166
Power Supply Fault Finding
TM8100/TM8200 Service Manual
© Tait Electronics Limited
June 2006
Task 2 —
Check 3.3V Supply
If the inputs at pin 5 and pin 7 of IC602 in the SMPS circuitry are correct,
but the radio fails to power up, then the 3.3V DC supply needs to be
investigated.
1.
First determine as follows if a fault on the digital board is affecting the
supply or preventing the radio from powering up: While keeping the
ON
/
OFF
key depressed, measure the supply at the
3
V
3
test point
near
the corner of the digital board (see
). The voltage is 3.3V
when there is no fault.
If the voltage is correct, the digital board is faulty; replace the board
and go to
. If the voltage is not correct, go
Figure 7.2
Important components of the power-supply circuitry (top side),
including 9V regulator IC601
3V3 test point
Q600
LK8 (R786)
LK7 (R787)
3V3 test point: 3.3
±
0.1 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...