LG 42PT81 Service Manual page 24

18. No Sound
(1) Symptom
1) LED is green.
2) There is a picture but no sound.
(2) Follow check
Is there sound in any
mode?
Yes
Is there no sound
only for HDMI?
Yes
Is there no
sound only AV?
Yes
Is there no sound
only for RF?
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Only for training and service purposes
No
No
Download the EDID data.
No
Is the output
of IC300(Pin52,53)
normal?
Yes
Check the signal after IC300.
refer to circuit diagram.
No
Check the Tuner In/Out.
Is the speaker
on?
Is the speaker
cable normal?
No
Replace the
IC300
Is the IC400
operating normal?
Is the IC401
operating normal?
Is the IC402
operating normal?
Replace the VSC B/D
- 24 -
No
Set speaker on
in the menu.
Yes
No
Check the Speaker
cable
Yes
No
Replace the IC400
Yes
No
Replace the IC401
Yes
No
Replace the IC402
Yes
LGE Internal Use Only