My dads beloved Samsung plasma started powering on and off every few minutes last night, I said to sit off at mains but it still continued afterwards. When he tried it again this morning it was fine for around 3 hrs. This happened about 6 weeks ago to but shutting off at the mains cured it. It's still under warranty but I haven't called it in yet as intermittent issues can be hard to find. Any ideas please ?. Thanks.