TM8100/TM8200 Service Manual
Power Supply Fault Finding
167
© Tait Electronics Limited
June 2006
2.
Disconnect the 13.8V supply at the power connector. Remove
R199
(see
). Reconnect the 13.8V supply.
3.
With the probe of the multimeter on the
3
V
3
test point
, press the
ON
/
OFF
key. If the voltage is now 3.3 ± 0.1V, the digital board is faulty;
replace the board and go to
. If the voltage
is still not correct, go to
4.
If the digital board is functional, the fault is on the main board.
Replace
R199
. Disconnect the 13.8V supply. Use the multimeter to
measure the resistance between the
3
V
3
test point
and ground.
If there is a short circuit, continue with
. If there is no short
circuit (but the voltage is wrong), go to
.
5.
Search for shorts to ground in the components
C603
,
C612
,
C613
,
C618
,
D606
of the SMPS circuitry (see
) as well as in the
CODEC and interface circuitry. Repair any fault and repeat the
resistance measurement of
to confirm the removal of the fault.
If there is no fault, go to
. If the fault remains, the repair failed;
replace the board and go to
.
6.
Reconnect the 13.8V supply. Press the
ON
/
OFF
key. If the radio powers
up, return to
. If the radio fails to power
up, disconnect the 13.8V supply and go to
7.
Measure the resistance of
L601
(see
). The resistance
should be virtually zero. If it is, go to
. If it is not, replace L601.
Reconnect the 13.8V supply and press the
ON
/
OFF
key. If the radio
powers up, return to
. If the radio fails to
power up, disconnect the 13.8V supply and go to
8.
Remove the
CDC BOT
can. Remove
IC603
(3.0V regulator) and
IC604
(2.5V regulator) (see
). Reconnect the 13.8V
supply and press the
ON
/
OFF
key. If the 3.3V supply is restored, go to
to check each regulator (3.0V and 2.5V) in turn. If the 3.3V
supply is not restored, continue with
.
9.
Suspect
IC602
. Disconnect the 13.8V supply. Replace IC602 with a
spare (see
). Resolder
IC603
and
IC604
in position
(see
). Reconnect the 13.8V supply and press the
ON
/
OFF
key. If the radio powers up, return to
If the radio fails to power up, the repair failed; replace the board and
go to
.
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...
