Anyone with experience on Dell DLP projectors?

[N2IXK]

Just inherited a Dell 1200MP DLP video projector that needs repair. The unit will start up normally, go through the lamp warmup, and then run normally for about 30 seconds. At this point it will either:

A: Go to monochrome, start making a faint whining/whirring noise like a fan or motor running, and lock up (image freezes, no response to remote or buttons, except for power off)

or:

B: Simply shut down the lamp, go through the cooldown cycle, then go to sleep.

I have already tried:

2 different replacement lamps (yes, the lamp timer was reset).

Cleaning the dust out of fans and filters. All fans appear to be running OK.

General internal inspection for loose connections, bulged electrolytics, etc. (nothing obvious found).

Resetting to factory default settings through the menu.

This might make a nice unit for home use, and I would like to get it up and running if at all possible. It would seem that all the "big buck" parts like the DLP chip, lamp, and optics are OK, since it does function properly for a short time. I haven't been able to find a schematic anywhere yet.

Anybody out there have any experience with these units? Any "common failures" to be on the lookout for?