how can i fix my panasonic viera th-42px80b?

i woke the other morning to find i dont have a picture on my tv. i tried various devices to see if it was any of them but no such luck. i have tried using every input port but nothing is coming through. the only one with some success is from the front av ports, when i try connecting through them i get sound but still no picture, about 1, 6th of the screen from the right hand side is snowy and the message regarding dvb still shows also the volume controll and the input station id shows in the top left. i have taken the tv apart to look at the input board but cant see any visiable faults with any of the components. i dont have a meter of any kind so i cant be 100% sure that is not the fault. does anyone have any suggestions.