Check 2.3V Supply; Check Bias Network - Tait TM9100 Service Manual

If the
Task 13 —

Check 2.3V Supply

checked.
1.
2.
3.
4.
5.
If the signal at the
Task 14 —

Check Bias Network

above tasks reveal no fault, check the bias network.
1.
2.
3.
4.
5.
6.
392 CODEC and Audio Fault Finding
signal is not as expected, the 2.3V supply needs to be
CH MIC AUD
If not already done, remove the
Check the voltage across C202 (see
voltage across C202: 3V
If the above voltage is correct, go to
Check the soldering of R209, and check for shorts to ground at C202
(see Figure 13.9). 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
503 test point is incorrect, but the other checks in the
TP
Remove the can.
CDC TOP
Check the voltage at the junction of R229 and R232
(see Figure 13.10):
junction of R229 and R232: 1.5V DC
If the voltage is correct, go to
CODEC 1 (IC204) is faulty; replace the main-board assembly and go
to "Final Tasks" on page
Check the soldering of R229 and R232, and check for shorts across
R232 (see Figure 13.10). 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
can.
CDC BOT
Figure 13.9):
Task 14. If it is not, go to
"Final Tasks" on
"Final Tasks" on page
Step 4. If it is not, go to
147.
"Final Tasks" on
"Final Tasks" on page
© Tait Electronics Limited August 2005
Step 4.
147.
Step 5.
147.
TM9100 Service Manual