We were called out to trouble shoot a couple of large ceiling mounted projectors at a local church. They were having trouble with one projector in particular. Kept going out. We took it down to take a look inside and discovered corrosion from water penetration. We searched all over trying to find where the water was coming from with no luck.
We finally discovered that the warm air from the attic was heating up the inside of the suspension pole and there was an A/C vent blowing on the outside of the pole causing condensation inside which was running down into the projector. It was only a very small amount but enough to cause some internal damage.
We were able to plug the top of the pole so the hot air would not travel down the inside and also insolated the pole. We also diverted the air flow from the vent away from the projector as best we could. Then we fashioned a "drip pan" to divert any future condensation. This should solve the problem.
Just beware of this when ceiling mounting projectors.
