Hi everybody,

I have an NEC SX4000 digital projector which needed cleaning the dust off its 3 DMDs.
I tried to blow pressurized nitrogen (which is a very dry and very clean gas) with a small plastic tube (at about 80 psi) on each of the 3 DMDs but they are pretty hard to reach, even after removing the "optical engine". It is impossible to blow the gas directly on any of the 3 DMDs at a right angle; only a "lateral" or parrallell blow" through a 1/32th inch gap is possible. So I still have large red blotches on my 20 foot by 10 foot screen, specially during scenes where black images are displayed. When images with a lot of white are displayed, the same blotches are blue.
Please take note that the optical engine cannot be disassembled to permit direct access for cleaning the 3 DMDs because the engine would then require a costly factory re-alignement of these 3 DMDs after re-assembly (apparently only possible at NEC facility in Japan).

Anyone, please, has experience in cleaning DMDs on this NEC model ?

I think you're at the point where you do need to contact NEC to get them to do this cleaning/repair.

Agreed. The Nighthawk series is a very complicated projector to work on and requires special tools and training. To get at the dust means disassembly of the optical engine, not something for the DIY person.