Film-Tech Forum ARCHIVE: H-20 problem

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Posted by Richard B. Perrine (Member # 409) on 01-15-2010, 11:33 PM:

Have a theater here that's still usuing th Christie H-20 lamphouses with the "new" replacemt reflectors and CXL-20's.

The bulb forward/back is messed up and won't move...I have fixed that yet.

Years ago, I ran an H-20 with the new reflector and same 2K on a much bigger screen (20x45')and got a lot of light.
Here the light is even, but very dim. Screens here are probably 14x32'....lenses are newer and look good.
Century SA vs a DW is only difference and screen size.
I alway had Osrams at the other theater....so here;s my question.

After replacing the reflector....should a different type bulb be used instead of the CXL-20?

Posted by Jeremy Weigel (Member # 4208) on 01-16-2010, 12:14 AM:

If I understand right, the focus control doesn't work. If so, then this could be your light output problem other than the reflector not in proper alignment after replacement.

I would definitely stay with the Christie lamp, since they tend to last longer than Osrams (with proper ventilation and such).

Posted by Sean McKinnon (Member # 612) on 01-16-2010, 02:28 PM:

You need to verify that your optical bench is in alignment after replacing the reflector. You want the center of the hole in the reflector, and the aperature of the lamphouse to be in alignment with the absolute center of the projector's aperature. They make kits with a lens barrell and string, or a laser device to align this. It is also possible to do it by eye but it takes skill and is not as accurate.

You also want to make sure that the reflector is the proper distance from the film gate. It should state in the H-20 manual what this distance is (ie: 34 inches or whatever)

Once you have your reflector the proper distance from the gate and your optical bench aligned you want to repair/replace the focusing mechanism so that you can align the lamp to the center of the reflector.

You should also make sure that the reflector is clean, and that the lamp is not blackened.

Another thing to check is if your power supply is operating at the correct current? If possible try to find someone with an "Amp Clamp" to confirm that the meter on your lamphouse is accurate.

Posted by Tony Bandiera Jr (Member # 2365) on 01-16-2010, 10:33 PM:

Your focus adjust problem is because the stupid snap ring Christie used for that has broken or fallen off...save yourself the future grief, remove that shaft, drill a small hole through it and use a washer and cotter pin. have a CH40 that I modified that way. It is easy to do.

Another thing to check is make sure the rear bulb support has the spacer installed..it is a trapezoid shaped piece the same thickness as the support plate, mounted between the support and the casting at the bottom where the four screws go.

If that spacer is missing you'll never get enough light out of that lamphouse.

And it is NLA from Christie. [Frown]

Posted by Louis Bornwasser (Member # 3063) on 01-16-2010, 10:38 PM:

We really don't know which of the reflectors he has: original Christie, Christie Phoenix kit, or the Super Lumex reflector that we developed back in 1980.

Especially if it is the last one, sometimes the number of spacers is wrong at the rear of the bulb which means that the bulb cannot reach proper focus. You should expect 95% of the light of a Super Lumex. Louis

Posted by Mark Gulbrandsen (Member # 72) on 01-17-2010, 02:16 PM:

Louis... If it's an H-20 lamphouse you can't install the Phoenix kit into it so says Christie... I disagree though. So if he has the latest replacement reflector for that lamphouse then he has the dicro version of the standard christie reflector. Thats about all thats available for them.

I agree with Tony. Check for a missing c-clip and repair it the way he suggests if that is indeed the problem.

Mark

Mark

Posted by Louis Bornwasser (Member # 3063) on 01-17-2010, 02:26 PM:

Don't change the bulb type.

If you have the know-how, the Hadden Super Lumex reflector kit will help a lot; triple or more light than from the Christie. Louis

Posted by Mark Gulbrandsen (Member # 72) on 01-17-2010, 02:28 PM:

Humm, Didn't Ringold originally design that retrofit?

Posted by Richard B. Perrine (Member # 409) on 01-18-2010, 10:02 AM:

In 1983-4, we took out our magnac's and put in a H-25 that Ringold sold us. Glenn Terrel did the job and told me he took a Strong reflector and designed the mount for it. He had the lamphouse out at his house for several months before we got it and put it in....don't know if that's ture or not....but if it is we got the first mirror made.
Thanks guys.

Posted by Louis Bornwasser (Member # 3063) on 01-18-2010, 05:58 PM:

I set up the original system for myself. I (at the time) didn't have enough demand to make the casting myself, so I tabled the idea. Glenn did the drawings of the bracket. Glenn, Ringold and Strong had a contract for the manufacture and distribution of said kit.

No money ever showed up at Ringold or Glenn Terrell. I was then asked (by Glenn) to make the kit myslf since he needed to buy 400 kits for National Amusements and he was unhappy with not being paid.

We install these to this day in Christie lamphouses (the smaller ones only.) Louis

Posted by Mark Gulbrandsen (Member # 72) on 01-18-2010, 06:04 PM:

It's interesting to hear the gestation of that kit Louis and I always wondered about it! I installed many of them back in the 80's and early 90s but none in a long time... I've also installed many Super Lum-Ex reflectors in Eprad Universals. A much easier job where you just have to enlarge the hole in the dividing wall to accomodate the reflector mounting ring.

P.S., I remember being at your shop a very long time ago and you showing me a Christie H40 that you had adapted the Kneisley metal reflector into.

Mark

Posted by Louis Bornwasser (Member # 3063) on 01-18-2010, 09:53 PM:

Never really worked out; mostly the customers for it bought Super 80's. Louis