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Topic: Focusing the xenon arc lamphouse

Harry Robinson
Expert Film Handler

Posts: 155
From: Franklin Tennessee
Registered: Dec 1999

posted 02-29-2000 09:50 AM

My latest addition in my quest for 35mm home theater is an old Christie H-10 lamphouse with a 110v rectifier. I've asked a lot of questions about this thing among other collectors and some parts dealers. I'm getting mixed messages.

Four questions:
1. This unit came without a heat shield glass. Other enthusiasts have told me that this shouldn't affect the ability to focus the unit. On the other hand, parts dealers have told me the opposite. Hmmm...Which is true?

2. My Super Simplex came with a three-point base. Most people have told me that the lamphouse can never be properly focused without mounting it on an RCA enclosed base. One friend said, however, if I tap a couple of holes in the bottom of the lamphouse mounting area (for lack of a better name) and install some set screws I can save some money. The average price I'm looking at for the enclosed base is around $250. We're currently building a house and money is tight. Can this be done?

3: A friend said I shouldn't worry about the heat problem from the lamphouse because I'm only dealing with a thousand watts. Is this true?

4. I've been told the H-10 can handle up to 1600 watts. Is this also true?

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Bill Purdy
Expert Film Handler

Posts: 139
From: Seattle, WA
Registered: Oct 1999

posted 02-29-2000 10:45 AM

Even though I am not at all familiar with this lamp house, a couple of things in your questions jumped out at me. First, I once used the three point base with an ORC M-1000 lamp and had to make some 1/2" or so "shims". Another dodge is to get some all-thread rod and lots and lots of nuts and washers. Whatever it takes to make the lamp house line up with the optical center of the projector. Regarding the heat shield, (remember that I am not familiar with this lamp) often the heat shields are as much a part of the ventilation control as they are anything else. It may well be necessary for the purpose of ducting the cooling air where it is needed.....and it is needed no matter how small your bulb may be.

------------------
Bill Purdy
Comonent Engineering

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000

posted 02-29-2000 11:13 AM

Harry:

As Bill notes, you need to be careful in removing a component like a heat filter from the lamphouse, because it may affect the airflow and ventilation within the lamphouse.
Even without a dichroic mirror or heat filter, it's unlikely that 1000 watts would permanently damage 35mm film unless you misalign the lamp and "hot spot" it. But the extra radiant energy is absorbed by the film (especially silver-image B&W), causing more tendency to focus flutter. So use the heat filter if you can. Getting rid of the infrared and ultraviolet energy is very important with lamps 2000 watts and larger.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Professional Motion Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 02-29-2000 01:14 PM

1. Without that heat shield glass, you won't be able to get a good focus of light in that lamphouse. You'll need to get it. However, you can run 16mm or Super 8mm quite nicely without it.

2. Not sure on the 3 point base. I've never set up a Christie on a 3 pointer.

3. Heat exhaust is really not a problem. Your booth will get a little warm, but you can exhaust straight into the room so long as the blower fan is functioning on top of the lamphouse.

4. I've never heard of an H-10 running anything other than a 1000 watt, but I do know many people run 1600 watt lamps in the integrated ORC lamphouses and get superior light even only with the 1000 watt supply.

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Ken Layton
Phenomenal Film Handler

Posts: 1452
From: Olympia, Wash. USA
Registered: Sep 1999

posted 02-29-2000 01:27 PM

Does your lamphouse have a conversion kit in it? Strong made a conversion kit that basiclly guts out the interior and replaces everything inside so it's like a Super Lumex.

Christie should be able to sell you a new heat filter.

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Martin Frandsen
Master Film Handler

Posts: 270
From: Denmark, Europe
Registered: Jun 99

posted 03-19-2000 08:41 AM

A bit of subject but: is it ok to clean the mirror (reflector) in the lamphouse or is it best to leave it with the dust on. It's a Cinemeccanica CX1600, the mirror probely is as old as the lamphouse, that's 10 years of dust siting on that reflector. Im told not to wipe the dust away or else i might scracth the surface of the mirror

is that right? i guess if i wipe the dust away more light will hit the screen. ( not much, but still it's better with a clean reflector )

How can you see if the mirror needs to be replaced?

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Rick Newton
Film Handler

Posts: 4
From: Portland, Oregon, USA
Registered: Mar 2000

posted 03-19-2000 09:09 AM

The most important thing is to get a string alingment kit as well as a CH 10 manual. Next follow the instructions for distance from the apex of the mirror to the apeture. When the string alignment kit is set up, you will be able to tell how much to move the lamphouse up-down or side to side.You should see only one image of the string in the mirror from any angle.
The missing condensor lens is not a real concern with a 1kw lamp. You should know that this type of lamphouse is not known for excellant light output from a stock reflector. The Strong kit is about $800 and a Pheonix kit is about $1600.
Rick

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Rick Newton
Film Handler

Posts: 4
From: Portland, Oregon, USA
Registered: Mar 2000

posted 03-19-2000 09:23 AM

quote:
Originally posted by Martin Frandsen:
A bit of subject but: is it ok to clean the mirror (reflector) in the lamphouse or is it best to leave it with the dust on. It's a Cinemeccanica CX1600, the mirror probely is as old as the lamphouse, that's 10 years of dust siting on that reflector. Im told not to wipe the dust away or else i might scracth the surface of the mirror is that right? i guess if i wipe the dust away more light will hit the screen. ( not much, but still it's better with a clean reflector )
How can you see if the mirror needs to be replaced?

Clean the mirror with a lint free cloth and a non-abrassive cleaner. A clean mirror will improve the light output. If you have a glass reflector check to see the condition of the coating, if it is flaking or badly sctached you might want to consider recoating. If you have a metal reflector, check for coating peal and dents from exploded lamps.
Rick

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John Eickhof
Jedi Master Film Handler

Posts: 588
From: Wendell, ID USA
Registered: Jan 2000

posted 03-19-2000 10:32 AM

The glass piece on the snood of the older CH-10 & 20 is in fact a negative lens, or
a beam spreader, it enlarges the focused
beam of light enough to fill the 35mm scope aperture at the given working distance. The
lens used in the H-10 was uncoated, as the amount of heat is nominal. (it is hotter on the film without the lens) The lens on the
H-20 was caoted with a dichroic UV reflecting material to reduce the heat on the film. This lens IS necessary for proper light field from
this lamphouse. The H-10 can be fiited (with adaptors) to take a 1600 watt HS type bulb..
however, the 115V power supply is a 900 watt
type and it will not handle additional current requirements thus your light output
wont be any better. If you are using this
lamp on a smaller screen..say 5'x12' you should have ample light running at about 50 amps DC with the negative lens installed!
Your Super will have no problem with this, in fact you may want to get a 3 blade shutter to
reduce flicker. Contact me as I have many used negative lenses in stock, and also can supply 3 bladed shutters for most machines.
email.. jeickhof@nteequip.com

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Martin Frandsen
Master Film Handler

Posts: 270
From: Denmark, Europe
Registered: Jun 99

posted 03-20-2000 10:39 AM

Thanks for the info Rick

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Harry Robinson
Expert Film Handler

Posts: 155
From: Franklin Tennessee
Registered: Dec 1999

posted 03-20-2000 03:02 PM

Thanks for all the replies to my question. Just a note...I went ahead and got an RCA closed base. Now all I need is the condenser lens. I'm hoping to have a scope image approximately 13' by 6' when the room is done. I'll have a 25' throw to the screen. Any suggestions from you guys who have screening rooms are welcome.

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 03-20-2000 04:40 PM

Being i a home i asume there is a budget and as such the short through ISCO or schnieder lens are out of the question
Most VidoeScope anamorphs will focus down to about 25' after you twist them off the scale

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John Eickhof
Jedi Master Film Handler

Posts: 588
From: Wendell, ID USA
Registered: Jan 2000

posted 03-21-2000 12:05 AM

The RCA pedistal is a nice one! It has the
horizontal shift mechanism for running 2.55
Magnetic only prints. However, when it comes to aligning your lamphouse to the projector aperture, The RCA does not have the convenience of a movable lamp table. All the alignment adjustments are on the hanger bracket where the soundhead bolts up. The entire bracket slides up/down/and side to side by loosening the four large bolts & nuts
then adjusting set screws to move the projector / soundhead. Do not loosen bolts any more than necessary as the machine will change alignment when you tighten them up.
It can be a tedius proceedure, but with some patience you should be able to align the system fairly well. Good luck. Remember to make sure the projector & soundhead sre bolted onto the hanger firmly before adjusting things. If you need further help. contact me.

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