Home made projector!

[Chernobyl]

tbh thats pretty much what I've done (except I changed the OHP bulb )

I took the bulb platform out, hammered it flat and stuck the new bulb/reflector on it, placed the triplet lense on above them.
Wired up the new transformer, job done.

There are some hard jobs to do, this isnt one of them!

[cyrax83]

the german page ... is there any other place to get that bulb ? i cant even read the site so i know nothing about postage to sydney, australia, or how to pay etc etc. Will it fit in my ohp (3m 9700) ? and would these be available locally ? whats the exact name of the component ?

Thanks

[Chernobyl]

Undoubtedly there are many places you can get a bulb.
You need more than the bulb though, an ignitor, fittings and ballast are required too.
The German site has specialised in stocking only parts for home made projectors, you cant go wrong buying from him.
You can go really wrong buying somewhere other than a home projector shop as the bulbs are not designed for a projector, you can easily get a part that isnt good for the job!

The bulb spec is
HQI or HRI -TS

CRI >= 90
5000K to 5700K Daylight colour temp
250W / 400W
20,000 / 36,000 Lumens (approx)
UV Stop (only for 250W, use a UV filter for 400W)
Smallish size/fittings fine for an OHP
Life 6,000 hours +

ie mine is HRI-TS 250W UV W/D Daylight, 6000 hrs, CRI 95, Colour = 5200K
The W/D is a reference to Daylight colour temp. D usually means Daylight and should be around 5200K.
Your current bulb has a colour temp of 3700K and will look more yellow.

If you dont get the right colour temp, it will look either more yellow or more blue. The CRI is how the colours are balanced all the way from Red to Blue. A high number means that objects lit by the light look close to natural.


There are other types of bulb (other than HRI / HQI) that will work too but I dont speak from experience with those.

Handle the bulb with care, no finger prints or dirt are allowed on it.
Clean the bulb with a vinegar based cleaner if it gets any marks on it. It is essential nothing is able to burn onto the glass as it can crack.
Careful when powering up to test, make sure you are shielded from the bulb, in rare cases they can explode! Keep the test short unless it is built into an enclosure.
Once powered up, they take a few minutes to reach full brightness/colour, do NOT look directly at it without good sunlasses!!
Even then dont look directly at it.

Use google to translate the German site while you browse. Once you know what you want, purchase through the original site.
You can find out the delivery charges by contacting the site owner here
http://62.75.177.102/shop2/index.php...&2=1&kontakt=1
He speaks English

[cyrax83]

thanks chernobyl big help. I've emailed the guy about shipping and pricing. Hopefully he can give me a good deal.

6000 + hours is mighty tempting. Does the bulb deterioate in quality during these hours or does it remain at optimum brightness all throughout its life then just suddenly die ? or does it slowly fade away ?

[Chaz]

I believe the bulbs slowly deteriorate in quality, down to about 50% of their original brightness when they die. I cant remember where I heard that though.
Shipping prices appear to be shown on this page, cyrax.
http://62.75.177.102/shop2/index.php...rbedingungen=1

Chernobyl, from looking at the photos you took while you were switching the bulbs, the general layout of the OHP doesnt appear to be the same as mine. Do you think I'll still be able to fit the MH kit ok?

[cyrax83]

also maybe you guys can answer this one. on the left hand side of the projection in the middle of the screen i've got concentric circles that ripple out towrds the middle of the screen and below. kind of like when you throw a stone in a pond. you can see the colour spectrum.

whats the deal with this ? when i switch to my second bulb the circles still appear. is this permanent damage on my ohp ?

[Chernobyl]

Chaz
I dont know if your OHP can take a MH bulb without modifying it, portables are trickier. Can you tell me the height from the floor of the OHP to your Fresnel lense. I'll compare it to mine.
It may be necessary to cut the bottom out and extend the height a little in order to fit a MH bulb, we shall see.


Cyrax
Chaz is correct, the light power is supposed to be approximately 1/2 as strong by the end of its life. The colour spectrum can shift slightly too.


Are the rings you get still present with just the OHP and no LCD?
I can think of 3 reasons you are getting this effect

1) You can adjust the bulb height (I hope). The effect may adjust out.

2) if the effect is present only with the LCD on:
All OHP lights produce strong UV. The OHP glass should reduce this so you cant see immediate effects from UV. If you are seeing red rings on your LCD, it is likely to be caused by excess UV.
It doesnt sound like this.

3) If it is a rippled light effect only then adjusting the height of the bulb may lessen the effect. You can also try raising the LCD a little to see if the effect goes away. Raising/lowering the Fresnel may help too.

If your Fresnel lense is unsuitable, you can buy one that is from the German shop pretty cheaply.
Try removing the fresnel lense to see if the pattern goes away then you know if you need to play with the Fresnel.

[cyrax83]

how do i actually adjust the height of the light bulb ?

[Chernobyl]

My ohp has a colour temperature knob.
When I turn it, it affects the colours in the corners of the screen.
I adjust it til the colours match the middle.
This is raising/lowering the height of the bulb.

Hopefully you have one of those too.
I think what you are seeing is an interference pattern from the Fresnel. By moving the bulb, my hope is the angle the light hits the lense will change and make it work as it was intended. I hope the Fresnel is good enough.

[cyrax83]

the colour knob on the bottom of the ohp doesnt even do anything when i turn it *scratches head*

[Chernobyl]

maybe its broke?
Can you check inside to see what happens when you turn it?

Try some of the other suggestions I made

[MiccyNarc]

Hello folks, I'm looking to go with this project but I need help.

Okay, I got an OHP, but in taking off and cleaning the glass, I ended up breaking one of the fresnel lenses, rendering it useless. I'm looking to purchase one now, but I can't find one with appropriate size (around 15" to support an LCD screen) that doesn't cost around $300. I've been searching ebay but none of the sellers list the size >

So, could you recommend me an OFP?

Also, I want to use this for games and movie watching, what would you recommend for someone on a budget (aka me :P)

Thanks alot for any input, I really appreciate it.

(PS. I live in the USA, I know most of you live in the UK, correct?)

[Chernobyl]

Hiya, welcome to the project!
I live in the UK, theres quite a diversity of interest round the world though

Your OHP has more than one fresnel? Interesting.
What OHP is it?

I'm not sure if you are asking should you get a new Fresnel or OHP. It seems like you are trying to say OHP (not OFP).

If you have a good OHP already, you should replace the fresnel lense.
If not, its difficult to know what is available on Ebay cheap. If you post a link to any that you like the price of I can tell you some positives and negatives.

I recommend what I have, the 3M 1750.
Its a 400W triplet lense, dual bulb, has an adjustable bulb tray.
You cant get it in the US as far as I know though.

When you say what do I recommend for a person on a budget, are you referring to an LCD or OHP or both?

[cyrax83]

the guy quoted me 50 EUR (~80 USD) for shipping to Sydney, Australia, thats ridicoulous for just a bulb

[Chernobyl]

Originally Posted by cyrax83

the guy quoted me 50 EUR (~80 USD) for shipping to Sydney, Australia, thats ridicoulous for just a bulb

Its a bit more than a bulb, its the full kit. The transformer weighs a lot!
You need to look around for bulb/parts suppliers local to you if that is too much.
Even with the cost for your postage, the total cost is still cheaper than I can buy the parts over here.

If you do find a more local supplier, make sure they can supply the Ballast (transformer) and the Ignitor to go together. Dont forget the fittings that the bulb plugs into!
Tell them what your project is (if they seem interested) as someone there may be into this as well.
You will also need to find another supplier of the rear reflector and any other bits you fancied getting.

[MiccyNarc]

Originally Posted by Chernobyl

Hiya, welcome to the project!
I live in the UK, theres quite a diversity of interest round the world though

Your OHP has more than one fresnel? Interesting.
What OHP is it?

I'm not sure if you are asking should you get a new Fresnel or OHP. It seems like you are trying to say OHP (not OFP).

If you have a good OHP already, you should replace the fresnel lense.
If not, its difficult to know what is available on Ebay cheap. If you post a link to any that you like the price of I can tell you some positives and negatives.

I recommend what I have, the 3M 1750.
Its a 400W triplet lense, dual bulb, has an adjustable bulb tray.
You cant get it in the US as far as I know though.

When you say what do I recommend for a person on a budget, are you referring to an LCD or OHP or both?

It has 4 fresnel lenses (well, actually, 3 lenses and a sheet of Acrylic that also acts as a lense and holds them all together, which is what I broke)
It's a really old OHP that I got from my church, I doubt I could find a replacement for the lense.

So I'm looking for a new OHP right now.
I think I could find a 1750, just not on Ebay (at least right now).

When you say what do I recommend for a person on a budget, are you referring to an LCD or OHP or both?

LCD.


Thanks alot!

[Chernobyl]

Hehe, readers of this thread know I can only recommend the Iiyama E380S as its the only one I have working. I tried a BenQ and it became damaged far too easily, so cant recommend them.

The Iiyama E380S is top class as its very good for everything.
Some of the very recent LCDs have a faster refresh rate and are more desirable for gaming but I have no idea if they are suitable for this project. They are undoubtedly not budget models either

You need a monitor that has a contrast ratio of at least 400:1 and 16ms or less refresh rate. I cannot tell you which LCDs will go on an OHP with the electronics out of the way of the light.

[cyrax83]

i can recommend you the CMV CT-529.

disassembles the same as the iiyama and good stats.

works very well

[MiccyNarc]

Originally Posted by cyrax83

i can recommend you the CMV CT-529.

disassembles the same as the iiyama and good stats.

works very well

http://www.newegg.com/Product/Produc...82E16824024004
That's the closest match I can find in US stores.

The Iiyama E380S is top class as its very good for everything.

M'kay. The Iiyama US store lists it as $240, which is reasonable.

EDIT: I think I'll be going with the CT-520, as I found a series of pictures showing disassembly.
http://k1h.blogspot.com/2005/02/proj...lcd-found.html

[MiccyNarc]

Chernobyl:
It seems all of the projectors in the 1700 line only have 10x10 inch stage areas (which I'm assuming is where you put the LCD)
Isn't that too small for a 15 inch LCD?