I have seen some stereo systems in cars that hit like 160 with subwoofers and thats what im going for it just didnt seem like 120 would be as loud as you guys are saying. I don't understand how the decibel system works all to well.
You could very easily have bad internal connections. I would make sure that everything is secured into there plugs and try turning it on again. if it doesn't work then you should contact lg and ask them why it might be doing this.
Could you link a picture? that might help me out a little more. but The multi-strand ribbon cables for the x-y scans could have some poor connections. The heat at the back of the screen over time has a lot to do with it. Sometimes, inserting a piece of cardboard to press down the ribbon cables...