Speaker Trouble - LG F1200 Service Manual

4. TROUBLE SHOOTING

• Speaker Trouble

Soldering status of CN400 and
Check the Resistance
Check the Resistance between
C510 and C524 (C522 and C523)
Does Sinusoidal wave
appear at R520, R534?
Does Rectagular wave appear
at C510, C524 (and C522, C523)?
START
Speakers is OK?
YES
between +/— port of
speaker (Left, Right).
Is it about 8Ohm?
YES
Is it about 9Ohm?
YES
YES
YES
Replace the
Main PCB
Resolder the
NO
CN400
or Sfpeakers
NO
Replace the
speaker
NO
The Connection between
FPCB and Main Board is OK?
YES
Replace the
FPCB
NO
Replace the
Main PCB
NO
Check the voltage
level at C519 (or C520)
ls it 33V?
YES
Replace the
U50 (or U503)
- 46 -
NO
Reconnect the
FPCB Goto 3
NO
Replace the
U508