I've had my 36" Sony Wega (sorry exact model number escapes me) for about 2 years. Recently, I've noticed that on occasion after being on for more than 30 minutes the set will begin to emit a "high pitched tone". It's not very loud but it is noticeable and annoying. Unfortunately, this appears to be somewhat random in occurrence as sometimes I'll have it on for hours and it won't do anything. Anyone else here have this problem, know what causes it, or how it can be fixed? Thanks.