274
Transmitter Fault Finding (40W/50W)
TM8100/TM8200 Service Manual
© Tait Electronics Limited
June 2006
Task 7 —
Check for Inhibiting
of Transmitter
If the transmitter is drawing no current or the wrong current, check
whether it is being inhibited. This check is also required if a
CO3
error
occurs in
1.
If not already done, enter the CCTM command
33
to place the radio
in transmit mode.
2.
Check the logic signal at the
TX INH
test point
(see
The signal should be:
3.
If the signal is inactive as required, go to
. If it is active — about
1.1V — the transmitter is being inhibited; go to
4.
Enter the CCTM command
32
to place the radio in receive mode,
and go to
in
“Biasing of PA Driver and PAs” on page 280
5.
Check the logic signal at the
D TX INH
test point
; see
(VHF) or
(UHF). The signal should be:
6.
If the signal is inactive as required, go to
. If it is active — about
3.2V — the temperature sensor is suspect; go to
.
7.
Enter the CCTM command
32
to place the radio in receive mode,
and go to
8.
The lock status is possibly no longer normal. Enter the CCTM
command
72
and check the lock status.
9.
Enter the CCTM command
32
to place the radio in receive mode.
10.
The normal lock status is
110
. If it is not, proceed to the relevant
.
11.
Check for short circuits on the
DIG
TX
INH
line from the
D TX INH
test
point
.
12.
Repair any fault, confirm the removal of the fault, and go to
. If the repair failed or no fault could be found,
replace the board and go to
TX INH test point: about 0V (inactive)
D TX INH test point: about 0V (inactive)
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...
