Re: Sony KDS-R50XBR1 yellow stain
Check for discolorations on a white background (use a picture or some other still image), My parents have had 3 optical blocks replaced this year in their 50" XBR1.
The first one was when the stain showed up under regular programing (after just over 2 years use) & the next 2 came very quickly because after replacing the optical block I went straight to a white screen & checked very close.
I saw green & pink discolorations, these would not be seen on regular programing but may have just gotten worse over time.
Sony has offered to replace their set, so far they have offered to replace it with a new KDL-52XBR6 for $1200 but I may have them wait to see the new XBR7 before they decide.
So check your set closely, this one was bought by me in Dec of 2005 & Sony extended the optical block warranty to 3 years so this one was about to expire.
It's a shame really because when it's working right it has an amazing picture!