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MAINTENANCE
WJ-8718-19/FE HF RECEIVER
4.3.4.4
1st LO Synthesizer, FE-A1A1A1, (370689) Testing and Troubleshooting
1st LO Synthesizer Testing and Troubleshooting includes a checkout
procedure and fault isolation information. An oscilloscope (see Table 4-1) is required
to perform the tests outlined below.
Perform the following procedure in the sequence given. If any specified
result is not obtained, refer to Table 4-5 for fault isolationn
1.
Deenergize the receiver.
2.
Obtain access to module FE-A1A1A1.
Connect the
oscilloscope to terminal ElOn
3.
Set the receiver front panel controls as follows:
a.
Gain Mode-
Manual
b.
RF Gain
-
Maximum Clockwise
4.
Energize the receiver and tune to 42.0000 MHz.
5.
The oscilloscope should display a level of +3 Vdc.
6.
IF the signal in step 5 is incorrect, check the Test
Points given in Table 4-5 with an oscilloscope and high
impedance probe. When a faulty signal is encountered,
replace the key components indicated and repeat the
Checkout Procedure.
Figure 6-4, 1st LO Synthesizer
Schematic Diagram should be referred to if additional
signal tracing/fault isolation is necessary.
9.
When the 1st LO Synthesizer has been repaired and is
operating satisfactorily, deenergize the receiver and
disconnect test equipment, if no further tests are to be
performed.
4-18
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