Phillips model 50PL9126D/37 lamp problem

Since the lamp runs at its maximum all the time it's safe to bet that the fan runs at its maximum all the time. Check the ventilation path for obstructions. Also see if you are blowing air with the extra fan on the lamp ballast. Not sure if a problematic ballast would display as a lamp failure though. How many hours on the lamp? If it's getting old (2000 + hours) that may also be a reason for this problem.

I suspected the lamp could be going faulty, but I haven't been able to put together the fact that the temperature indicator light doesn't show when it shuts down, but keeping the area cool with a fan keeps it running. I will try to thermally cycle the ballast to see if I can repeat the problem, if I can access it without having to tear half the set apart. A schematic would be helpful, and I'll see if I can find one. Until then, thanks for the response, and I'll update the progress.

You mentioned above that the lamp failure light blinks then the set shuts down.

The ballast should be easy to spot and it's usually fairly close to the lamp structure. You'd need to know how much current the ballast draws after the lamp is lit. The lamp runs a few thousand volts at startup then backs down to around 60. However the current draw is as great or greater when lit and stablized. You might need a service manual to track this one down unless you get lucky and shotgun the lamp and ballast which is a huge expense that i wouldn't recommend.