Samsung SGH-600 Service Manual page 30

Troubleshooting
MICROPHONE PART
Microphone does not work
Check the connection
from MIC to J1001 (Ear-jack)
U307 pin 5 (AVCC)
the 13MHz clock signal on
U405 pin 64?
Check connection
from U405 pin 26, 27 to
MIC+ and MIC-?
Check connection
from U405 pin 21, 22 to
MIC+ and MIC-?
5-10
No
3.0V?
Yes
Is there
No
Yes
No
Yes
No
Yes
END
Resolder the connection
from Mic to J1001 (Ear-jack)
Check the circuit related to U307
Check the connection from
U408 pin 85 to U405 pin 64
Resolder the R413, R417, R419,
R420, C430, C407 and C922
Resolder the C406, C429,
C426 and C425
Samsung Electronics