Agilent Technologies HP 8719D Service Manual page 246

Assembly Replacement Sequence
The following steps show the sequence to replace an assembly in the network
analyzer.
1. Identify the faulty group. Refer to Chapter 4, "Start Troubleshooting Here. n
Follow up with the
faulty assembly.
2. Order a replacement assembly. Refer to Chapter 13, "Replaceable Parts."
3. Replace the faulty assembly and determine what adjustments are necessary.
Refer to Chapter 14, "Assembly Replacement and Post-Repair Procedures."
4. Perform the necessary adjustments. Refer to Chapter 3, "Adjustments and
Correction Constants. n
5. Perform the necessary performance tests. Refer to Chapter 2, "System
Verification and Performance Tests. n
All Signal Paths Look Abnormal
For the receiver to operate properly, the A10 digital IF and 2nd converter
assemblies must receive signals from the Al2 assembly. Those signals are the
Press
. . . .
the analog bus counter.
If the counter reads 9.996 MHz, continue with "4 MHz Check.'
n
If the counter does not read 9.996 MHz, perform the "A12 VCO Tune
n
Adjustment. n
If the adjustment is successful and the problem is cured, perform the
q
"Frequency Accuracy Performance Test" for verification.
If the adjustment is unsuccessful or the problem persists, replace the Al2
q
assembly.