Nokia NHL-10 Baseband Troubleshooting And Manual Tuning Manual page 28

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