes more important as frequency increases. For optimum measurements in a
factory environment, design your circuits with ground-plane feedthroughs next to
every test point.
Operation 4
Retracting and extending the protective sleeve
Hold the probe wand in one hand, pointing the tip away from yourself. Grasp the
probe sleeve in the other hand and turn about 1/4 turn counter-clockwise. Now,
pull the sleeve toward you while slowly turning it counter-clockwise. The sleeve
will now retract quickly with little counter-clockwise rotation. Reverse this
procedure to extend the sleeve.
Keysight 85024A User’s and Service Guide 33
4Operation
NOTE
Operator’s Check
The operator’s check is designed to be a simple functional test for the probe. If the
probe fails the operator’s check, or if you need to verify that the probe meets its
warranted specifications, you will need to do the performance tests as described
in Chapter 5, "Performance Tests".
The operator’s check can be performed with either a network analyzer or a
spectrum analyzer. Use one of the following two procedures to perform the
operator’s check.
Operator’s check using a network analyzer
Required equipment
Item Part number
Network analyzer Any compatible with type-N connectors
Type-N cable 50 W, male connectors
Probe adapter 11880-60001
Procedure
If you are not familiar with network analyzer operation, refer to “Network
Analyzer Operation” on page 39 for basic information about performing the
analyzer operations used in this procedure.
1 Preset the analyzer using the [PRESET] hardkey.
2 Configure the analyzer to measure transmission.
3 Set the output power level of the analyzer to 0 dBm.
4 Set the frequency sweep range on the analyzer from 300 kHz to 3 GHz.
5 Connect a type-N cable (a through cable) between the output and the input
ports on the analyzer.
6 Perform a response calibration on the analyzer. The trace on the analyzer
should now be flat at 0 dB.
34 Keysight 85024A User’s and Service Guide
7 Remove the through cable. Connect the probe adapter to the output port of
the analyzer. Connect the output of the probe to the input port of the analyzer.
Connect the probe power cable to a power source.
8 Plug the probe tip into the adapter.
9 The trace of the analyzer should be within ±5 dB of 0 dB.
Operator’s check using a spectrum analyzer
Required equipment
Item Part number
Spectrum analyzer Any compatible
Adapters As necessary
Probe adapters 11880-60001
Procedure
1 Connect the spectrum analyzer’s calibration output directly to its RF input.
Turn on the spectrum analyzer.
2 Set the spectrum analyzer center frequency to the frequency of the calibration
output.
3 Set the frequency span to 10 MHz and activate a marker.
Operation 4
4 Place the marker on the peak of the displayed signal and note the value in
dBm.
5 Connect the probe adapter to the calibration output.
6 Connect the probe output to the RF input on the analyzer.
7 Connect the probe power cable to a power source.
8 Plug the probe tip into the probe adapter.
9 Place the marker on the peak of the displayed signal and compare the signal
level in dBm to that measured in step 4. The probe should not cause more than
5 dBm of signal loss.
Keysight 85024A User’s and Service Guide 35
4Operation
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36 Keysight 85024A User’s and Service Guide
Keysight 85024A High Frequency Probe
NOTE
User’s and Service Guide
5 Performance Tests
Recommended Test Equipment 38
Network Analyzer Operation 39
Median Gain and Frequency Response Flatness 41
Gain Compression 43
Average Noise Level 46
Test Record 47
The procedures in this chapter test the probe to ensure that it meets the
warranted specifications listed in the data sheet (see “Specifications and
Characteristics” on page 19). The “Test Record” on page 47 provides space to
record the test results. Each of the tests can be performed without access to the
interior of the probe. Follow the procedures, record data on the ““Test Record” on
page 47, perform the calculations, and determine pass or fail for each test item.
All tests must pass for the performance test to be verified.
The performance tests in this chapter cover the specifications for a standard
85024A probe. If the serial number label indicates an option, contact Keysight
Technologies for applicable specifications. Refer to “Sales and Technical
Support” on page 6 for a list of Keysight Technologies sales and service offices.
37
5 Performance Tests
Recommended Test Equipment
Table 5-1 lists the equipment that is recommended for use in performance testing
of the probe. Other equipment may be substituted if its specifications meet or
exceed the specifications listed in the “Critical Specifications” column.
Tab le 5-1 Recommended test equipment
Type Critical specifications
Vector network analyzer 300 kHz to 3 GHz
Power meter 437B/438A or E4418A/E4419A
Power sensor
Type-N cable, male-to-male 50 W 8120-8862 or equivalent
Probe adapter Supplied with probe 11880-60001
Attenuator, type-N, 50 W Any value 10 to 20 dB nominal
Type-N Adapter,
female-to-female
[a] Many models of network analyzers can be used for these performance tests. The network analyzer must cover the
frequency range 300 kHz to 3 GHz, and be capable of power output in the range of –3 to +5 dBm.
300 kHz to 3 GHz
–30 dBm to +5 dBm
Recommended
model or part number
8714ET/ES, 8753ET/ES, 8753E
8482A
8491A/B/C Option 20, Option 10,
or equivalent
1250-0777 or equivalent
[a]
38 Keysight 85024A User’s and Service Guide
Network Analyzer Operation
This section provides some general information for performing basic network
analyzer operations. For more specific operating information, refer to your
analyzers user’s guide.
Presetting the network analyzer
All analyzers have a [PRESET] hardkey for this function.
Selecting a transmission (or S21 measurement)
871x family Press [MEAS 1], then Transmission or Fwd Trans S21.
Performance Tests 5
8753 family
Press [Chan 1] or [CH 1], then [Meas] followed by
Transmission or TRANS:FWD.
Setting the frequency range
871x family Start and stop frequencies are accessed via [FREQ].
8753 family
Start and stop frequencies are accessed via [Start] and
[Stop].
Setting CW mode for power meter measurements
Press [FREQ] CW, then [MENU] and set the Trigger mode to
871x family
8753 family
Hold. To return to normal operation, set the trigger mode to
Continuous and define start and stop frequencies.
Press [Menu] or [Sweep Setup] to access both the sweep and
trigger functions. The CW FREQ softkey activates CW mode,
press TRIGGER MENU then HOLD. To return to normal
operation, change the trigger mode to CONTINUOUS, [Menu]
or [Sweep Setup], then SWEEP TYPE MENU followed by
LIN FREQ.
Keysight 85024A User’s and Service Guide 39
5 Performance Tests
Setting the output power level
871x family Press [POWER].
8753 family
Press [Menu] or [Sweep Setup] to access Power.
Performing a response calibration
871xC and
871xET
871xES
8753 family
Press [CAL], then Response.
Press Measure Standard when the through cable is
connected.
Press [CAL], User Response, then Response.
Press Measure Standard when the through cable is
connected.
Press [Cal], CALIBRATE MENU, then Response.
Press THRU when the through cable is connected.
40 Keysight 85024A User’s and Service Guide
Median Gain and Frequency Response Flatness
Specifications (at 25 °C ±5 °C)
Median gain over 300 kHz to 1 GHz 0 dB ±1.25 dB
Frequency response flatness (relative to med ian gain)
300 kHz to 1 GHz ±1.25 dB
1 GHz to 3 GHz ±2.5 dB
Description
This test procedure performs a response calibration on the analyzer and then
measures the gain of the probe over frequency. Maximum and minimum gains in
two different frequency bands are used to determine the probe performance.
Procedure
1 Preset the analyzer using the [PRESET] hardkey.
2 Set the frequency sweep range for 300 kHz to 3 GHz.
3 Set the analyzer for a transmission (S21) measurement.
4 Connect a type-N cable between the output port and input port on the
analyzer.
Performance Tests 5
5 Perform a response calibration on the analyzer. The trace on the analyzer
should now be a flat line at 0 dB.
6 Disconnect the cable from the output port of the analyzer. Connect the type-N
barrel to the free end of the cable.
7 Connect the probe adapter to the output port of the analyzer. Connect the
probe between the probe adapter and the type-N barrel. Plug the probe power
cable into the front panel of the analyzer.
Keysight 85024A User’s and Service Guide 41
5 Performance Tests
8 Read the following four values from the trace on the analyzer and enter the
values on the “Test Record” on page 47. Use the network analyzer marker
functions as needed.
Perform the calculations indicated on the test record to determine the results
of the test.
Maximum gain in dB over the frequency range of 300 kHz to 1 GHz (A).
Minimum gain in dB over the frequency range of 300 kHz to 1 GHz (B).
Maximum gain in dB over the frequency range of 1 GHz to 3 GHz (C).
Minimum gain in dB over the frequency range of 1 GHz to 3 GHz (D).
42 Keysight 85024A User’s and Service Guide
Gain Compression
Specifications (at 25 °C ±5 °C) <1.0 dB at 0.3 V Peak
In a 50 W system 0.3 V Peak = –0.458 dBm
Description
This test identifies the frequency of greatest compression at a signal level of 0.3 V
peak (–0.458 dBm). It then uses a power meter to precisely measure the
compression at that frequency.
Procedure
1 Select an attenuator to use: its nominal value must be in the 10 to 20 dB
range.
2 Plug the power sensor into the power meter and turn on the power meter.
Allow them to warm up for 3 minutes.
3 Calibrate and zero the power meter and the power sensor.
4 Preset the analyzer using the [PRESET] hardkey.
Performance Tests 5
5 Set up the analyzer to measure transmission (S21) over the 300 kHz to 3 GHz
range.
6 Set the power level on the analyzer to 0 dBm.
7 Connect the probe adapter to the output of the analyzer.
8 Connect the output of the probe to the input port of the analyzer. Plug the
probe tip into the adapter. Connect the probe power cable to a power source.
9 Perform a response calibration on the analyzer using the probe as the “through
cable.” The trace on the analyzer should now be a flat line at 0 dB.
10 Insert the attenuator between the output port of the analyzer and the probe
adapter. Reconnect the probe to the probe adapter.
11 Determine the frequency of peak gain on the trace of the analyzer. Record the
frequency on the test record.
12 Set the analyzer to CW mode for power meter measurements. Set the CW
frequency to the value determined in the previous step.
13 Remove the attenuator from the output port of the analyzer.
Keysight 85024A User’s and Service Guide 43
5 Performance Tests
NOTE
14 Connect the power sensor to the output port of the analyzer. Adjust the
analyzer power output level to produce a reading of 0.0 dBm on the power
meter.
0.0 dBm is used to allow for possible inaccuracy of power meters
15 Disconnect the power sensor from the output port of the analyzer. Connect the
attenuator to the output port of the analyzer.
16 Connect the probe, the probe adapter, and a barrel between the attenuator
and the power sensor. The signal from the analyzer should now go through the
attenuator and then the probe before reaching the power sensor. Record the
power reading on the “Test Record” on page 47 (item F).
17 Remove the attenuator pad, connect the probe adapter to the output port of
the analyzer. Connect the attenuator pad between the probe and the power
sensor. The signal from the analyzer should now go through the probe and
then the pad before reaching the power sensor. Record the power reading on
the “Test Record” on page 47 (item G).
18 Perform the calculation indicated on the test record to determine the result of
the test.
44 Keysight 85024A User’s and Service Guide
Performance Tests 5
V
pk
1.4142135
---------------------
0.3V
1.4142135
--------------------- 0.212132V
RMS
=
V
2
R
----
0.212132()
2
50W
-------------------------0.0009w=
0.009w
0.001w
-------------- 0.9=
Calculating equivalent power
The probe is usually used as a high impedance device. The compression
specification is given as a voltage (instead of power) because of the wide range of
devices with which the probe may be used. For testing the probe, the probe
adapter is used to make the probe input 50 W. Using this known impedance, an
equivalent power can be calculated.
To find the power level equivalent to the 0.3 peak voltage, perform the following
mathematical steps:
Steps Formula Example
1 Convert the peak voltage into
RMS.?
2 Convert the RMS voltage to a
raw power.
3 Convert the raw power to a
power which is relative to
1 mW.
4 Convert to dBm. 10(LOGx)
Divide by 0.001w
10(LOG 0.9) = –0.458 dBm
[a]
Keysight 85024A User’s and Service Guide 45
[a] Therefore, as shown in the example, the equivalent power to 0.3 V peak in a 50 W system is –0.458 dBm.
5 Performance Tests
Average Noise Level
Specifications (at 25 °C ±5 °C) <17 mV RTI (or –23 dBm at probe output)
Description
This test procedure uses a power meter to measure the power level of the probe
output when the probe tip is connected through 50 ohms to ground.
Procedure
1 Connect the power sensor to the power meter and allow the power meter to
warm up for five minutes.
2 Calibrate and zero the power meter.
3 Enable averaging on the power meter.
4 Connect the power cable on the RF probe to a power source, allow the probe
to warm up for at least three minutes.
5 Connect the probe tip adapter to the tip of the probe. (This effectively grounds
the probe tip).
6 Connect the RF probe to the power sensor using a type-N barrel.
7 Read the power meter. If the reading is unstable, visually determine the
approximate peak value over a period of about twenty seconds. Record that
value on the test record.
46 Keysight 85024A User’s and Service Guide
Performance Tests 5
Test Record
85024A High Frequency Probe Test Record
Serial number: Date:
Tested by: Temperature:
Median gain and frequency response flatness
A Maximum gain over 300 kHz to 1 GHz dB N/A N/A N/A
B Minimum gain over 300 kHz to 1 GHz dB N/A N/A N/A
C Maximum gain over 1 GHz to 3 GHz dB N/A N/A N/A
D Minimum gain over 1 GHz to 3 GHz dB N/A N/A N/A
E Median gain (A+B)/2 = dB 1.25 –1.25
LF maximum gain A – E = dB 1.25 0
LF minimum gain B – E = dB 0 –1.25
HF maximum gain C – E = dB 2.5 –2.5
HF minimum gain D – E = dB 2.5 –2.5
Results
[a]
Limits
Max Min
Pass/
Fail
Gain compression
Frequency at maximum gain N/A N/A N/A
F Pad before probe dBm N/A N/A N/A
G Pad after probe dBm N/A N/A N/A
Compression, D – E = dBm +1.0 N/A
Average noise level
dBm –23 N/A
[a] Reminder: Include polarity (+/–) in all recorded values and calculations.
Keysight 85024A User’s and Service Guide 47
5 Performance Tests
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48 Keysight 85024A User’s and Service Guide
Keysight 85024A High Frequency Probe
User’s and Service Guide
6 Replaceable Parts
Introduction and Ordering Information 50
Parts Lists 51
49
6 Replaceable Parts
NOTE
Introduction and Ordering Information
The replaceable parts lists are organized as follows:
Table 6-2 contains components and assemblies of the high frequency probe given
in alphabetic/numerical order by reference designation.
The total quantity for each part is given only once, at the first appearance of the
part in the list.
To order a part listed in the replaceable parts list, indicate the Keysight part
number and the quantity desired. Address the order to the nearest Keysight
Technologies office.
To order a part that is not listed in the replaceable parts list, include the probe
model and serial number, the description and function of the part and the
quantity desired. Address the order to the nearest Keysight Technologies office.
See “Sales and Technical Support” on page 6 for a list of Keysight Technologies
sales and service offices.
50 Keysight 85024A User’s and Service Guide
Parts Lists
Table 6-1 Miscellaneous replacement parts
Part number Qty Description
08405-40003 1
Anti-static protection cap
1401-0214 1 Protective end cap for type-N connector
85024-90031 1 Operating and service manual
85024-80001 2 Side label
85024-80003 1 Product case
85024-80004 1 Bottom foam of the product case
5180-8448 1 Top foam of the product case
41800-61672 1
5060-0549 1
10229A 1
8710-1806 1
11880-60001 1
Ground lead, flexible
Ground tip, slip-on with grounding spike
Hook tip adapter
3/32 inch probe tip nut driver
Type-N probe adapter
11881-60001 1 10:1 divider
Service tool
[a]
[a]
[a]
[a]
[a]
Replaceable Parts 6
[a]
85024-20041 Spanner/Wrench (see Figure 7-10)
General accessories
1250-1477
[a] Shown in Figure 2-1.
[b] For use with the 8590A spectrum analyzer.
Adapter, type-N female to BNC male
[b]
Keysight 85024A User’s and Service Guide 51
6 Replaceable Parts
Tab le 6-2 Replaceable parts
[a]
Item
Part number Qty Description
1 85024-60013 Connector replacement kit
2 85024-20024 1 RF bead
3 85024-20016 1 Transition-nut
4 85024-20017 1 Transition-REG
5 0515-0912 2 Screw-machined M3 x 0.5 8 mm-LG pan head
6 85024-20028 1 Frame casting
7 85024-20025 1 Nut, strain relief
8 85024-60014 Cable/Probe wand kit (pre-assembled)
9 0515-0659 2 Screw-machined M2 8 mm-LG pan head
10 0515-0658 2 Screw-machined M2 6 mm-LG pan head
11 85024-20015 1 Probe nut
12 85024-60015 1 Short power tip (also used on 10:1 divider)
85024-60016 1 Long power tip
13 85024-60011 1 Nose assembly
14 85024-40007 1 Conductive washer
15 85024-60005 1 Amplifier microcircuit
16 85024-20037 1 Clip spring for elastic conductive strip
17 85024-20035 1 Elastic conductive strip
18 85025-40006 1 Regulator assembly plastic cover
A1 85024-63071 1 Regulator assembly (internal PC board)
19 85024-00002 1 Housing reinforcement
20 5040-0494 1 Connector sleeve (power)
21 5060-0466 1 Connector body (power)
[a] See Figure 6-1, “Replaceable parts identification” on page 53.
52 Keysight 85024A User’s and Service Guide
Replaceable Parts 6
CAUTION
NOTE
Figure 6-1 Replaceable parts identification
Failure to remove the nose assembly prior to replacing the tip will result in
damage to the conductive elastometer on the tip assembly.
Item 11 is a nut which slides over items 12 through 17 and screws onto the end
of the heat sink.
Keysight 85024A User’s and Service Guide 53
6 Replaceable Parts
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54 Keysight 85024A User’s and Service Guide
Keysight 85024A High Frequency Probe
User’s and Service Guide
7 Service
Introduction 56
Theory of Operation 58
Troubleshooting Procedures 60
Replacement Procedure 65
Connector Inspection and Cleaning 74
55
7Service
Introduction
Before you troubleshoot
Equipment required for troubleshooting
This chapter contains troubleshooting and repair information. Heed caution signs
to avoid damaging the probe. You may wish to read the “Theory of Operation” on
page 58, with its associated diagrams as an aid to troubleshooting.
Troubleshooting the probe begins with performing the “Operator’s Check” on
page 34, and the Chapter 5, "Performance Tests". If the probe does not pass the
performance tests, refer to the “Troubleshooting Procedures” on page 60.
Troubleshooting procedures require the use of a digital multimeter.
56 Keysight 85024A User’s and Service Guide
Repair strategy
Probe tip, amplifier microcircuit, and regulator assembly
The probe tip and amplifier microcircuit are easily replaced. The regulator
assembly (A1) repair can be performed at either assembly or component level.
Module exchange programs are not available for this product.
Main cable and plastic sleeve guide
The main cable includes the probe wand, the main cable and the smaller power
supply cable. If the cable is damaged, both the cable and the probe wand
assembly must be replaced as a single unit. In this case, take the following parts
off of the old probe for use on the replacement probe:
– The nose assembly
–Nut
– Amplifier microcircuit
These items are shown in Figure 7-6, “Probe end disassembly” on page 66 and
Figure 7-7, “Probe wand components” on page 67
A kit is available that provides a preassembled main cable and probe wand. The
wand does not come with the amplifier microcircuit, nose-assembly, or tip,
because these may be easily removed from your old probe wand. Refer to
Table 6-2, “Replaceable parts” on page 52 for the part number of the kit.
Service 7
Keysight 85024A User’s and Service Guide 57
7Service
Theory of Operation
The probe uses a Gallium Arsenide FET integrated circuit amplifier which provides
unity gain. This amplifier microcircuit requires +6 V and –4 Vdc to operate. These
voltages are provided by the regulator assembly.
The regulator assembly converts the +15 volt and –12.6 volt supplies from the
host instrument with two voltage regulators. The regulator supplies the +6 and –4
voltages to the amplifier microcircuit.
The most common failures in the probe will all result in loss of signal through the
probe, and will show up if the operator’s check is performed. The most common
failures are expected to be:
1 Destruction of the amplifier microcircuit due to static electricity (proper
anti-static precautions not taken).
2 Probe power tip damage (caused by the operator dropping the probe with the
sleeve retracted).
3 Possible regulator failure.
58 Keysight 85024A User’s and Service Guide
ESD protection at the probe tip
The FET integrated circuit amplifier is located at the tip of the probe. The FET
input of the amplifier is protected by a bidirectional voltage limiter as shown in
Figure 7-1.
Figure 7-1 Probe tip input circuit
The voltage limiter element has a negligible effect on circuit operation for input
voltages within specification. The voltage limiter is a non-linear element: it begins
to conduct current at about 2.5 volts. It effectively limits voltages at the amplifier
input to less than ±4 volts. This prevents amplifier damage from low levels of ESD.
Even with the protection provided by the voltage limiter element, the probe is still
sensitive to ESD. High levels of ESD can cause permanent damage to the voltage
limiter element itself. Careful ESD precautions must be observed when using the
probe.
Service 7
Keysight 85024A User’s and Service Guide 59
7Service
CAUTION
Troubleshooting Procedures
The probe contains an input GaAs amplifier microcircuit that is highly
sensitive to electrostatic discharge (ESD). When repairing this probe, you
must use an anti-static wrist strap, and work at a station equipped with an
anti-static surface! Before you take a measurement with a digital
multimeter, discharge the leads by touching them to ground.
Mechanical failure of the protective sleeve
The probe wand/cable must be replaced if the protective sleeve fails to slide and
lock properly.
Electrical failure of the probe
Visually inspect the probe tip
Inspect the probe tip for damage. If it is bent or broken, replace it by referring to
“Replacing the probe tip” on page 65. Perform the “Operator’s Check” on page 34.
If the problem persists, perform the following procedure.
Power supply check
Refer to the probe schematic in Figure 7-2, “A1 regulator schematic diagram and
overall block diagram” on page 61 when performing the following procedure.
1 Check the probe power output from the supplying instrument or power supply.
The output pins and voltages are shown in Figure 7-4, “Power supply check
points” on page 63. Check continuity of the ground pin to chassis ground; it
should be less than 1 W.
– If the supplies are within the tolerances given in “Power requirements” on
page 29 continue to step 2.
– If the voltage is not present at the supplying device, or the ground pin is
open, troubleshoot as required. Suspect a broken wire going to the probe
power jack.
60 Keysight 85024A User’s and Service Guide
Service 7
2 Follow the procedure in “Replacing the amplifier microcircuit” on page 66, to
remove the probe’s nose assembly, amplifier microcircuit, elastic conductive
strip, and spring clip. These items are illustrated in Figure 7-3, “High frequency
probe” on page 62.
Figure 7-2 A1 regulator schematic diagram and overall block diagram
Keysight 85024A User’s and Service Guide 61
7Service
Figure 7-3 High frequency probe
3 Connect the probe’s power cord to the power source. Turn the power source
on.
4 Refer to Figure 7-4. Check the +6 V and –4 V power supply voltages on the
exposed portion of the probe end.
If the voltages are good, suspect an amplifier microcircuit failure. Replace the
amplifier microcircuit and do not perform the following steps.
5 If one of these voltages is bad, follow the procedure in “Removing the plastic
regulator housing covers” on page 67, and continue with the following steps.
6 Refer to Figure 7-4. Disconnect the power supply cable and check the
continuity of the three input lines to the A1 regulator assembly. If one of the
wires is broken internally, replace the cable/probe wand assembly.
7 If the three input lines show continuity, desolder the –4 V and +6 V output
wires shown in Figure 7-4. Measure the +6 V and –4 V feedthroughs on the
printed circuit board. If the voltages are good replace the cable/probe wand
assembly. If one of the voltages is bad, troubleshoot the A1 regulator board.
Refer to Figure 7-5 and Figure 7-2 for a component location diagram and
schematic diagram, respectively.
62 Keysight 85024A User’s and Service Guide
Service 7
Figure 7-4 Power supply check points
Keysight 85024A User’s and Service Guide 63
7Service
Figure 7-5 A1 regulator assembly 85024-6307
[1]
[1] Components on the regulator board are non-purchasable items.
64 Keysight 85024A User’s and Service Guide
Replacement Procedure
CAUTION
CAUTION
NOTE
Replacing the probe tip
Tools required:
– 3/32 inch probe-tip nut driver (supplied with the probe)
– 10 mm open-end wrench
Use static precautions when performing the following procedures. The
amplifier microcircuit is very static sensitive and exposed during this
procedure.
Refer to Figure 7-6.
1 Remove the nut with a 10 mm open-end wrench.
2 Remove the nose assembly, leaving the microcircuit attached to the body of
the probe.
Service 7
Failure to remove the nose assembly prior to replacing the probe tip will
result in damage to the conductive elastomer on the new probe tip
assembly.
3 Unscrew the damaged tip with the nut driver and discard the tip.
4 Screw in the new tip and lightly tighten it with a 3/32 inch nut driver.
(Over-tightening the tip can damage the nose assembly.)
5 Install the nose assembly and nut. Tighten the nut with a 10 mm open-end
wrench.
The tip on the 10:1 divider can be replaced without disassembling the divider.
Use the 3/32 inch probe tip driver.
Keysight 85024A User’s and Service Guide 65
7Service
Figure 7-6 Probe end disassembly
Replacing the amplifier microcircuit
Tools required:
– 10 mm open-end wrench
– Small flatblade screwdriver
Refer to Figure 7-6.
1 Remove the nose assembly.
2 Remove the amplifier microcircuit.
Refer to Figure 7-7.
3 Remove and discard the spring clip and elastic conductive strip.
4 Place the new amplifier microcircuit into the probe heatsink. Place the new
elastic conductive strip in place, making sure the gold traces are facing down
and are aligned lengthwise with respect to the probe. Make sure the elastic
strip is flush with the front end of the heatsink. The screwdriver may be used to
move the strip.
5 Place the new spring clip over the elastic strip, flush with the front of the
heatsink. The beveled end of the clip should face away from the amplifier
microcircuit. The center of this U-shaped clip must press into the elastic
conductor. Insert one side of the clip into the small slot in the probe heatsink.
Press the other side of the clip down with the small screwdriver until it snaps
into the slot on the other side of the heatsink.
6 Replace the nose assembly and nut.
66 Keysight 85024A User’s and Service Guide
Service 7
CAUTION
WARNING
Failure to remove the nose assembly prior to replacing the tip will result in
damage to the conductive elastomer on the tip assembly.
Keysight 85024A User’s and Service Guide 67
Figure 7-7 Probe wand components
Removing the plastic regulator housing covers
Tools required:
– 1/8 inch-wide flatblade screwdriver
In the steps below, hold the regulator housing and screwdriver so that you
won’t injure yourself if the screwdriver slips.
Refer to Figure 7-8.
1 Hold the regulator assembly by one end and insert the head of a 1/8 inch-wide
flatblade screwdriver into the seam at the other end. The seam separates the
two halves of the housing cover. Twist the screwdriver 90°.
7Service
2 Perform step 1 in several places along the four pry points shown in Figure 7-8.
Reassembling the covers
3 Replace the metal housing reinforcement and plastic covers as show in
Figure 6-1, “Replaceable parts identification” on page 53. The reinforcement is
very important; it ensures that the covers will not pop off if the unit is dropped.
Figure 7-8 Cover removal
68 Keysight 85024A User’s and Service Guide
Replacing the type-N output connector
NOTE
Tools required:
– 9/16 inch open-end wrench
Refer to Figure 7-9.
1 Remove the connector body with the open-end wrench.
2 Remove the male center conductor assembly from the gold plated inner
connector. Use your fingers to pull out the assembly. The small insulator may
or may not come out attached to the center conductor assembly. If it does,
remove it from the old center conductor assembly and place it on the new one.
If it is not attached to the center conductor assembly (it remained inside the
inner connector), proceed to step 3.
3 Hold the new center conductor assembly by the large round insulator, not by
the gold plated center conductor. Carefully align the new center conductor
and insert it into the inner connector. Press gently until you feel it click into
place.
4 Place the new connector body and tighten with the open-end wrench.
Service 7
Figure 7-9 Output connector parts
Refer to Chapter 6, “Replaceable Parts” on page 49 for part numbers.
Keysight 85024A User’s and Service Guide 69
7Service
CAUTION
Cable/Probe wand replacement
Tools required:
– 10 mm open-end wrench
– 9/16 inch open-end wrench
– 1/8 inch-wide flatblade screwdriver
– Phillips No. 0 or positive screwdriver
–Long-nose pliers
Special tool:
– Spanner/wrench (part number 85024-20041)?
This special tool is pictured in Figure 7-10, “Special spanner/wrench tool and
area of use” on page 72.
Refer to Figure 7-6.
1 Remove the nut with a 10 mm open-end wrench.
2 Remove the nose assembly and set aside.
The amplifier microcircuit is very sensitive to static electricity. Exercise full
anti-static precautions and use great care when performing the procedure.
Refer to Figure 7-7.
3 Remove the amplifier microcircuit. Remove the spring clip and elastic
conductive strip. Place the microcircuit in a static-safe place. It will be needed
later in this procedure.
4 Remove the regulator housing covers by performing the procedure in
“Removing the plastic regulator housing covers” on page 67.
Refer to Figure 7-9.
5 Remove the connector body with the 9/16 inch wrench.
70 Keysight 85024A User’s and Service Guide
Service 7
Refer to Figure 7-11.
6 Remove the four screws which hold in the regulator assembly. Desolder the
colored wires attached to the regulator assembly and remove the regulator
assembly.
7 Remove the transition nut with the transition nut spanner (shown in
Figure 7-10) and pull the inner connector out of its keyed hole.
8 Unscrew the inner connector from the RF cable. Hold the nut with long nose
pliers while turning the connector.
9 Remove the hex nut with the special cable nut wrench (shown in Figure 7-10).
The cable will now come loose.
10 Insert the new cable into the regulator frame and attach the hex nut.
11 Make sure the insulator (shown in Figure 7-9) is inside the connector.
12 Screw the inner connector onto the new RF cable and insert the inner
conductor into the keyed hole.
13 Attach the transition nut with the spanner wrench.
14 Screw on the connector body and tighten with the 9/16 inch wrench.
15 Solder the seven power supply wires onto the regulator assembly as shown in
Figure 7-11.
16 Attach the A1 regulator assembly to the metal frame with the four screws
removed earlier. The long screws go into the heatsink end.
17 Replace the metal housing reinforcement and plastic covers. The covers and
housing reinforcement are illustrated in the replaceable part chapter, in
Figure 6-1, “Replaceable parts identification” on page 53.
Refer to Figure 7-7.
18 On the new probe wand, place the amplifier microcircuit into the heatsink
assembly. Place the elastic conductive strip in place, making sure the gold
traces are facing down and are aligned lengthwise with respect to the probe.
Make sure the elastic conductor is flush with the front of the heatsink. The
screwdriver may be used to align the strip.
Keysight 85024A User’s and Service Guide 71
7Service
19 Place the spring clip over the conductive strip, flush with the front of the
heatsink. The beveled end of the clip should face away from the front of the
wand. The center of this U-shaped clip must press into the elastic conductor.
Insert one side of the clip into the small slot in the probe heatsink. Press the
other side of the clip down with the small screwdriver until it snaps into the
other slot.
Refer to Figure 7-6.
20 Replace the nose assembly and nut.
Figure 7-10 Special spanner/wrench tool and area of use
72 Keysight 85024A User’s and Service Guide
Service 7
Figure 7-11 Regulator parts and wiring
Keysight 85024A User’s and Service Guide 73
7Service
CAUTION
Connector Inspection and Cleaning
The following is a brief introduction to the fundamentals of proper connector care.
Proper connector care is essential to making accurate valid measurements.
Inspecting the connectors
Visual and mechanical inspection of the output connector and adapter should be
done periodically.
If a bad connector is accidentally attached to a good connector, the good
connector can be damaged.
A connector is bad if one of the following conditions exist:
– It fails the visual examination.
– Connectors do not mate smoothly.
Visual examination
A careful visual inspection should be done often on all device connectors.
Vigilance can save money and ensure the best measurements with your
equipment.
Examine the connectors for such obvious problems as deformed threads,
contamination, or corrosion, concentrating especially on the contacting surfaces.
Look for burrs, scratches, rounded shoulders and similar signs of wear and
damage. Any problem you can see is sufficient to cause degraded performance.
74 Keysight 85024A User’s and Service Guide
Cleaning connectors
CAUTION
WARNING
Always wear an anti-static wrist strap and work on an anti-static bench mat
when cleaning the probe’s outer connectors. Cleaning a connector requires
you to touch the center conductor of the connector with a swab. The danger
of introducing static electricity into the output connector center conductor
must be completely eliminated. Do not clean the adapter when it is
connected to the probe.
Clean connectors are essential for ensuring the integrity of RF and microwave
coaxial connections. Use the following procedure to clean the connectors in this
kit:
1 Use compressed air or nitrogen
Use compressed air (or nitrogen) to loosen particles on the connector mating
plane surfaces. Clean air cannot damage a connector, or leave particles or
residues behind.
Always use protective eyewear when using compressed air or nitrogen.
Service 7
Keysight 85024A User’s and Service Guide 75
You can use any source of clean, dry, low-pressure compressed air or nitrogen
that has an effective oil-vapor filter and liquid condensation trap placed just
before the outlet hose. Ground the hose nozzle to prevent electrostatic
discharge, and set the air pressure to less than 414 kPa (60 psi) to control the
velocity of the air stream. High-velocity streams of compressed air can cause
electrostatic effects when directed into a connector.
2 Clean the connector threads
Use a lint-free swab or cleaning cloth moistened with isopropyl alcohol to
remove any dirt or stubborn contaminants on a connector that cannot be
removed with compressed air or nitrogen.
a Apply a small amount of isopropyl alcohol to the lint-free cleaning swab.
b Clean the connector threads.
c Let the alcohol evaporate, then blow the threads dry with a gentle stream
of clean, low-pressure compressed air or nitrogen.
7Service
WARNING
Isopropyl alcohol is extremely flammable, causes irritation, may cause eye
damage, and is harmful if swallowed or inhaled. It may be harmful if
absorbed through the skin. Keep away from heat, sparks, and flame. Avoid
contact with eyes, skin, clothing. Avoid breathing vapor. Keep in tightly
closed container. Use with adequate ventilation. Wash thoroughly after
handling. In case of fire, use alcohol foam, dry chemical, or carbon dioxide:
water may be ineffective. In case of spill, soak up with sand or earth. Flush
spill area with water.
Dispose of isopropyl alcohol in accordance with all applicable federal, state,
and local environmental regulations.
3 Clean the mating plane surfaces
Apply a small amount of isopropyl alcohol to a new swab and clean the center
and outer conductor mating plane surfaces. When cleaning a female
connector, avoid snagging the swab on the center conductor contact fingers
by using short strokes.
4 Dry the connector
After cleaning, blow the connector dry with a gentle stream of clean
compressed air or nitrogen. Always completely dry a connector before you
reassemble or use it.
5Reinspect
Inspect the connector again to make sure that no particles or residue are
present.
76 Keysight 85024A User’s and Service Guide
Index
Numerics
1 dB compression, 43
10 to 1 divider
, 25
A
accessories, 21
adapter, probe
anti-static precautions
average noise level
, 24
, 17
, 46
C
cable/probe wand
replacement
calibration, response
characteristics
10 to 1 divider, 25
probe adapter
cleaning
10 to 1 divider, 25
connectors
probe adapter
connector
cleaning
inspection
mating
type-N replacement
visual examination
, 70
, 40
, 24
, 74
, 24
, 74
, 74
, 30
, 69
, 74
D
description
10 to 1 divider
average noise level
gain at 500 MHz/frequency re-
sponse flatness, 41
gain compression
median gain
probe adapter
description, product
devices, grounding
divider, 10 to 1
, 25
, 46
, 43
, 41
, 24
, 18
, 33
, 25
E
equipment recommended
test
, 38
equipment required for
troubleshooting, 56
equivalent power
external power supply
, 45
, 29
F
failure
electrical
mechanical
protective sleeve
frequency response relative to 500
MHz, 41
, 60
, 60
, 60
G
gain at 500 MHz, 41
gain compression
general information
grounding devices
, 43
, 15
, 33
I
initial inspection, 28
input voltage for 1 dB
compression, 43
inspection
10 to 1 divider, 25
initial
, 28
probe adapter
installation
, 24
, 27
M
mating connectors, 30
maximum rated input
voltage, 16
measurement precautions
measurements
mechanical failure of the protec-
tive sleeve
, 39
, 60
, 16
median gain
, 41
N
network analyzer
operation
operator’s check
noise level, average
, 39
, 34
, 46
O
operating characteristics
10 to 1 divider
probe adapter
operating instructions
discharging the probe
extending the protective
sleeve, 33
grounding the probe
retracting the protective
sleeve, 33
operating precautions
operation, network analyzer
operator’s check
network analyzer
spectrum analyzer
, 25
, 24
, 33
, 33
, 29
, 34
, 34
, 35
P
parts
identification
miscellaneous
replaceable
performance tests
average noise level, 46
gain at 500 MHz/frequency re-
sponse flatness, 41
input voltage for 1 dB
compression
median gain
power supply
check
external
requirements
precautions
, 53
, 51
, 49, 53
, 43
, 41
, 60
, 29
, 29
, 31
Keysight 85024A User’s and Service Guide 77
anti-static, 17
ESD
, 17
measurement
operating
preparation for use
probe
adapter, 24
check power supply
discharging between
measurements, 33
electrical failure
grounding
inspection
mechanical failure
sleeve
tip replacement
visually inspect the tip
procedure
average noise level, 46
gain at 500 MHz/frequency re-
sponse flatness
gain compression
input voltage for 1 dB
compression
median gain
operator’s check
operator’s check using a net-
work analyzer, 34
operator’s check using a spec-
trum analyzer
replacement
troubleshooting
product
10 to 1 divider, 25
probe adapter
product description
average noise level
gain at 500 MHz/frequency re-
sponse flatness
gain compression
median gain
probe adapter
protective sleeve
extension of, 33
retraction of
, 16
, 32
, 29
, 60
, 60
, 33
, 24
, 60
, 33
, 26, 65
, 41
, 43
, 43
, 41
, 34
, 35
, 65
, 60
, 24
, 18
, 46
, 41
, 43
, 41
, 24
, 33
, 60
R
recommended test
equipment
repair strategy
main cable and plastic sleeve
guide
probe tip and amplifier
microcircuit, 57
replaceable parts
adapter, 26
probe
replacement procedure
amplifier microcircuit
cable/probe wand
plastic regulator covers and
housing, 67
probe tip
type-N connector
required equipment for
troubleshooting, 56
response calibration
returning the product for
service, 30
, 38
, 57
, 57
, 24, 26, 52
, 65
, 66
, 70
, 26, 65
, 69
, 40
S
S21 measurement, 39
service
, 55
settings
frequency range, 39
output power
power meter
spectrum analyzers, operator’s
check, 35
, 40
, 39
T
test equipment, 38
test procedure
average noise level
gain at 500 MHz/frequency re-
sponse flatness, 41
input voltage for 1 dB
compression, 43
median gain
operator’s check using a net-
work analyzer, 34
, 46
, 41
operator’s check using a spec-
trum analyzer
test record
tests, performance
theory of operation
transmission measurement
troubleshooting
troubleshooting and repair
troubleshooting equipment
troubleshooting procedure
type-N output connector
replacement
, 47
electrical failure
mechanical failure of the pro-
tective sleeve, 60
power supply
visual inspection of the probe
tip, 60
visually inspect the tip
mechanical failure of the pro-
tective sleeve, 60
power supply
visually inspect the probe
tip, 60
, 35
, 37
, 58
, 39
, 55, 60
, 60
, 60
, 60
, 55
, 56
, 60
, 60
, 69
V
visually inspect the probe tip, 60
78 Keysight 85024A User’s and Service Guide
This information is subject to change
without notice. Always refer to the
Keysight website for the latest
revision.
© Keysight Technologies 2014 - 2018
Edition 2, September 24, 2018
Printed in Malaysia
*85024-90031*
85024-90031
www.keysight.com
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