As I posted on the XBR1 thread, mine is being replaced with a 2. While waiting, I decided to see what raising the temp. on the 1 would do for the non-uniformity color issue of the replacement OB as just warming up lessened it ever so slightly. Prior to my OB replacement, I had always run in reduced power mode. Considering the speculations temperature was causing the problems I wanted to determine if lower, rather than high temp. was a possibility.
I took an extremely breathable cloth fiber material and draped it over the entire back and sides of the set, around the top of the stand and sealed it to the stand. It is not directly touching any part of the ventilation area of the set and is approx. 1/2" off the back at the fan outlet. You can feel the warm air from the fan penetrating the fabric. This did, however, almost completely eliminate the non-uniform (green and pink splotches) areas on the screen after a little more than an hour of operation. I have left it on for 12 hrs and the internal temp. has not been raised enough to trip the heat sensors, that's how breathable the fabric is.
I do not recommend anyone with an XBR1 that is not being replaced trying what I have done, nor would I even consider it for an XBR2. Based on the effects of a 30 min. warm up time for the XBR1 and the increased wattage bulb (hotter) in the XBR2, I speculate the cause is temperature related (too low of a temperature in the XBR1). I believe the additional wattage (hotter) bulb is part of the solution in the redesign of the XBR2.
If my hypothesis is correct, this raises a concern about using power saving mode on the XBR2. This will slightly lower the internal temperature, possibly causing very minute, and slowly progressing problems over many months of use. My XBR1 was perfect for the first 6 months and SLOWLY developed the "Yellow Stain" which then slowly progressed across the screen. I am not stating for a fact that improper (lower) temperature is the cause, but you can bet my XBR2 will be run @ full power and adjusted accordingly for PQ.
A towel? Come on, give a guy a little credit here.