I used to have a Sony STRDB830 and I sold it to a friend of mine a while ago. He has only just had a chance to use it because he didn't have a suitable stand and he tells me that every time he plugs it in 'protection' flashes up on the display. I told him to make sure the leads were all ok and that the speaker wire wasn't touching and he said he has unplugged all the cables and as soon as he switches it on the protection (or whatever it says) comes up on the display. The only other thing I could think of is that it may be overheating but apparently this isn't the case. Does anyone else know of anything he can do to sort this out? He's also tried re-setting it to the factory settings. Any advice would be much appreciated as it was in perfect condition when I sold it and I don't understand what's wrong with it now.