400
CODEC and Audio Fault Finding
TM8100/TM8200 Service Manual
© Tait Electronics Limited
June 2006
Task 13 —
Check 2.3V Supply
If the
CH
MIC
AUD
signal is not as expected, the 2.3V supply needs to be
checked.
1.
If not already done, remove the
CDC
BOT
can.
2.
Check the voltage across
C202
(see
3.
If the above voltage is correct, go to
. If it is not, go to
4.
Check the soldering of
R209
, and check for shorts to ground at
C202
(see
). Repair any fault.
5.
Confirm the removal of the fault and go to
. If the repair failed or the fault could not be found, replace
the board and go to
Task 14 —
Check Bias Network
If the signal at the
TP
503
test point is incorrect, but the other checks in the
above tasks reveal no fault, check the bias network.
1.
Remove the
CDC
TOP
can.
2.
Check the voltage at the junction of
R229
and
R232
(see
):
3.
If the voltage is correct, go to
.
4.
CODEC 1 (
IC204
) is faulty; replace the board and go to
.
5.
Check the soldering of
R229
and
R232
, and check for shorts across
R232 (see
). Repair any fault.
6.
Confirm the removal of the fault and go to
. If the repair failed or the fault could not be found, replace
the board and go to
voltage across C202: 3V
junction of R229 and R232: 1.5V 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...