Samsung SGH-I907 Service Manual page 67

10-4. MIC Working
Operate Microwave
3,4Pin in
IFC400 Signal
ON?
Yes
Check the DC bias voltage on MIC path
Yes
The voltage of
R418 is about
1.6V ?
YES
AE17, AE18 in
UCP200 Signal
ON ?
YES
END
No
Change Earphone
No
Check the path around MIC Bais circuit
No
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3.5Pin in
HDC400
Signal ON?
Yes
Check the C405, C406, UCD402
10-15
Flow Chart of Troubleshooting
No
Change
MIC Assy's