236 Receiver Fault Finding TM9100 Service Manual
© Tait Electronics Limited August 2005
Task 9 —
Slightly Low
Sensitivity
Following the initial investigation in Task 7, check the circuitry as follows
when the sensitivity loss is slight.
1. Remove the
FE TOP can and, if not already done, the IF TOP can.
2. Check the soldering of all the components of the front-end tuning
circuitry from C400 to T401 (see Figure 10.1 and Figure 10.3).
3. Check the IF-amplifier bias conditions as in Step 4 and Step 5 of
Task 5
.
4. Check the LNA bias conditions as in Step 4 and Step 5 of Task 8
.
5. If the checks of Step 2 to Step 4 reveal no fault, go to Step 6. If there
is a fault, repair it and go to Step 7.
6. Check the PIN switch and LPF as in Task 31
to Task 33 of
“Transmitter Fault Finding (50W/40W Radios)” on page 245 or
“Transmitter Fault Finding (25W Radios)” on page 315.
7. Recalibrate the receiver using the calibration application.
8. Confirm the removal of the fault and go to “Final Tasks” on
page 147. If the repair failed, replace the main-board assembly and go
to “Final Tasks” on page 147.
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