208 Frequency Synthesizer Fault Finding TM8100/TM8200 Service Manual
© Tait Electronics Limited June 2006
Task 19 —
Repair Receive VCO
If either or both the minimum and maximum receive frequencies are
incorrect, the receive VCO circuitry is faulty.
1. Remove the
VCO TOP can.
2. Check the receive VCO. The circuitry is based on Q504
(see Figure 9.10).
3. If a fault is found, repair it and go to Step 4. If no fault is found, go
to Step 6.
4. Repeat the frequency measurements in Step 2 and Step 4 of Tas k 17
.
5. If the frequencies are now correct, resolder R542 in position
(see Figure 9.10), and go to “Final Tasks” on page 157. If they are
still not correct, go to Step 6.
6. Resolder R542 in position (see Figure 9.10). Replace the board and
go to “Final Tasks” on page 157.