Picture is dark and audio sounds strange.
The screen can become dim and the sound can go on and off while watching TV.
Things to check
① Do you have the remote control(magic/general) that was given by LG when you purchased the TV?
② Do you see Mute UI(magic) or Mute button(general) on the remote control? (In the middle of remote control)<span style="font-family: Arial; font-size: 12pt;"> </span>
How to fix
AV might be adjusted so the screen can become dim and the sound might go on and off.
In a simple way, you can reset AV, then it will be initialized as if it is fresh from factory.
(Applied to LM6000 and higher_L9/MKT_S,W Ver:4.04.05 and higher)
① Push Mute button of magic/general remote control three consecutive times.
② If “Yes/No” window pops up, select yes by pushing OK button of remote control.
③ Audio/Video will be initialized.
(ex. Audio/Video: Standard, Power Saving Mode: Off) etc..