I've had my Sony Bravia KLV-40U100M for about a year. But the on and off problem started months ago. I thought at first it was something to do with the cable signal, but now that I've started looking on the web, it seems this TV HAS THIS PROBLEM. When the tech was out before, he said they could change some board in it and it would help. Fortunately, I have an extended warranty. I'll be calling them tomorrow--10/30--and I hope I get satisfaction. I have a 32" Sony Bravia KDL series in my bedroom that has NEVER had this problem.
Stay tuned. I paid an f-load for these TVs, and it's very distressing to hear that this may be some sort of lemon/unfixable situation. I am going to do my best not to let Sony get away with this. I'm pretty shocked, because they have always been the best.