Tait TP9100 - Page 133

TP9100 Service Manual Servicing Procedures 133
© Tait Electronics Limited May 2005
13. After having eliminated the synthesizer, the transmitter circuitry, and
the speaker as cause for the fault, repair the radio as described in
“CODEC and Audio ault Finding” on page 269.
14. If the main board was replaced or if the repair failed, re-assemble the
radio as described in “Reassembling the Radio” on page 112.
Conclude with the tasks of “Final Tasks” on page 134.
Task 10 —
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 159.
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
■ 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.
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 134.
If it does not, repair the radio as described in “Receiver Fault
Finding” on page 251.
9. Check whether the speaker is the source of the fault, as described in
“Internal Speaker/ Microphone Faulty” on page 146.
10. If the radio receives audio now, the original speaker was faulty.
Reassemble the radio and go to “Final Tasks” on page 134. If the