Troubleshooting Guide
8500C/8500C+ System Maintenance Manual
5-41
Table 5-11. 8520C Signal Selector Tests
Problem
Solution
5.5.2.3 amplitude, Frequency, and Phase
Accuracy Test
Vibration level, frequency reading, or phase
angle does not meet specifications.
1. Check 8520C harness assembly
(Figure 5-19) for shorted or open
connections which can be caused by loose
or pinched wires, unplugged connectors, or
worn-through insulation.
2. Disconnect 8520C and retest according to
5.5.1.3, “Amplitude, Frequency, and Phase
Accuracy Tests.”
3. If 5.5.1.3, “Amplitude Frequency, and
Phase Accuracy Tests, “ pass, 8520C is
most likely at fault. Replace 8520C
controller board (Figure 5-19, A1).
5.5.2.4 Channel Crosstalk Test
Noise signal above .01 IPS is displayed.
1. Disconnect 8520C and retest according to
5.5.1.4, “Noise and Spurious Signals Test.”
2. If 5.5.1.4, “Noise and Spurious Signals
Test,” passes, 8520C is most likely at fault.
Replace 8520C controller board
(Figure 5-19, A1).
