TM8100/TM8200 Service Manual
Transmitter Fault Finding (25W)
357
© Tait Electronics Limited
June 2006
Task 22 —
Directional Coupler
and Buffer
Amplifier
Following the checks in
, 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 buffer amplifier will be located.
1.
Cycle the power.
2.
Enter the CCTM command
326 5
to set the transmitter to maximum
power.
3.
Enter the CCTM command
33
to place the radio in transmit mode.
4.
Measure the voltage at pin 9 of
IC303
in the power-control circuit
(see
5.
The above voltage should be as given in
. If it is, go to
6.
Check the voltage at pin 5 of
IC303
(or use the
FWD PWR
test point
)
(see
). Note that the probe impedance might affect the
measurement.
7.
Enter the CCTM command
32
to place the radio in receive mode.
8.
The voltage measured in
should be as given in
.
If it is not, go to
. If it is, go to
Table 12.7
Voltages at IC303 at maximum power (40 W)
Frequency band
Frequency (MHz)
Voltage (V)
Pin 9
Pin 5 (
FWD
PWR
)
A4
66
77
88
1.3 ± 0.5
1.5 ± 0.5
1.7 ± 0.5
1.1 ± 0.5
1.3 ± 0.5
1.4 ± 0.5
B1
136
155
174
2.2 ± 0.5
2.3 ± 0.5
2.5 ± 0.5
1.9 ± 0.5
2.1 ± 0.5
2.3 ± 0.5
C0
174
199.5
225
1.6 ± 0.5
1.8 ± 0.5
1.9 ± 0.5
3.0 ± 0.5
3.4 ± 0.5
3.7 ± 0.5
D1
216
241
266
2.2 ± 0.5
2.2 ± 0.5
2.3 ± 0.5
4.3 ± 0.5
4.3 ± 0.5
4.7 ± 0.5
H5
400
435
470
3.4 ± 0.5
3.8 ± 0.5
4.0 ± 0.5
3.3 ± 0.5
3.7 ± 0.5
3.9 ± 0.5
H6
450
490
530
3.9 ± 0.5
4.2 ± 0.5
4.7 ± 0.5
3.8 ± 0.5
4.1 ± 0.5
4.6 ± 0.5
Summary of Contents for TM8235
Page 1: ...TM8100 mobiles TM8200 mobiles Service Manual MMA 00005 04 Issue 4 June 2006...
Page 10: ...10 TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 62: ...62 Description TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 148: ...148 Disassembly and Reassembly TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 162: ...162 Servicing Procedures TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 178: ...178 Interface Fault Finding TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 258: ...258 Receiver Fault Finding TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 446: ...446 Spare Parts TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
