LG LCD TV/DVD - I have full picture and sound with

It means you are trying to produce a picture that is the wrong size/resolution or 'format'.

Sounds like you have the wrong input selected for where you have it plugged in. Turn on the TV and the source(cable box, DVD...etc.) On the remote locate the input or the source button. Press that until you get a picture and sound.

If the TV AND the DVD player are not powering on, then it sounds like the problem is at the receptacle or power strip, where the TV and the DVD player are plugged in. Make sure the receptacle or power strip is working. Plug something else in, a lamp, a radio, anything, and see if it works. If it doesn't then the power strip is off or not working or the wall receptacle is not working.

service the logic cont card

I have the same problem. Good picture with no sound at all. I have a LG DVX583KH and LG TV LM7200. I connected the DVD player to TV via HDMI cable, I have a clear picture but no sound. I try to hook up the DVD to other TV and it works both sound and picture. Please help

connect audio output (RCA Jack white n red color) from the video, to the audio input of your TV. Make sure you use same AV channel for the video and audio.
i.e AV1 or AV2 or AV3

Look at this

LG tv flatron no sound, picture everything else is fine but no sound what can be done to fix it

HERE is the servce manual for this TV

sound board going bad.