164
Power Supply Fault Finding
TM8100/TM8200 Service Manual
© Tait Electronics Limited
June 2006
Task 1 —
Check Inputs to
SMPS
The test equipment and radio should be set up as described in
. If not already done, remove the board.
Connect the control head to the assembly. Then check the SMPS as follows:
1.
Use a multimeter to check the supply voltage at pin 7 of
IC602
(see
) in the SMPS circuitry; the voltage should be:
If it is, go to
. If it is not, go to
.
2.
Disconnect the 13.8V supply at the power connector PL100. Check
for continuity and shorts to ground in the path between the power
connector
PL100
and pin 7 of
IC602
(see
). Locate and
repair the fault.
3.
Reconnect the 13.8V supply. Confirm the removal of the fault by
measuring the voltage at pin 7 of
IC602
. If the voltage is correct,
continue with
. If it is not, the repair failed; replace the board
and go to
.
4.
Press the
ON
/
OFF
key. If the radio powers up, return to
5.
Check the digital power-up signal at pin 5 of
IC602
(see
); the signal is active high, namely, when the voltage
exceeds 2.0V DC. Measure the voltage at pin 5.
If it exceeds 2.0V, go to
. If it does not, go to
.
6.
Keep the probe of the multimeter on pin 5 of
IC602
and press the
ON
/
OFF
key. The voltage should exceed 2.0V DC while the key is
depressed. If it does, go to
. If it does not, go to
7.
Disconnect the 13.8V supply at the power connector PL100. Check
for continuity and shorts to ground in the path from pin 5 of
IC602
,
via
R600
and via
Q709
in the interface circuitry (see
pin 9 of the control-head connector
SK100
(
ITF PSU ON OFF
line).
Locate and repair the fault. Go to
8.
Reconnect the 13.8V supply. Press the
ON
/
OFF
key. If the radio powers
up, return to
. If it does not, go to
9.
With the probe of the multimeter on pin 5 of
IC602
(see
press the
ON
/
OFF
key again. The voltage should exceed 2.0V DC
while the key is depressed. If it does, go to
. If it does not, the
repair failed; replace the board and go to
pin 7 of IC602: 13.8 V DC
pin 5 of IC602: more than 2.0 V DC
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...
