NHL-10
CCS Technical Documentation
Baseband Troubleshooting
28
COMPANY CONFIDENTIAL
ISSUE 2 01/2004
Copyright © 2003 Nokia. All Rights Reserved.
Figure 21: External MIC troubleshooting
START
Check system connector and PWB
contacts. Are they OK?
Clean contacts / replace system
connector, X381
Set Phone Audio Routing from MIC2
(Ext. XMIC) to know n w orking audio
output (i.e. EAR [HP] or HF/HFCM
[Ext]). Ensure MIC Bias (MICB2) is
ON.
Is MIC Bias 2.1V non
present at R343 or at
the system connector?
Check R343, R347 and
other passive components
in MIC Bias path.
Is MIC Bias 2.1V non
present at R343 or at
the system connector?
Change UEM
Are the audio signals to
UEM OK?
Check audio path through
C345, C346 and associated
passives. Also check the
Hookint route through R361.
Check for shorts / low
impedance to GND & opens in
series components. Change
passives w here necessary.
Are the audio signals to
UEM OK?
Change UEM
Does the audio w ork in
a call?
Change UPP_
WD2
END
No
Yes
No
Yes
No
Yes
No
No
No
Yes
Yes
Yes
Connect a know n w orking 4
terminal DCT4 headset to the
system connector.
Audio Troubleshooting
External MIC
