Whenever I connect a composite source to my TV - Pana TX28PS1 - especially games consoles, the image is unstable and repeatedly jumps up and down on the screen. If I turn on the console, and go to manual tuning of the tv and re-tune the channel, the image stops jumping. If I then switch off the console and back on again the jumping starts up. It is as if the TV isn't 'locking' onto the signal source for some reason. Sometimes it does it on the S-video input - but never the scart. I am guessing that perhaps the circuitry that comes before the scart input for composite and s-video might be faulty? Any ideas?