HP 8560A, Service Manual

Page: 294 / 450

Performance Test Failures
Failures in IF-Section-related performance tests may be investigated using the following
information.
IF Gain Uncertainty Performance Test
Failure of this performance test indicates a possible problem with the spectrum analyzer IF
gain circuits. Assuming no major IF problems causing IF adjustment errors, IF gain problems
in the first 50
of IF gain (REF of 0 to -50 with 10 are a
result of faults on the A5 IF Assembly. IF gain problems in the next 60 of IF gain (REF
of -60 to -110 10 result from faults on the A4 Log Amplifier
assembly.
Table 8-4 lists the reference level range available in each band with 0 input attenuation.
Table 8-5 lists the input required at for displaying a signal at top screen with 10
input attenuation and a 0 reference level.
Table 8-4. Available Reference Level Range
Band Frequency Range Ref. Level
Table 8-5. Signal Level for Reference Level Display
Baud Frequency Input at
(0 Input
0 0 to 2.9 - 5
Isolate IF gain problems on A4 Log Amplifier assembly with the following steps:
1. On the spectrum analyzer press ZERO SPAN
,(
frequenc
yw), 1
(AMPLITUDE),
Press
(CAL), IF ADJ OFF.
3. Disconnect cable W27 (coax 3) from and connect cable W27 to the output of a signal
generator.
8-12 IF Section