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MAINTENANCE
4.3.4.13
10.7 MHz Filter, A4A1, (791594) Switch Testing and Troubleshooting
10.7 MHz Filter Switch Testing and Troubleshooting includes a checkout
procedure and fault isolation information.
A Signal Generator and an RF Voltmeter
(Table 4-1) are 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 4-12 for fault isolation.
1.
Deenergize the receiver.
2.
Disconnect connector P19 from A4XA1.
3.
Place PC board A4A1 in an extender.
4.
Select the 3.2 kHz BW position.
5.
Connect the RF Voltmeter to A4XA1 pin 57 using a
short coaxial cable with clip leads on one end.
6.
Connect the Signal Generator to A4XA1 pin 13 using a
short coaxial cable with clip leads on one end.
Set the
Generator output frequency to 10.7 MHz and output
level to -27 dBm.
7.
Energize the receiver. The RF Voltmeter should display
a level of 50 mV.
8.
Select the 6 kHz BW and then the 50 kHz BW positions.
The RF Voltmeter should display a level of 50 mV in
both BW position.
8.
Check the Test Points given in Table 4-12 with an RF
Voltmeter and high impedance probe. When a faulty
signal is encountered, replace the key components
indicated and
repeat
the Checkout Procedure.
Figure 6-15, 10.7 MHz Filter Switch Schematic Diagram,
should be referred to if additional signal tracing/fault
isolation is necessary.
9.
When the 10.7 MHz Filter Switch has been repaired and
is operating satisfactorily, deenergize the receiver and
disconnect test equipment, if no further tests are to be
performed.
4-29
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