156 Servicing Procedures TM8100/TM8200 Service Manual
© Tait Electronics Limited June 2006
14. If the main-board assembly was replaced or if the repair failed, re-
assemble the radio as described in “Disassembly and Reassembly” on
page 129. Conclude with the tasks of “Final Tasks” on page 157.
Task 1 0 —
Check the Receive
and Receive-Audio
Functions
If the radio does not receive, this can be caused by:
■ the synthesizer not being in lock
■ no carrier detected
■ a faulty speaker or volume control
■ no modulation.
If the cause is already known, go directly to the relevant fault-finding
section.
1. Use CCTM command 101 x y 0 to set the receive frequency to the
bottom of the band.
2. Use CCTM command 72 to read the lock status.
3. If the synthesizer is in lock, go to Step 5. If the synthesizer is not in
lock, repair the radio as described in “Frequency Synthesizer Fault
Finding” on page 179.
4. Repeat Step 1 to Step 3 with the receive frequency set to the top of
the band
5. Feed a signal without modulation on the receive channel at –47dBm.
Check for maximum RSSI using:
■ the indicator on the radio display (graphical display)
■ the green status LED
■ CCTM command 63 should return the fed signal strength
±1dBm.
6. Repeat the check in Step 5 with –117dBm. The RSSI indicator
should show as empty or close to empty (graphical display).
7. If the carrier is detected correctly, go to Step 9. If the carrier is not
detected correctly, try to re-calibrate the radio.
8. If the re-calibration repairs the fault, go to “Final Tasks” on page 157.
If it does not, repair the radio as described in “Receiver Fault
Finding” on page 239.
9. Check whether the speaker is the source of the fault, as described in
“Speaker Faulty” on page 422 (graphical display) or “Speaker Faulty”
on page 436 (1-, 2- or 3-digit display).
10. If the radio receives audio now, the original speaker was faulty.
Reassemble the radio and go to “Final Tasks” on page 157. If the
radio still fails to receive, reconnect the original speaker and go to
Step 11.
11. Use CCTM command 804 to read the status of the volume
potentiometer.
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