Motorola APX 7000 Detailed Service Manual page 133

Troubleshooting Charts: VOCON TX Audio Error
VOCON TX Audio Error – Side Mic Failure
Backside Side Mic is
Inoperative
Isolate Problem,
Replace Backside
Mic
Is Backside Mic
Functional
No
Replace RF Board
Is Backside Mic
Functional
No
Measure Mic Bias
at R6403
4.5 < V <4.9?
Yes
Inspect SSI Audio
Data using
Oscilloscope at
R3016
Yes
Replace Backside
Mic
Yes
Replace RF Board
Inspect Mic Bias
No
Circuit U6402 and
Supporting
Circuitry
Yes
Is SSI Audio
Data Present
No
Replace VoCon
Board
Synopsis
This failure specifically refers to the
backside microphone but this flow chart
can be used to diagnose front side, and
external mics. All mics mentioned above
have similar paths and have very limited
differences. Please refer to schematic
and theory of operation section for
differences.
Replace or Repair
Parts
No
Are Parts Solder
Yes
Connections and
Placement Correct
View SSI Signals
at R1017, R1007,
and R1008 Using Is SSI RF Data
an Oscilloscope
Replace VoCon
Repair or Replace
Connector
Is Connector
No
Replace VoCon Damaged or
Board
Improperly
Yes
Connector J1001
Present
No
Board
5-29
Yes
Soldered
Examine