In article , doozer
writes
This maybe a little off the normal beaten path for this group but it
has some knowledgeable people and this certainly falls into the
category of DIY. I have already asked on AV Forums BTW.

You're probably going to think I am mad for even suggesting this but I
am toying with the idea of building an external light source for my
projector to reduce the cost of lamps.

As someone who has worked with optics for projectors, I can tell you
that it won't work. You need an immense amount of light intensity and it
has to be focused just so (if you've ever fired up the projection lamp
with the housing open, you will know just how bright it is - you can't
see anything else for a few minutes). Many man hours of research go into
producing efficient optics for the projection beam. The lamps are
discharge (arc) types and have control gear in the projector - you can't
just replace them with any old lamp.

What you can sometimes do is buy the lamp itself separately, as the
manufacturer replacement often includes the reflector and housing. This
can cut down the cost considerably. Find the manufacturer code from the
lamp itself and google for it.
--
Tim Mitchell