Check Itf Vol Wip Dc Input Signal - Tait TM9100 Service Manual

If the output of the voice-band CODEC is correct, but the signal level does
Task 6 —
Check
ITF VOL WIP DC
not vary as the volume control is varied, check the
Input Signal
1.
2.
3.
4.
5.
6.
7.
8.
9.
TM9100 Service Manual
© Tait Electronics Limited August 2005
Check the voltage on the
C706 (see Figure 13.3). As the volume varies, the voltage should
vary as follows.
junction of R708 and C706: 0.0 to 1.2V as volume varies
If the voltage varies as expected, go to
Step 3.
Check the control-head connector SK100. Repair or replace the
connector if necessary.
Confirm the removal of the fault and go to
page 147. If the repair failed or the fault could not be found, replace
the main-board assembly and go to
Remove the can.
CDC TOP
Check the voltage at the junction of R234 and R235
(see Figure 13.3). As the volume varies, the voltage should vary as
follows.
junction of R234 and R235: 0.0 to 0.6V as volume varies
If the voltage varies as expected, CODEC 1 (IC204) is suspect;
replace the main-board assembly and go to
page 147. If it does not, go to
Check for continuity across R234, and check that R235 is properly
soldered (see Figure 13.3). Repair any fault.
Confirm the removal of the fault and go to
page 147. If the repair failed or the fault could not be found, replace
the main-board assembly and go to
ITF VOL WIP DC
line at the junction of R708 and
VOL WIP DC
Step 5. If it does not, go to
"Final Tasks" on
"Final Tasks" on page
"Final Tasks" on
Step 8.
"Final Tasks" on
"Final Tasks" on page
CODEC and Audio Fault Finding
signal.
147.
147.
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