Tx Audio Error - Motorola APX 3000 Detailed Service Manual

5-24
5.7 TX Audio Error – External Mic Failure
Yes
Replace Backit Flex.

TX Audio error

External MIC
Is Connector
Yes
Replace Connector
Demaged or Soldered
improperly
No
Measure Audio at CODEC
C6404 Capacitor
Yes
Audio signal present?
No
Measure MIC Bias at
R6404
No
4.5 < V < 4.9
Check TX_DA thru R2817.
If no signal check CODEC
circuitry.
Inspect MIC Bias
circuit U6402 and
Supporting Circuitry
Troubleshooting Charts: TX Audio Error
View SSI Signals at R2807
and R2808 using
Oscilloscope.
Yes
No
Is SSI Audio
Data Present
Yes
Parts Solder and
Placement Correct?
No
Replace parts
Check CODEC
or OMAP
Replace U6402