NSB-9
Troubleshooting Instructions
CCS Technical Documentation
Page 68
Nokia Corporation
Issue 1 04/03
Audio
faults 4
Is internal
microphone
working ?
Try to change
microphone. Is it
working now?
Retest
Audio
faults 5
Yes
Yes
No
No
Set phone in LOCAL mode. Use Phoenix
“Audio Routing and Test Signals” Test. Set
routing HP in Ext out
Measure sine signal
from HSEAR and
HSEAR R lines. Is it
~160mVpp with
headset?
Check R154, C150
and line. If OK ->
change UEM
Yes
No
Check microphone
connector. Is it OK
Change defect part and
retest
No
No
Measure MICB1 voltage
from MICP (J107). Is it
~2.1V ?
Check L110, C153,
R155, C154 and
line. If OK -> change
UEM
Retest
Yes
Yes
No
Connect external 1kHz (sine 30mVpp)
audio signal in MICP line and ground line
to MICN line
(3
3) If you don’t get such a small signal out from signal generator, use resistor network to attenuate
signal