some info that may get someone out of a jam.
I bought a s/h m805 few days ago, no lens board no neg carrier and shop owner said bulb blown. so i bought one from him 19 euro
when i got home put in bulb an it blew. got out multimeter to check voltage and i was getting 19 which made no sense.
as im 160 miles from nearest pro photo shop (dublin) i went looking for a bulb 24v 250 w reflector. none to be had
however one shop had projector bulbs 24v 250w which they kept for schools at 8 euro . it was the same 2 pin type but without the reflector. I plugged it in and no problem, so i carefully scraped out the 'cement' from between the reflector an bulb of the old one and removed it. I slid the new one into the reflector and pushed the connector on and clipped it into place.
Job done and at less than half the price and local too. now to make or buy the neg carrier an lens board an play with the toy!
So if someone is in a jam and cant get a bulb quickly this may be a work around and possibly less expensive too. im not even sure if i will bother sealing it back with fire cement
Consider that the hot spot of the lamp (filament) needs to be centered at the focus of the parabolic dish formed by the reflector or else you won't get even coverage from the beam.
Chances are that the design of the reflector is such that the relatively large hot spot of the filament will naturally center itself in the focus but you should verify that just to be sure. Otherwise you are likely to end up with hot spots and dead spots in the field of light projected on the easel.
It might be just as simple as wiggling it the right way or even just setting it, carefully, down on the base of the lamp but one wrong bump might make it move out of place at the most inopportune moment.
You might not need refractory cement. Just a dab of high-temperature silicone stove gasket cement from a squeeze tube might do the trick.
I'm pretty sure the light goes into a diffusion box before it gets directed out towards the lens. Critical placement of the filament should be relatively unimportant in this case.
You are probably right.
Still, I propose that he should give it a once-over to be sure.
Mind you, I'm a little bit battle hardened on the subject of focusing lamps in their reflectors.
If you replace the lamp in a cinema projector but you don't ensure that it is properly aligned you can burn the film. Yes, even at 1/24 of a second you can still burn film! Ask me how I know this.
As much as I know Frank is right, there is still that little knee jerk reaction in me that says, "Check the alignment. The time you spend, now, might save you trouble later on."