Tait TM8100 mobiles Service Manual page 161

Task 9 —
Check the Transmit
and Transmit-Audio
Functions
TM8100/TM8200 Service Manual
© Tait Electronics Limited November 2007
If the radio does not transmit, this can be caused by:
the synthesizer not being in lock
■
no or wrong carrier power
■
no modulation.
■
If the cause is already known, go directly to the relevant fault-finding
section.
Caution
Observe the servicing precautions for transmitter
issues listed
Use CCTM command 101 x y 0 to set the transmit frequency to the
1.
bottom of the band.
Use CCTM command 33 to set the radio to transmit mode.
2.
Use CCTM command 72 to read the lock status.
3.
4. If the synthesizer is in lock, go to
lock, repair the radio as described in
Finding" on page
5. Repeat Step 1 to
the band.
Use CCTM command 326 1 to set the power level to very low.
6.
7. Connect a power meter and measure the transmit power.
8. If the carrier power is correct, go to
not correct, try to re-calibrate the radio.
9. If the re-calibration repairs the fault, go to
If it does not, repair the radio as described in
Finding (>25W)" on page 267
(25W)" on page
10. Repeat Step 6 to
11. Check whether the speaker is the source of the fault, as described in
"Speaker Faulty" on page 440
on page 454 (1-, 2- or 3-digit display).
12. If the radio transmits audio now, the original speaker was faulty.
Reassemble the radio and go to
radio still fails to transmit, reconnect the original speaker and go to
Step 13.
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 Fault Finding" on page
on page 113.
Step
"Frequency Synthesizer Fault
185.
Step 4 with the transmit frequency set to the top of
Step
and "Transmitter Fault Finding
341.
with the power level set to high (326 4).
Step 9
(graphical display) or
"Final Tasks" on page
5. If the synthesizer is not in
10. If the carrier power is
"Final Tasks" on page
"Transmitter Fault
"Speaker Faulty"
163. If the
399.
Servicing Procedures
163.
161