TM8100 Mobile Radio
Service Manual
Diagnosis of Faults on Main Board
223
May 2004 © Tait Electronics Limited
Task 9 —
Repair Circuitry
Following the checks in Task 8, locate and repair the fault in the circuitry
as follows:
1.
Cycle the power. Enter the CCTM command
326 5
to set the
transmitter to maximum power. Enter the CCTM command
33
to place the radio in transmit mode. Measure the voltage at pin 9
of IC303 [at 3E7/3H4] in the power-control circuit (see
). The voltage should be as given in
. If it is,
go to Step 3. If it is not, go to Step 2.
2.
Check the voltage at pin 5 of IC303 [at 3J7/3H8] (or use the
FWD PWR
test point). The voltage should be as given in
.
If it is, check the components between pins 6 and 7 of IC303 (see
and
) [R340, C3090, R3090 (B1 band) or
R340, C345, R3009 (D1, H5, H6)]. If it is not, check the
components of the directional coupler (see
case repair any fault. Replace IC303 if necessary. Confirm the
removal of the fault and return to
. If the repair
failed, return to
and replace the complete main-
board assembly.
3.
Measure the voltage at pin 8 of IC303 [at 3D7/3H4] in the power-
control circuit. The voltage should be 7.4 ± 0.5 V. If it is not, go
to Step 5. If it is, measure the voltage at pin 10 of IC303. The
voltage should be 4.8 ± 0.5 V. If it is, go to Step 4. If it is not, go
to Step 5.
4.
Check C322, C324, R342, R347 (see
) and R396 (see
and
) in the power-control circuit. Repair
any fault. If these components are not faulty, replace IC303.
Confirm the removal of the fault and return to
the repair failed, return to
and replace the
complete main-board assembly.
5.
Measure the voltage at pin 1 of IC301 [at 3C8/3J3] in the power-
control circuit. The voltage should be 4.8 ± 0.5 V. If it is, check
the components R334 (see
) and C319 (see
) [at 3D8/3J4]. If it is not, check the
components between the
PWR
test point [at 3A9/3K1] and pin 1
of IC301 (see
). Repair any fault. Replace IC301 if
necessary. Confirm the removal of the fault and return to
. If the repair failed, return to
replace the complete main-board assembly.
6.
Check for short circuits at the gate of the PA driver Q306 [at
3C3/3E3]. Check R333, R336 [at 3D7/3H3] (see
),
C310, R324 and R327 [at 3C4/3F2] (see
and
) between the power-control circuit and Q306.
Repair any fault. If these components are not faulty, replace
Q306. Confirm the removal of the fault and return to
. If the repair failed, return to
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 ...