Microphone - Nokia RH-27 Series Technical Documentation Manual

CCS Technical Documentation

Microphone

Audio
faults,
page 2
Is the microphone
working?
YES
Audio
faults,
page 3
Issue 1 11/2003 Confidential
Change the
microphone. Is it
NO
working now?
NO
Set phone in Local Mode. Use
Phoenix "Baseband Audio
Control" and set the following:
Enable Tx, Enable Rx, Select
MIC1, Enable HF only
(differential). Talk through the
microphone.
Measure MICB1
voltage from MICP
pads on bottom
connector.
Is it ~2.1V?
YES
Is the signal going to
the UEM at MIC1P
and MIC1N at R172?
YES
Is the signal going
out of the UEM at
XEAR, pin 11, 12, 13,
and 14 on the
bottom connector
(X101)?
©2003 Nokia Corporation
Troubleshooting - Baseband
YES
Check connections
at C175 and R170. If
NO
OK, change UEM.
Check connections
at R171, R172, R170,
R173, C173, C174,
NO
C175, C170, C171,
C172. If OK, change
microphone.
Check L103, L104,
N150, C160, C161,
C169, C166, C168,
C164, C180, C181,
C183, C184, C185,
NO
C112, C113, C114,
C115, R163, R976,
R977, R165, R164,
R112, R113. If OK,
change UEM.
YES
RH-27
Retest
Retest
Page 49