278
Transmitter Fault Finding (40W/50W)
TM8100/TM8200 Service Manual
© Tait Electronics Limited
June 2006
Task 10 —
Repair Output
Matching Circuitry
If the checks in
show that the power and current are still skewed,
there is a fault in the output matching circuitry.
1.
If not already done, remove the
PAF
TOP
can.
2.
Check for faulty, shorted or misplaced components in the circuit
between the test capacitor and the common drain of
Q309
and
Q310
(see
). Repair any fault.
3.
Program the radio with the highest frequency in the radio’s frequency
band: Enter the CCTM command
101
x
x
0
, where
x
is the frequency
in hertz. The required values for the different frequency bands are
given in
4.
Enter the CCTM command
33
to place the radio in transmit mode.
5.
Note the RF output power measured by the test set, and note the
current reading on the DC power supply.
6.
Enter the CCTM command
32
to place the radio in receive mode.
7.
Program the radio with the centre frequency in the band: Enter the
CCTM command
101
x
x
0
, where
x
is the frequency in hertz.
8.
Repeat
to
9.
Program the radio with the lowest frequency in the band: Enter the
CCTM command
101
x
x
0
, where
x
is the frequency in hertz.
10.
Repeat
to
11.
Remove the test lead and test capacitor, and resolder the coupling
capacitors
C348
,
C349
and
C350
in position (see
12.
If the power and current are now correct at all three frequencies, the
fault has been rectified; go to
. If they are
not, go to
.
RF output power: > 70W (VHF), > 60W (UHF)
current: < 15A (VHF), < 12A (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...
