Nokia NHM-4 Series Assembly, Disassembly And Troubleshooting Instructions page 47

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Audio troubleshooting 1
Audio
faults
Is earpiece working?
Yes
Audio
faults 2
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No
Try change earpiece.
Is it working now ?
Connect grip.
Set phone in LOCAL mode.
Use Phoenix Audio Test.
Set EXT IN, HP OUT, LOOP ON.
Measure DC
offset voltage
from Earpiece pads.
Is it ~1.38V ?
Measure
MICB2 voltage
from XMICP pads
(C105)
Is it ~2.2V ?
Earpiece
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Yes
No
No
Yes
No
Yes
1+0
Retest
Check L151, C160,
R164 and line.
If OK
–> Change UEM
Check L106, C112,
R161, C163, R166,
C165, R167 and
line.
If OK –>
change UEM.
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