318
Transmitter Fault Finding (40W/50W)
TM8100/TM8200 Service Manual
© Tait Electronics Limited
June 2006
Task 34 —
Repair PIN switch
If the RF power at the PIN switch is low, the switch is not drawing the
expected current or the diode is faulty. Check the circuit as follows:
1.
Remove the
PIN
TOP
can.
2.
Perform a diode check of
D307
(VHF) or
D3507
(UHF)
(see
). If it is not faulty, go to
. If it is, replace
D307 or D3507, and go to
3.
Check the
+9
V
0_
TX
supply to the PIN switch via the following
resistors on the bottom-side of the PCB (see
and
■
VHF:
R389
and
R390
■
UHF:
R3000
,
R389
and
R390
If any resistor is faulty, replace the resistor as well as
D307
(VHF) or
D3507
(UHF). (A faulty resistor is likely to have resulted in damage
to D307 or D3507.)
4.
With the test lead still connected to the test set, enter the CCTM
command
326 5
to set the transmitter power level to the maximum.
5.
Enter the CCTM command
101
x x
0
, where
x
is the lowest
frequency (in hertz) for maximum power, as given in
(B1),
(H5) or
6.
Enter the CCTM command
33
to place the radio in transmit mode.
Again measure the RF output power. This should be:
7.
Enter the CCTM command
32
to place the radio in receive mode.
8.
Enter the CCTM command
101
x x
0
, where
x
is the highest
frequency (in hertz) for maximum power, as given in
(B1),
(H5) or
9.
Repeat
to
10.
Remove the test lead and test capacitor, and resolder the blocking
capacitors
C361
,
C362
and
C363
(see
) in position.
11.
If the power in both the above cases is now correct, the fault has been
rectified; go to
. If it is not, the repair
failed; replace the board and go to
RF output power: more than 70W VHF)
more than 60W (UHF)
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...
