So you've got a nice commercial projector but the bulb is going dim. Time to replace it. Look on Ebay and WHAT THE HECK !!! $250-$500 for a 2000 hour bulb.

Well OK you say I'll just go to LumenLab forums and find out how to replace my expensive lamp with a cheaper one.

Not so fast.......

There are several problems with this.

1. The projector will need to be tricked into thinking a Manufacturer replacement lamp is still in it. And this is sometimes very hard if not impossible to do. There are several sites on the Web dedicated to trying to bypass the electronic circuits that detect the lamp so you can replace it with a different one. You will have to do some searching to see if your projectors lamp detection circuit can even be bypassed.

2. Commercial projectors use lamps with very small arcs that work perfect with their small Lcd's and small optics. If you try to replace the lamp with a Metal Halide or a Halogen, the lamp arc is much bigger. And the results will be a much dimmer projection even with a much brighter lamp.

Now there are some advancements being made in LED and Xenon lights. But as of now they are not really a viable option.

There is a member of the DIY Audio forums that might can help though. He sells replacement lamps for around $100.
See this thread: Here

So there you go, hopefully this helps.