Nokia NSB-9 Service Manual page 243

CCS Technical Documentation
Audio
faults 5
Is external
microphone
working ?
Yes
END
4) If not working set "Loops Off" and after that "Ext in HP out" again
Issue 1 04/03
No
Check if external
audio device is OK?
Yes
Check system
connector X102. Is
it OK ?
Yes
Set phone in LOCAL mode. Use Phoenix
"Audio Routing and Test Signals" Test. Set
routing Ext in HP out
Yes
Measure MICB2 voltage
from XMICP (X102 / pin
10). Is it ~2.0V with
headset?
Yes
Connect external 1kHz (sine 200mVpp)
audio signal in XMICP line and ground line
to XMICN line.
Measure sine signal
from EARP and EARN
lines. Is it ~190mVpp?
Yes
Retest
Nokia Corporation
Troubleshooting Instructions
No
undamaged ext. audio
No
Change defect part and
(4
No
Check L103, R161, C163,
C162, R157, C158 and line. If
OK -> change UEM
Check C159 If OK, change
Measure signal
No
from C152. Is it
Check L103, R161, C163, C162, R156,
R157, C158, C152, C159 and also
corresponding componenets from
XMICN line line. Change defect part.
NSB-9
Retest with
device.
retest
UEM
Yes
~110mVpp?
No
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