I have a KDL-52W5500 and have had the same problem. After browsing the internet it seems to not be unusual with various models of Sony TV. Might be some general build quality problem of the "digital board" as others have referred to. I've been having the clock showing with my analogue channels, but that always lost its' setting when the TV restarted. Sometimes the TV restarted while I was not watching and I could see that on the clock.
It was nothing I could ever prove to Sony or the retailer as it was only occasional. Just after the warranty ended the digital part of the TV died and I don't have picture. The clock (I was using on the analogue screen) is also not saved anymore.
I've also seen 10 blinks on the power LED, but the retailer have never answered me on what that means. The TV states I'm supposed to ask the retailer.
So, try to somehow get it fixed ASAP before the warranty end or you and up like me with a big expensive monitor.
