Thanks for the update!

Thanks for the quick reply i found the problem it was a bad A/V cable and S/video cable thanks again

Depends on what you feed the input to set with, if on an antenna and it only does this on the antenna, then a varying signal strength level can do this, however if on an AV input then it could possibly indicate a faulty quartz crystal or chip, but its quite impossible to give an assessment on whether or not its worth repairing, as although the component cost is so to speak "peanuts", it depends on how long someone takes to find the offending component.