The Optomas are notorious for short bulb life and I found the solution, but you may not like it. Its case is beautiful on the outside but poorly designed for heat evacuation. I went through my second lamp within 1000 hours. I found it was not a bad lamp, as the unit got older it created more heat and the unit shut down due to the heat.
After removing the cover, careful it's only plastic they screw into; I removed the air duct, mounted next to the lamp chamber, so the air and heat were not restricted in any way. I replaced the cover, leaving the air duct and side cover off. I put my bad bulb back into place and it has worked fine for over a hundred hours now.
The downside is that the light is not trapped without the side cover, so I had to build a box to enclose the total unit and trap the light without stopping the airflow. I was able to build it from the same drop ceiling grid & tile I had used for the room. I built the frame down from the ceiling grid; left the projector mounted where it was and positioned the approx. 24x48 box with the good side of the projector at one end. I masked off or blocked the other side of the projector, within the box, to let the air flow into the open ceiling but block the light from shinning towards the projector. I left a section directly behind the projector open with a black velvet curtain cover for access. I expect a longer life on any new lamps at this point and when this present lamp finally goes, I intend to reuse the 1st lamp I removed a year ago.
Hope this helps.