Nokia 8310 Repair Hints page 10

Customer Care Europe & Africa
SCCE Training Group
© 2002 Nokia Mobile Phones
CHAPTER 5 AUDIO-FAULTS
In case of any audiofault in the phone, the best way to define the fault is to make a call with the defect phone to a proper
working one. In case that you can hear the speech of the proper working phone in the defect one but the other way round the
speech of the defect phone is not audible in the proper working phone you know that the internal microphones signalpath is
responsible for the fault.
Of course you can use the same procedure to check the external audiopathes XMIC and XEAR.
internal audio
does not work
int. micro faulty
change microphone,
retest phone
nOK
check MicBias
2.1VDC
nOK
at R152 on active
micro
OK
check MIC1N/P for shorts to GND
and interruption, especially check
C151! Probably D200 faulty
I009 bottomconnector
- check mechanical appearance of bottomconnector I009 in case that internal microphone does not work, external audiopath
seems to be interrupted or headset is not recognized. Retest phone with new connector in case of doubt.
Also ensure that contact pads for connector on PCB are clean.
I005 speaker
check mechanical appearance of speaker. Change part if spring contacts are bent or soiled. Resistance of speaker normally
-
is 30Ω. Also ensure that contact pads on PCB are clean.
C151/C155
- check resistance of the double capacitors, which normally is > 20MΩ. Both parts have tendencies to leak and often are
responsible for missing uplink audio (C151 in case of internal -, C155 in case of external audio faults).
D200
- due to the missing possibility of rewriting IMEI and Simlock data after changing UEM D200 it is not useful to change
this part at the moment.
© NMP 2002
Audio-Faults
int. speaker faulty
change speaker,
retest phone
nOK
check speaker lines for shorts
to GND and interruption.
Probably D200 faulty
check/change R152,
C166/168.
Probably D200 faulty
CONFIDENTIAL
NHM-7
Date 28.02.2002
external audio
does not work
ext. speaker faulty
change headset/
bottomconnector,
retest phone
nOK
check XEAR-lines for shorts to
GND and interruption.
Probably D200 faulty
check/change R166, C165.
Probably D200 faulty
Checked by:
SCCE Training Group
10 (18)
Repairhints
Version 1.0 Approved
ext. micro faulty
change headset/
bottomconnector,
retest phone
nOK
check MicBias
2.7VDC
nOK
at R166 on active
micro
OK
check XMIC-lines for shorts to
GND and interruption, especially
check C155! Probably D200 faulty
Approved by:
SCCE