LG W3000 Service Manual page 70

Earphone receiving
2
path problem
Is the signal level at
R334 a few tens or hundreds
VAC?
Yes
Resolder R334 and J301.
4
Earphone sending
3
path problem
Voltage at pin 3 of
U304 = 1.5~1.9VDC?
Yes
Is the signal level
across C145 a few tens or
hundreds VAC?
Yes
Resolder C170.
Does it work well?
Yes
No
Is the signal level at pin
6 of U305 a few tens or
hundreds VAC?
Yes
Yes
No
Is the signal level at pin
6 of U308 a few tens or
hundreds VAC?
Yes
Resolder C145.
No
Re-download software.
Does it work well?
Yes
4
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4. TROUBLE SHOOTING
No
Is the signal level at pin
5 of U305 a few tens or
hundreds VAC?
Yes
Resolder or replace U305.
Re-download software.
Does it work well?
Change the main board.
No Is the signal level at
pin 5 of U308 a few tens or
hundreds VAC?
Yes
Resolder or replace U308.
No
Change the main board.
No
No
No