Nokia RH-30 Series Troubleshooting Instructions page 53

Figure 18: Audio troubleshooting (2)
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Earpiece
2
Connect EXT audio
signal 1kHz (sine,
200mVpp) between
XMICP and XMICN
pads (X101, 9/10)
Measure sine
Measure sine
signal from earpiece
Check C154. If OK
No signal to UEM (R155). Yes
pads (J310,J311).
change UEM
Is it ~130mVpp ?
Is It ~880mVpp ?
Yes
No
Check C154, R155,
C156, R154, C159,
R158, R159 and lines.
Change UPP
Retest