212
Diagnosis of Faults on Main Board
TM8100 Mobile Radio
Service Manual
May 2004 © Tait Electronics Limited
Task 4 —
Check for Inhibiting
of Transmitter
If the transmitter is drawing no current or the wrong current, check
whether it is being inhibited.
1.
With the radio in transmit mode, check the logic signal at the
TX INH
test point [at 3J0/3A8] (see
). The signal is
active high. The required status is inactive — about 0 V. If it is,
go to Task 5. If the signal is active — about 1.1 V — go to Step 2.
2.
Check the logic signal at the
D TX INH
test point [at 3L0/3B9] (see
). The signal is active low. The required status is
inactive — about 3.2 V. If it is, go to Step 3. If the signal is active
— about 0 V — go to Step 5.
3.
The lock status is possibily no longer normal. With the
transmitter in transmit mode, enter the CCTM command
72
to
check the lock status. The normal status is
110
. If it is not,
proceed to the relevant subsection. If it is, go to Step 4.
4.
Check for short circuits on the
DIG
TX
INH
line from the
D TX INH
test
point. Repair any fault, confirm the removal of the fault, and
return to
. If the repair failed or no fault could be
found, return to
and replace the complete main-
board assembly.
5.
Suspect the temperature sensor. Enter the CCTM command
47
to check the temperature reading. Of the two numbers returned,
the first should be in the range
380
to
420
, corresponding to a
temperature of around 25°C. If it is, go to Task 5. If it is not (the
value will be typically less than 200), go to Step 6.
6.
If not already done, remove the
PAF
TOP
can.
7.
Check D301 and the surrounding components (see
and
). If there is no fault, go to
on the
CODEC and audio circuitry. If a fault is found, repair it, confirm
the removal of the fault, and return to
. If the repair
failed, return to
and replace the complete main-
board assembly.
Содержание TM8000 Series
Страница 32: ...32 Introduction TM8100 Mobile Radio Service Manual May 2004 Tait Electronics Limited ...
Страница 78: ...78 Circuit Descriptions TM8100 Mobile Radio Service Manual May 2004 Tait Electronics Limited ...
Страница 106: ...106 General Information TM8100 Mobile Radio Service Manual May 2004 Tait Electronics Limited ...
Страница 124: ...124 Servicing Procedure TM8100 Mobile Radio Service Manual May 2004 Tait Electronics Limited ...
Страница 164: ...164 Servicing of Control Head TM8100 Mobile Radio Service Manual May 2004 Tait Electronics Limited ...
