388
CODEC and Audio Fault Finding
TM8100/TM8200 Service Manual
© Tait Electronics Limited
June 2006
Task 6 —
Check
ITF
VOL
WIP
DC
Input Signal
If the output of the voice-band CODEC is correct, but the signal level does
not vary as the volume control is varied, check the
ITF
VOL
WIP
DC
signal.
1.
Check the voltage on the
VOL
WIP
DC
line at the junction of
R708
and
C706
(see
). As the volume varies, the voltage should
vary as follows.
2.
If the voltage varies as expected, go to
3.
Check the control-head connector
SK100
. Repair or replace the
connector if necessary.
4.
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
5.
Remove the
CDC
TOP
can.
6.
Check the voltage at the junction of
R234
and
R235
(see
). As the volume varies, the voltage should vary as
follows.
7.
If the voltage varies as expected, CODEC 1 (
IC204
) is suspect;
replace the board and go to
. If it does not,
8.
Check for continuity across
R234
, and check that
R235
is properly
soldered (see
). Repair any fault.
9.
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
junction of R708 and C706: 0.0 to 1.2V as volume varies
junction of R234 and R235: 0.0 to 0.6V as volume varies
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...