Audio Troubleshooting (External Mic To External Out) - Motorola MTH500 Service Manual

Audio Troubleshooting (External Mic to External Out)

Set the audio input to the external mic to 1.02KHz @ 44mV RMS. Test sequence is controlled by TetraCom commands to
the external mic-to-external out loopback.
Check R108, C104 &
continuity to connec-
tor.
Tetracom Routine
MIC VA
MICGA 0
DSP_LOOP ON
DSP_VOL 0
Vol 0
SPKR VA
68P02963C70-O
Connect a scope or DVM to the following points
and measure ac levels in Vrms.
Check R110, C103 &
continuity to connec-
tor.
Start AUDIO_LOOPBACK (1)
Is voltage at
No
C103 =
44mVRMS?
Yes
Is voltage at
No
C104=
66mVRMS?
Yes
No trouble found
Troubleshooting
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