Today, the optical block on my Sony KDSR-50XBR1 was replaced. Over the past 6 months or so, the picture quality had slowly degraded, with the appearance of a yellow "stain" appearing over much of the display. This is a known problem with first-generation SXRD displays, and there is quite a lengthy thread discussing it on the AVS Forum. Earlier this year, Sony responded to the high volume of complaints by extending the warranty on all XBR1 displays until October, 2008. I finally decided to take them up on the offer this week.
Sony eSupport directed me to the local support dealer, Georgetown TV and Video, which is a few miles from my house. Surprisingly, they were able to get the part in under two days and schedule an appointment. They were originally scheduled to perform the service on Thursday, but were able to come out a day earlier.
The support call took about 45 minutes to perform. The result is absolutely stunning. Picture quality has improved tremendously, with bright clear whites being displayed once again. The display looks like it did when it was brand new. The tech who performed the swap stated that the new optical block had been completely redesigned by Sony. The previous optical blocks had problems with UV radiation from the bulb affecting the blue SXRD panel (hence, the yellowing effect). The new OBs have additional filters installed (supposedly), so the yellow stain should no longer show up after extended use. While this remains to be seen, I still have another year on Sony's warranty extension, and another two years beyond that on the extended warranty I purchased with the display.
The tech also mentioned that he could clean and align the guns on my 65" Toshiba RPTV, so I'm probably going to schedule an appointment in the near future. It's good to have my TV back!