8920A-04
SUPERSEDES: None
Continued
DATE: 26 May 1992
8920A RF Communications Test Set
Serial Numbers: 3010A00226 / 3123A00305
Modification to Resolve Low Sensitivity Problem of Antenna Input
Parts Required:
08920-69004, Exchange Assembly, A23 Input Section
Situation:
A problem has been noted in the A23 Input Section assembly which causes the overpower
protection circuitry on the Antenna Input to randomly trigger. This opens a relay in series
with the Antenna Input which causes a drop in the measured signal level of 20 dB.
Instruments with firmware revision A.05.01 or later will detect this condition and issue a
two-tone beep and display the following message on the CRT:
“ANT IN OVERPOWER. REDUCE INPUT POWER AND PUSH MEAS RESET.”
Pressing the MEAS RESET key will reset this condition, but the next random trigger will
initiate another overpower detection sequence. NOTE: Earlier versions of firmware will
not indicate to the user that an overpower condition has been detected and triggered.
1 of 2
AUTHOR: L.H.L
ENTITY: 1000
© 1992 AGILENT TECHNOLOGIES
PRINTED IN U.S.A.
SERVICE NOTE
ADMINISTRATIVE INFORMATION
MODIFICATION RECOMMENDED
SERVICE NOTE CLASSIFICATION:
ACTION
CATEGORY:
LOCATION
CATEGORY:
CUSTOMER INSTALLABLE
ON-SITE
SERVICE CENTER
AGILENT RESPONSIBLE UNTIL: 1 July 1997
ADDITIONAL INFORMATION: Utilize standard SMO Exchange
Assembly process.
IMMEDIATELY
ON SPECIFIED FAILURE
AGREEABLE TIME
AVAILABILITY:
PRODUCT’S SUPPORT LIFE
RETURN
SCRAP
SEE TEXT
SERVICE
INVENTORY:
RETURN
SCRAP
SEE TEXT
USED
PARTS:
STANDARDS:
Labor 2.0 Hour
Page 2 Service Note 8920A-04
The following instruments are affected by this problem:
8920A Serial Numbers:
3010A00226
3010A00233-235
3010A00237-246
3119A00247-268
3119A00270-279
3123A00280-282
3123A00285
3123A00287-295
3123A00297
3123A00300
3123A00303-305
Solution/Action:
The A23 Input Assembly has been redesigned to solve this problem. Replace the A23
Input Assembly with an exchange assembly (see Parts Required). Chapter 10 of the
8920A Assembly Level Repair Manual contains removal and installation instructions for
the A23 assembly. Re-calibration of the instrument is not required.
Check the date code on the A23 assembly before implementing this Service Note. Only
A23 assemblies with date code 3049A, 3118A, 3120A, 3123A and 3124A have this
problem. The date code is located on a label attached to the assembly’s aluminum housing. Refer to the figure below to identify the date Code:
Loading...