1-74
Troubleshooting the Analyzer
To troubleshoot input and ADC failures
Time/div 200 ns/div
Probe Atten 1
h Connect a high impedance 1:1 oscilloscope probe to A91 J6 pin
29B.
The signal should be 423 ±42 mVp-p.
i If the signal is incorrect, the A35 Analog Source assembly is
probably faulty.
5 Check the frequency sample signals.
a Reconnect A10 J2 to A21 J4.
b Place the analyzer on the side closest to the display.
c Remove the bottom cover.
d Press
[Preset].
e Using a logic probe, check that the TTL signals listed in the
following table are toggling.
f If the signals are incorrect, the A60 Frequency Reference
assembly is probably faulty.
g If the signals are correct, the A21 A/D Converter assembly is
probably faulty.
This test does not check the A71 Pass Through assembly. The
Pass Through assembly buffers the signals from the A21 A/D
Converter assembly before they go to the A50 Digital Filter
assembly. There is a separate set of buffers for each channel. The
Pass Through assembly is less likely to fail than the A21 A/D
Converter assembly.
h If the calibration error message is ‘’Channel 1 fails flatness test,’’
the A50 Digital Filter assembly may be failing even though the
digital filter self test passes.
If replacing the A21 A/D Converter assembly does not fix the
failure, the A71 Pass Through assembly or A50 Digital Filter
assembly is probably faulty.
Test Location Signal Name
A91 P6 pin 4 FSAAD
A91 P6 pin 11 FSA2
A91 P6 pin16 FSA1
To Next Page
Loading...
Need help?
General
