I have the exact same problem for the same projector. The issue is the blower for the bulb itself, which is mounded in the heart of the projector next to the light pipe. Over time the blower blades accumulate dirt and crud which reduces the effectiveness of the blower to cool the bulb. In order to get to this blower you would have to completely disassemble the projector, the blower is the last component you will be able to remove. I highly recommend a service center perform this maintenance unless you have a profession in electronics, are familiar with protection from electrostatic discharge, and your warranty is expired. If you take the risk of cleaning the blower yourself, try as best as possible to remove all traces of dirt from each blower blade. It is a tedious task. Removing the surface dirt is easy, just use a vacuum and a brush, but the burned in dirt which builds up in the pores of the plastic due to heat and time is very difficult with out some sort of solution or mild abrasive, and as everyone should know, liquids and electronics don't mix. There are dielectric cleaners and rapid evaporation cleaners available for electronic equipment that you can try. The only issue is once the blower has gotten dirty enough over a long enough period of time, it will not take long until the problem returns. The cleaner you get it, the longer it will last before it needs another cleaning. If the blades will not get clean enough and the problem occurs at too frequent an interval, then a replacement blower or complete servicing is recommended.

Clean out the filters by taking the case of then before powering the unit on (make sure the lamp is cold) take out the lamp ad clean off any dust etc and check at the front of the unit centre that the disc for the DLP isnt broken, a typical fault on these machines. otherwise i did have one machine that switched off due to low mains voltage!! 198v instead of 220v (here in spain)