Tait TM8100 mobiles - Page 254

254 Receiver Fault Finding TM8100/TM8200 Service Manual
© Tait Electronics Limited November 2007
Task 6 —
Check Matching
Circuitry
Having excluded the IF amplifier, check the matching circuitry for the
crystal filters.
1. Check all remaining components between T401 and IC400 — these
form the matching circuitry for the crystal filters XF400 and XF401
(see Figure 10.1).
2. If the above check reveals no fault, go to Step 3. If there is a fault,
repair it and go to Step 6.
3. Remove the
PIN TOP and LPF TOP cans.
4. Make a visual check of the components in the receive path of the PIN
switch and LPF circuits.
5. If the visual check reveals an obvious fault, repair it and go to Step 6.
If there is no obvious fault, go to Task 7
.
6. Recalibrate the receiver using the calibration application.
7. Confirm the removal of the fault, and go to “Final Tasks” on
page 163. If the repair failed go to Ta s k 7
.