We have a Sony KDF-E50A10. Several months ago, it would randomly go off (screen would go black, but we would still have sound). Repariman came out (it was still under warranty), but couldn't find a problem. A few weeks ago it did it again. And now, when we go to turn it on, it wont come on for 8-10 minutes. Doesn't matter if we unplug it or not, it still wont turn on for that long. Any ideas?