TM9100 Service Manual
Transmitter Fault Finding (50W/40W Radios)
287
© Tait Electronics Limited
August 2005
Task 22 —
Directional Coupler
and Buffer
Amplifiers
Following the checks in
Task 19
to
Task 21
, locate the fault and repair the
circuitry as described in the remaining tasks of the section. In this task any
faults in the directional coupler or the buffer amplifiers will be located.
1.
Cycle the power.
2.
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.
3.
Measure the voltage at pin 9 of IC303 in the power-control circuit
(see
Figure 11.11
and
Figure 11.12
).
4.
The above voltage should be as given in
Table 11.7
. If it is, go to
Task 24
. If it is not, go to
Step 5
.
5.
Check the voltage at the
FWD PWR
test point
(pin 5 of IC303) and at
the
REV PWR
test point
(pin 3 of IC303) (see
Figure 11.11
and
Figure 11.12
). Note that the probe impedance might affect these
measurements.
6.
Enter the CCTM command
32
to place the radio in receive mode.
7.
The voltages measured in
Step 5
should be as given in
Table 11.7
.
If they are, go to
Step 10
. If the
FWD PWR
voltage is incorrect, go to
Step 8
. If the
REV PWR
voltage is incorrect, go to
Step 9
.
8.
Remove the
DIRC
TOP
can. Check the components of the directional
coupler (see
Figure 11.17
) and go to
Step 11
.
9.
Remove the
DIRC
TOP
can. Check D305 and R3035 (B1) or R383
(H5, H7) (see
Figure 11.17
). If there is no fault, the PIN switch or
LPF or both are suspect; go to
Task 33
. If there is a fault, go to
Step 11
.
10.
In the buffer amplifiers, check R340 and R341 (see
Figure 11.11
,
Figure 11.18
and
Figure 11.19
).
Table 11.7
Voltages at IC303 at maximum power (70 W for B1 band, and 60W for H5 and H7)
Frequency band
Frequency (MHz)
Voltage (V)
Pin 9
Pin 3 (
REV
PWR
)
Pin 5 (
FWD
PWR
)
B1
136
155
174
2.6 ± 0.5
2.9 ± 0.5
3.2 ± 0.5
0.4 ± 0.3
0.4 ± 0.3
0.5 ± 0.3
3.1 ± 0.5
3.4 ± 0.5
3.9 ± 0.5
H5
400
435
470
2.8 ± 0.5
3.0 ± 0.5
3.3 ± 0.5
0.6 ± 0.4
0.6 ± 0.4
0.5 ± 0.4
3.3 ± 0.5
3.7 ± 0.5
3.9 ± 0.5
H7
450
485
520
3.9 ± 0.5
4.1 ± 0.5
4.4 ± 0.5
0.6 ± 0.4
0.8 ± 0.4
0.8 ± 0.4
4.4 ± 0.5
4.6 ± 0.5
5.0 ± 0.5
Summary of Contents for TM9100
Page 1: ...TM9100 mobiles Service Manual MMA 00017 01 Issue 1 August 2005 ...
Page 4: ...4 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 10: ...10 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 22: ...22 Introduction TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 62: ...62 Description TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 96: ...96 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 138: ...138 Disassembly and Reassembly TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 152: ...152 Servicing Procedures TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 168: ...168 Interface Fault Finding TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 244: ...244 Receiver Fault Finding TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 396: ...396 CODEC and Audio Fault Finding TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 420: ...420 Fault Finding of Control Head TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 426: ...426 Spare Parts TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 430: ...430 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 444: ...444 TMAA04 05 Ignition Sense Kit TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 448: ...448 TMAA10 01 Desktop Microphone TM9100 Service Manual Tait Electronics Limited August 2005 ...
