Agilent Technologies 8498A Service manual

8498A
Fixed Attenuator
Operating and Service
Manual
Agilent Part Number: 08498-90008
Printed in USA
Print Date: April 2001
Supersedes: February 1999
The contents of this manual apply
to instruments with serial number
prefix US91 and above.

ii Agilent Technologies 8498 Operating and Service Manual
Notice
The information contained in this document is subject to change without
notice.
Agilent Technologies makes no warranty of any kind with regard to this
material, including, but not limited to, the implied warranties of
merchantability and fitness for a particular purpose. Agilent Technologies
shall not be liable for errors contained herein or for incidental or
consequential damages in connection with the furnishing, performance, or
use of this material.
Agilent Technologies assumes no responsibility for the use or reliability of
its software on equipment that is not furnished by Agilent Technologies.
This document contains proprietary information which is protected by
copyright. All rights are reserved. No part of this document may be
photocopied, reproduced, or translated to another language without prior
written consent of Agilent Technologies.
Restricted Rights Legend
Use, duplication, or disclosure by the U.S. Government is subject to
restrictions as set forth in subparagraph (c)(1)(ii) of the Rights in Technical
Data and Computer Software clause at DFARS 252.227-7013 for DOD
agencies, and subparagraphs (c)(1) and (c)(2) of the Commercial Computer
Software Restricted Rights clause at FAR 52.227-19 for other agencies.
Agilent Technologies, Inc
Santa Rosa Systems Division
1400 Fountaingrove Parkway
Santa Rosa, CA 95403-1799, U.S.A.
© Copyright 1997, 1999, 2001 Agilent Technologies, Inc.

Agilent Technologies 8498 Operating and Service Manual iii
Warranty
Certification Agilent Technologies certifies that this product met its published specifications at the time of
shipment from the factory. Agilent Technologies further certifies that its calibration
measurements are traceable to the United States National Institute of Standards and
Technology (NIST, formerly NBS), to the extent allowed by the Institute’s calibration facility,
and to the calibration facilities of other International Standards Organization members.
Warranty This Agilent Technologies system product is warranted against defects in
materials and workmanship for a period corresponding to the individual
warranty periods of its component products. Instruments are warranted for a
period of one year. During the warranty period, Agilent Technologies will, at
its option, either repair or replace products that prove to be defective.
Warranty service for products installed by Agilent Technologies and certain
other products designated by Agilent Technologies will be performed at
Buyer’s facility at no charge within Agilent Technologies service travel
areas. Outside Agilent Technologies service travel areas, warranty service
will be performed at Buyer’s facility only upon Agilent Technologies’s prior
agreement and Buyer shall pay Agilent Technologies’s round trip travel
expenses. In all other areas, products must be returned to a service facility
designated by Agilent Technologies.
For products returned to Agilent Technologies for warranty service, Buyer
shall prepay shipping charges to Agilent Technologies and Agilent
Technologies shall pay shipping charges to return the product to Buyer.
However, Buyer shall pay all shipping charges, duties, and taxes for products
returned to Agilent Technologies from another country.
Agilent Technologies warrants that its software and firmware designated by
Agilent Technologies for use with an instrument will execute its
programming instructions when properly installed on that instrument.
Agilent Technologies does not warrant that the operation of the instrument,
or software, or firmware will be uninterrupted or error free.
LIMITATION OF WARRANTY. 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. AGILENT
TECHNOLOGIES SPECIFICALLY DISCLAIMS THE IMPLIED
WARRANTIES OR MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE.

iv Agilent Technologies 8498 Operating and Service Manual
EXCLUSIVE REMEDIES. THE REMEDIES PROVIDED HEREIN ARE
BUYER’S SOLE AND EXCLUSIVE REMEDIES. AGILENT
TECHNOLOGIES SHALL NOT BE LIABLE FOR ANY DIRECT,
INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
DAMAGES, WHETHER BASED ON CONTRACT, TORT, OR ANY
OTHER LEGAL THEORY.
Assistance Product maintenance agreements and other customer assistance agreements
are available for Agilent Technologies products.
For assistance, call your local Agilent Technologies Sales and Service Office
(refer to “Service and Support” on page v).

Agilent Technologies 8498 Operating and Service Manual v
Service and Support
By internet, phone, or fax, get assistance with all your test and measurement
needs.
Online assistance: www.agilent.com/find/assist
United States
(tel) 1 800 452 4844 Latin America (tel) [phone]
(fax) [phone]
Canada
(tel) 1 877 894 4414
(fax) [phone]
Europe
(tel) ([phone]
(fax) ([phone]
New Zealand
(tel) 0 800 738 378
(fax) ([phone]
Japan
(tel) ([phone]
(fax) ([phone]
Australia
(tel) 1 800 629 485
(fax) ([phone]
Asia Call Center Numbers
Country Phone Number Fax Number
Singapore 1-800-375-8100 (65) 836-0252
Malaysia 1-800-828-848 1-800-801664
Philippines (632) 8426802
1-800-16510170 (PLDT
Subscriber Only)
(632) 8426809
1-800-16510288 (PLDT
Subscriber Only)
Thailand [phone] (outside Bangkok)
[phone] (within Bangkok) (66) 1-661-3714
Hong Kong 800-930-871 (852) 2506 9233
Taiwan 0800-047-866 (886) 2 25456723
People’s Republic
of China 800-810-0189 (preferred) 10800-650-0021 10800-650-0121
India 1-600-11-2929 000-800-650-1101

vi Agilent Technologies 8498 Operating and Service Manual
Safety and Regulatory Information
Review this product and related documentation to familiarize yourself with
safety markings and instructions before you operate the instrument. This
product has been designed and tested in accordance with international
standards.
WARNING The WARNING notice denotes a hazard. It calls attention to a procedure,
practice, or the like, that, if not correctly performed or adhered to, could result
in personal injury. Do not proceed beyond a WARNING notice until the
indicated conditions are fully understood and met.
CAUTION The CAUTION notice denotes a hazard. It calls attention to an operating
procedure, practice, or the like, which, 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.
Instrument Markings
When you see this symbol on your instrument, you should refer to the instrument’s
instruction manual for important information.
This symbol indicates hazardous voltages.
The laser radiation symbol is marked on products that have a laser output.
This symbol indicates that the instrument requires alternating current (ac) input.
The CE mark is a registered trademark of the European Community. If it is
accompanied by a year, it indicates the year the design was proven.
The CSA mark is a registered trademark of the Canadian Standards Association.
1SM1-A This text indicates that the instrument is an Industrial Scientific and Medical Group 1
Class A product (CISPER 11, Clause 4).
This symbol indicates that the power line switch is ON.
This symbol indicates that the power line switch is OFF or in STANDBY position.
!

Agilent Technologies 8498 Operating and Service Manual vii
Safety and Regulatory Information
Safety Earth
Ground This is a Safety Class I product (provided with a protective earthing
terminal). An uninterruptible safety earth ground must be provided from the
main power source to the product input wiring terminals, power cord, or
supplied power cord set. Whenever it is likely that the protection has been
impaired, the product must be made inoperative and secured against any
unintended operation.
Before Applying Power Verify that the product is configured to match the available main power
source as described in the input power configuration instructions in this
manual. If this product is to be powered by autotransformer, make sure the
common terminal is connected to the neutral (grounded) side of the ac power
supply.

viii Agilent Technologies 8498 Operating and Service Manual
Typeface Conventions
Typeface Conventions
Italics •Used to emphasize important information:
Use this software
only with the xxxxxX system.
•Used for the title of a publication:
Refer to the xxxxxX System-Level User’s Guide.
•Used to indicate a variable:
Type LOAD BIN filename.
Instrument Display •Used to show on-screen prompts and messages that you will see on the
display of an instrument:
The xxxxxX will display the message CAL1 SAVED.
[Keycap] •Used for labeled keys on the front panel of an instrument or on a
computer keyboard:
Press [Return].
{Softkey} •Used for simulated keys that appear on an instrument display:
Press {Prior Menu}.
User Entry •Used to indicate text that you will enter using the computer keyboard;
text shown in this typeface must be typed
exactly as printed:
Type LOAD PARMFILE
•Used for examples of programming code:
#endif // ifndef NO_CLASS
Path Name •Used for a subdirectory name or file path:
Edit the file
usr/local/bin/sample.txt
Computer Display •Used to show messages, prompts, and window labels that appear on a
computer monitor:
The Edit Parameters window will appear on the screen.
•Used for menus, lists, dialog boxes, and button boxes on a computer
monitor from which you make selections using the mouse or keyboard:
Double-click EXIT to quit the program.

Contents
Agilent Technologies 8498A Operating and Service Manual Contents 1
Notice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
Service and Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .v
Safety and Regulatory Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
Safety Earth Ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Before Applying Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .vii
Typeface Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Attenuator Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Safety Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Table 1. Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Table 2. Supplemental Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . 2
Operating Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Storage and Shipping Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Mating Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Figure 1. Type N Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Initial Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Preparation For Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Operating Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Operator’s Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Performance Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 2. Attenuator Exploded View. . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 3. Replaceable Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 4. Attenuator Cartridge Assembly Parts (Item 16 in Figure 2) . 9

Agilent Technologies 8498A Operating and Service Manual 1
General Information
Attenuator Overview The 8498A is a 30 dB, 30 W (25 W between +35° ×C and + 55°C) fixed
attenuator with Type N connectors. Either connector may be used as the
input or output connector.
•The attenuator is designed to work in a 50 ohm system, and operates
over the frequency range from dc to 18.0 GHz.
•The attenuator may be used (1) to reduce a high power signal to a level
that is compatible with sensitive equipment, (2) to reduce reflections, or
(3) as a known attenuation for substitution.
Instruments Covered By Manual
The attenuators covered by this manual have a two-part serial number. The
first four characters constitute the serial number prefix. The remaining digits
form the sequential suffix that is unique to each attenuator.
The contents of this manual apply directly to the attenuators having the serial
prefix US91. An attenuator manufactured after the printing of this manual
may have a serial prefix that is not noted above. This unlisted serial prefix
indicates that the attenuator differs in some respect from the information in
this manual.
Warranty
The attenuator is warranted and certified as indicated on the warranty page
of this manual. For further information, contact the nearest Agilent
Technologies Sales and Service office. Refer to “Service and Support” on
page v.
The attenuator is warranted only when it is operated within its specifications.
This is especially true of power handling capability. Any attenuator returned
to Agilent Technologies under warranty will be examined carefully to
determine if the failure was possibly due to improper use.
Safety Considerations The warning that follows is related to possible personal injury.
WARNING The high power attenuator card has a substrate of beryllium oxide. Beryllium
oxide in a powder form is a hazardous material and may be injurious to your
health if inhaled. Do not perform any operation on the beryllium oxide that
might generate dust. Defective attenuator cards should be returned to Agilent
Technologies for proper disposal.