Nokia NHM-4 Series Assembly, Disassembly And Troubleshooting Instructions page 48

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Audio troubleshooting 2
Audio
faults 2
Is microphone OK ?
Yes
Audio
faults 3
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Try change grip.
No
Is it working now ?
Set phone in LOCAL mode.
Use Phoenix Audio Test.
Set HP IN, EXT OUT, LOOP ON.
Measure MICB1
voltage from MICP
pads (C107)
Is it ~2.1V ?
Check C151,
R157 and line.
If OK –>
Change UEM,
retest..
If fail, change UPP
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Yes
No
No
Yes
Retest
Check L104
C107, C152,
R152, R153,
C168, C166,
C215 and line.
If OK –>
Change UEM
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