89410A-03
SUPERSEDES: None
DATE: 01 June 1993
89410A Vector Signal Analyzer
Serial Numbers: See text for all applicable serial numbers.
Calibration failures caused by ADC shorting to heat sink
Duplicate Service Notes: 89410A-03, 89440A-03
To Be Performed By: Agilent-Qualified Personnel
Parts Required:
Part No. Description
89410-44101 Silpad insulator
Situation:
Analyzers with an IF section serial number less than 3313A00220 may have calibration
failures caused by the IF section’s ADC shorting to its bottom heat sink. To solve this
problem, an insulator needs to be placed between the A20 U17 ADC and its bottom heat
sink.
Solution/Action:
Install a silpad insulator which is thermal conductive between the IF section’s A20 U17
ADC and its bottom heat sink.
1 of 2
AUTHOR: CMG
ENTITY: A100
© 1993 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: 01 June 1995
ADDITIONAL INFORMATION:
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 1.0 Hour
Continued
Page 2 Service Note 89410A-03
If the analyzer has the optional second IF channel, perform steps for channel 1, then
repeat steps for channel 2. Do not mix the A20 A/D Converter assemblies between
channels. If the A/D Converter assemblies are mixed between channels, the adjustments for the Input and A/D Converter assemblies will need to be done.
CAUTION
The following steps must be performed at a static protected site
to prevent static discharge damage during the handling of the
PC assembly.
STEP 1. Remove A/D assembly.
1. Set the IF section’s power switch to OFF and remove the top cover.
2. Remove the card nest screws from the A20 A/D Converter assembly. See
Replacing Assemblies in the 89440A Service Guide.
Figure 1
Page 3
STEP 2. Install the silpad under A20 U17.
1. Remove the heat sink on top of A20 U17 using a T-8 Torx screw driver.
2. Remove A20 U17 from its socket.
3. Place the silpad on the bottom of A20 U17.
4. Install A20 U17 in its socket and replace the top heat sink.
STEP 3. Replace the A10 A/D Converter assembly in its card nest.
STEP 4. Connect the A10 and A20 cables as follows using the original SMB
cables:
Channel 1:
Red cable A10 J2 to A20 J4
Orange cable A10 J3 to A36 J2
Yellow cable A20 J1 to A60 J3
Channel 2:
Red cable A10 J2 to A20 J4
Orange cable A10 J3 to A36 J5
Yellow cable A20 J1 to A60 J2
STEP 5. Clear the fault log and perform the self test by pressing the following
keys:
[ System Utility ]
[ more ]
[ diagnostics ]
[ service functions ]
1125
[ enter ]
[ fault log ]
[ clear fault log ]
[ Return ]
[ test log ]
[ Return ]
[ functional tests ]
[ ALL ]
It takes about 2 minutes for the analyzer to run the long confidence self test.
STEP 6. Replace the A/D Converter’s card nest screws and the top cover.
Service Note 89410A-03
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