[Ned Fletcher]

Dear Forum members,

I have greatly enjoyed buying the right equipment for my DiY projector and putting it together, so this is a message specifically to thank you for all your endeavours and ongoing support. I love this place.

But, to my problem, so far I have come stuck on concentrating the light from the metal halide bulb onto the overhead projector's head. I attach pictures below and ask if anyone knows..

what is missing in my setup to concentrate a picture onto the wall?
I have installed the Halide ballast and lamp + mogul into the space? but the light shines off onto the cieling and avoids the 'lens-head'...

how do I concentrate the light into the 'head' part and where do I get that 'lens' from in the UK / USA (International shipping) is it reasonably priced? is this a collector lens or a fresnel lens? I've looked at the Lumenlab DIY projector PDF and am finding difficulty in making head or tail.

Can I make all of these necessary adjustments without distorting the size of the projector? I don't have the right tools to build a box from scratch you see... (the bulb JUST fits inside, and with a few modifications can rest perfectly on it's original reflector... so what do I do now that I've got the bulb working with sufficient cooling INSIDE the original 250w OHP?

Do I need an IR filter? EBAY UK is my best source for all of this so far, I really want to get this done with to host a village video weekend! all help appreciated and thank you!

[Ned Fletcher]

EDIT**: I have built an enclosure box that fits around the TOP part of the projector, making it into a box-like shape, this has not helped in reflecting the light INTO the lens, in fact it made no difference....

I believe I clearly need some sort of lens strapped to the lightbulb, and a reflector of some sort....Lumenlab did a 400w version, would that same setup work for a 600w bulb?

[SupraGuy]

Well, one, your lamp has a really long arc. The SMALLEST area that the fresnels can fit that light into would be the size of the original arc. Properly focused, it would be the size of the arc multiplied by the distance from lens to fresnel divided by the distance from fresnel to lamp, which will be larger than the lamp chamber.

I think that you need a differnet lamp setup myself.

Note that you want as few reflections as possible in between the LCD and the lens, unless you want to project a kaleidescope image onto your screen... I doubt that this is the case.

[Ned Fletcher]

Dear Supraguy

Is there a suitable reflector that I could replace the original reflector with that will reflect the light into the OHP head? I feel I'm so close... I've just paid a huge ammount on this light setup....it gave me the freaks to think of having to buy yet another light

SupraGuy, on Feb 23 2010, 12:26 AM, said:

Well, one, your lamp has a really long arc. The SMALLEST area that the fresnels can fit that light into would be the size of the original arc. Properly focused, it would be the size of the arc multiplied by the distance from lens to fresnel divided by the distance from fresnel to lamp, which will be larger than the lamp chamber.

I think that you need a differnet lamp setup myself.

Note that you want as few reflections as possible in between the LCD and the lens, unless you want to project a kaleidescope image onto your screen... I doubt that this is the case.

[SupraGuy]

It's unfortunate that the setup cost you so much. How much was the lamp itself?

The 575W lamps have a very small arc, and (IIRC) cost about $90. They have a shorter lifespan too, unfortunately, but will certainly do the trick for light delivery. Not sure about the overdriving of them to 600W, but that seems to be within reason, anyway. Also, if that's a coil 'n core ballast that you've got, it may not want to strike the 575, but with the shorter arc, it OUGHT to be able to.

Other than that, looking for a compatable 600W lamp with a shorter arc (About 40mm is about the max that I'd want, and less than 30mm would be best.) would be a good idea.

[giorgaki]

http://www.usponics....mp;productId=23

Pretty cheap, not sure about arc length, 70600 lumens, cri 72 (slightly low but many people have used lower cri lamps), 4829k colour temp

This post has been edited by giorgaki: 25 February 2010 - 04:32 AM

[Ned Fletcher]

Thank you so much for the help so far, it is frustrating to not be able to get this into my projector, but oh well, at least i tried. I paid $280 for ballast + lamp + reflector..i've ruined the reflector trying to fit it into the compartment...

so what's the next step? ebay is a pretty easy thing for me to order from so ...

www.ebay.co.uk


what terms do i insert to find this in there? iirc lamp?

SupraGuy, on Feb 24 2010, 08:33 PM, said:

It's unfortunate that the setup cost you so much. How much was the lamp itself?

The 575W lamps have a very small arc, and (IIRC) cost about $90. They have a shorter lifespan too, unfortunately, but will certainly do the trick for light delivery. Not sure about the overdriving of them to 600W, but that seems to be within reason, anyway. Also, if that's a coil 'n core ballast that you've got, it may not want to strike the 575, but with the shorter arc, it OUGHT to be able to.

Other than that, looking for a compatable 600W lamp with a shorter arc (About 40mm is about the max that I'd want, and less than 30mm would be best.) would be a good idea.

[Ned Fletcher]

yes it's a coil and core ballast (big black heavy 6kg thing). so where do i get these light bulbs from? will it fit my mogul base?

SupraGuy, on Feb 24 2010, 08:33 PM, said:

It's unfortunate that the setup cost you so much. How much was the lamp itself?

The 575W lamps have a very small arc, and (IIRC) cost about $90. They have a shorter lifespan too, unfortunately, but will certainly do the trick for light delivery. Not sure about the overdriving of them to 600W, but that seems to be within reason, anyway. Also, if that's a coil 'n core ballast that you've got, it may not want to strike the 575, but with the shorter arc, it OUGHT to be able to.

Other than that, looking for a compatable 600W lamp with a shorter arc (About 40mm is about the max that I'd want, and less than 30mm would be best.) would be a good idea.

[Ned Fletcher]

I can't seem to get it for love or money to work... is there anything that I can do? can I use the parts (lenses etc...I already have), to build a new projector? there is very little on projectors and how to build them online...

[giorgaki]

You can definitely use the lenses. Have a look into that 600w lamp I posted. you should be able to use that. Although the arc seems slightly large, you should be okay with it I think