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k.
If the sampler, photodiode, and amplifier are working properly, the oscilloscope display
will show the trace switch between two distinct levels. See Figure 8-14 below. With
continued observation these levels, which correspond to F1 and F2, will change
amplitudes since the tuning is uncontrolled. The difference between the levels varies
with time between a maximum difference and a minimum difference.
l.
Disconnect the test equipment and set HEATER jumper JMP7 to NRM. Set TEST-NORM
switch to NORM and replace HP5501B covers.
8-67. Testing the Liquid Crystal Switch
8-68.
The following material and test equipment is required for the test:
a.
A white piece of cardboard.
b.
50 Hz Square Wave Generator (TTL Level)
c.
Test Polarizer (HP Part Number 1000-0616)
8-69.
To test the liquid crystal, proceed as follows:
a.
Remove the liquid crystal from the sampler assembly as shown in Figure 8-15 below:
Figure 8-14. Quick Tuning Check Waveform Display
Figure 8-15. Liquid Crystal Removal
HP5501B
Service
8-21
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Table of Contents
Troubleshooting
