196 Frequency Synthesizer Fault Finding TM9100 Service Manual
© Tait Electronics Limited August 2005
Task 18 —
Repair PLL feedback
If both the minimum and maximum receive frequencies are correct, the
PLL feedback is suspect.
1. Resolder R542 in position (see Figure 9.9).
2. Remove the
VCO BOT can.
3. Replace the components C567, R574 (see Figure 9.10) and IC503
(see Figure 9.9).
4. Also check the second stage of the receive buffer amplifier based on
IC5100 (see Figure 9.10). Repair any fault.
5. Confirm that the fault in the radio has been removed. If it has, go to
“Final Tasks” on page 147. If it has not, replace the main-board
assembly and go to “Final Tasks” on page 147.
Figure 9.10 Synthesizer circuitry under the VCO BOT can
(UHF radio, bottom side)
Q5001
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