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Topic: Reflector flaking

Don Sneed
Master Film Handler

Posts: 451
From: Texas City, TX, USA
Registered: Aug 2001

posted 11-09-2001 04:02 PM

I have consoles only a couple of weeks short of a year old, & the reflectors are flaking like gitter, the air flow is great, no problem there, any ideas why ???

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Brad Miller
Administrator

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

posted 11-09-2001 04:14 PM

Brand and model?

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 11-09-2001 06:11 PM

I've seen this numerous times. It can happen to any dichroic coated reflector. It has either gotten too much heat and it has caused the coating to delaminate and peel. It is only a molocule or two thick.
I have also seen batches of reflectors that had bad coating. They will also peel much the same way but may abruptly start to do it. This happened to both Strong and Kniesley in the past. Kniesley had this problem especially bad a number of years back. I'd check with the lamphouse manufacturer to see what they say. If its happenning on more than one lamphouse in a plex then I would tend to think that they might cover them under warranty. Its pretty obvious that somethings up out of the ordinary, especially if the air flow is real good.
Mark @ GTS

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Don Sneed
Master Film Handler

Posts: 451
From: Texas City, TX, USA
Registered: Aug 2001

posted 11-09-2001 08:56 PM

Thanks Mark, Good Idea....Brad it's a Strong Highlight II Console, 2K,& 3K, I seen this happen on old lamphouses, poor exhast, but less than a year old, any input from the Film-Tech Gods will help, Mark had a good idea.."call the manufacture"....I think I will !!

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John Pytlak
Film God

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

posted 11-09-2001 09:05 PM

Improper cleaning technique or materials might also damage the dichroic coatings, which I believe are multiple ultra-thin vacuum deposited metal and dielectric layers, and fairly fragile.

Here's a link to information on dichroic coating technology:
http://www.optiforms.com/coat.htm

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

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Gordon McLeod
Film God

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

posted 11-09-2001 09:14 PM

It can also be caused by the lamp set to far back in the reflector and causing a overheating of the area around the hole and it starts to spread
Also I found ORC lamps worse at causing it

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000

posted 11-12-2001 10:05 PM

I have a Christie 4500 watt console that is starting to do the same thing. Bulb focus and airflow is ok. The consoles are about 3 to 4 years old now, with the orginal mirrors.

Someone told me some time ago that some manufacturers had problems making "Cold" mirrors. I have seen a few of mine deteriorate, but not at an abnormally alarming rate like they did 10 to 20 years ago. I don't know how it is now, but 10 to 20 years ago, if the coating on a new mirror "fell apart" within 6 months or so, the manufacturer gratiously accepted it under warrenty.

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Pat Moore
Master Film Handler

Posts: 363

Registered: Mar 2000

posted 11-13-2001 10:23 AM

Don;

Improper cleaning is a likely culprit if you really have good air flow. Is it one or two systems in a complex, or all of them? If it's all of them, I'd really suspect the maintenance procedures.

All of us manufacturers have had occasional coating problems but they have been few and far between the last few years. If it's a warranty issue we'll certainly take care of it.

Pat

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Brad Miller
Administrator

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

posted 11-13-2001 02:30 PM

Hey Paul, I'm interested to know what kind of bulbs you are burning in those 4500 watt consoles.

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000

posted 11-13-2001 03:06 PM

Brad, we are burning Christies exclusively. I just "inherited" this booth to try and keep it running. It is in rough shape.

In other applications, I have had very good luck with Christie bulbs.

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Brad Miller
Administrator

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

posted 11-13-2001 03:23 PM

Interesting. I know of one specific theater with SLC consoles that has always ran Christie lamps and has never had a problem (it's at least 5 years old), but when they switched to ORC/PE lamps, the reflectors are flaking at the bottom where the bulbs are sagging.

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Don Sneed
Master Film Handler

Posts: 451
From: Texas City, TX, USA
Registered: Aug 2001

posted 11-13-2001 05:19 PM

Hey Pat, I called Troy today & he said the same thing you posted, I will check to see if all machines or just one...thanks for your input

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Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000

posted 11-13-2001 10:04 PM

Brad, the booth I inherited has been neglected very badly. To give you some example, 3000W lamps are being pushed to 120 amps. All the LED's in the basement readers are in such bad of shape that 3 of the units can't muster up enough video in SRD to keep it from defaulting, even with the power supplies two-blocked. The SDDS doesn't work, period! All the dash pots are either missing or just plain broken. One looks like it was cut out with a pair of wire cutters.

Got the picture? I don't think I really don't want any part of this booth to either work or repair, unless I am forced into it. It is a Christie booth.

Paul

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