This is topic Uneven output between xenon lamphouses in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Hillary Charles (Member # 769) on 12-12-2012, 07:31 PM:
This is sort of a follow-up to a previous question regarding our 500W Kneisley L-100 (actually one is rebadged as an A.V.E. but is pretty much the same) lamphouses. By slightly altering the amperage and defocusing the brighter lamp, we were able to put on a decent show. However, now that we have the luxury of time, we'd like to get to the bottom of the problem.
Here's what the units look like:
One unit appears to be working fine. The light is bright and white. The projected image has great color and contrast. The other unit produces a duller picture, with a slightly bluish cast. The picture lacks that snappy contrast of the other.
We have switched the lamphouses between projectors & power supplies, and then we switched the bulbs. In every case, the problem was in the same lamphouse, REGARDLESS of the power supply and REGARDLESS of the bulb. Both bulbs perform perfectly in the "good" lamphouse, and both perform poorly in the "bad" lamphouse.
Now, what is wrong with that lamphouse? ![[Confused]](confused.gif)
Thank you in advance.
Posted by Scott Norwood (Member # 30) on 12-12-2012, 09:34 PM:
What happens if you swap the reflectors?
Posted by Hillary Charles (Member # 769) on 12-12-2012, 10:39 PM:
Excellent question, Scott! We figured on some feedback here before getting into that, but we're starting to wonder if that is a factor.
The lamps performed evenly when we got them 12 years ago, and as we look at the reflectors, the "bad" lamphouse appears to have the better reflector. However, we've noticed recently that when lit, the ambient light we see through the ventilation louvers from the "bad" lamphouse has a pinkish hue, while the ambient light from the "good" lamphouse is bluish.
Is it possible the silvering has degraded enough in the one reflector to create this problem?
Posted by Hillary Charles (Member # 769) on 12-13-2012, 12:51 PM:
Here is the visual aid to what I described in my previous post. For all intents, the lamphouses are functionally identical, so the difference in ambient light between these makes us wonder if it's connected to the difference of light on the screen. We'll switch out the reflectors as soon as we can to see if there is any change. Until then, all suggestions are welcome.
Posted by Louis Bornwasser (Member # 3063) on 12-13-2012, 01:00 PM:
Barring alignment issues (varies from one lamphouse to another) you will find the reflector to be the problem.
Posted by Scott Norwood (Member # 30) on 12-13-2012, 01:25 PM:
The reason why I thought of this is that I am fighting this issue in two venues, both of which are two-projector changeover houses with Super Lume-X lamphouses. In one, the roof exhaust blower failed and several shows were run without it--this caused the reflectors to flake, which strangely happened at different rates. Now, one lamp cannot be aligned completely and is slightly dimmer than the other. In the other venue, used equipment was installed and the reflectors were of different color temperatures. This is a real issue when running B&W films, and I hope that the owner will spring for new reflectors before our next screening (in February).
Posted by Hillary Charles (Member # 769) on 12-13-2012, 01:30 PM:
Interesting. We hadn't done anything physically to the lamphouses over the years other than changing bulbs. Scott, I think you sent us a couple 500W bulbs, and both are working great.
The silvering on the "bad" reflector actually looks to be in better condition than on the other one. However, if the reflector turns out to be the problem, I guess it's worthwhile to have it (or both) resilvered. Is that service still available?
Posted by Paul H. Rayton (Member # 1817) on 12-13-2012, 02:33 PM:
Reflectors CAN be re-silvered. The one company with which I'm acquainted is down near San Diego, CA. Optiforms, Inc. (website: http://www.optiforms.com/ ) can be a good contact for such work. They will provide quotes, and, from talking with them, it sounds like the price will be much more reasonable if it is for a reflector for which they have previously done production work. But, failing that, they can coat apparently most anything. Sales rep is Michelle Langland, m.langland@optiforms.com, tel 951-296-1300, x. 125. BTW, there is an interesting "tech vault" page at their website having to do with methods of cleaning reflectors, which may be of interest.
Posted by Hillary Charles (Member # 769) on 12-13-2012, 07:13 PM:
Thank you, Paul. We'll keep that place in mind!
Posted by Louis Bornwasser (Member # 3063) on 12-13-2012, 07:43 PM:
I think Optiforms is metal reflectors. I think the old Kneisley is glass. Call them early. Louis
Posted by Hillary Charles (Member # 769) on 12-14-2012, 08:53 AM:
The idea of coating is academic now. When we removed the "bad" reflector, we noticed a crack. It is all but invisible when installed, but obviously not worth spending money on. Best to try to find a replacement (reflector or lamphouse).
Posted by Tony Bandiera Jr (Member # 2365) on 12-14-2012, 11:53 AM:
Hillary, Contact me by email or PM..I will have a pair of relatively clean LP Assoc. 8510 Lamphouses and 8501 (120v) magnetic rectifiers being pulled from a screening room next month. We can discuss price and shipping off of the forum.
ANYTHING, even ORC (can't believe I said that) would be better than the Kniesley firetraps.
Posted by Hillary Charles (Member # 769) on 12-14-2012, 03:37 PM:
Email sent, Tony. ![[Smile]](smile.gif)
Posted by Gordon McLeod (Member # 33) on 12-15-2012, 11:24 AM:
If memory serves those reflectors were made by Toledo Glass and had a dichroic coating
Posted by Hillary Charles (Member # 769) on 12-15-2012, 04:29 PM:
The coating definitely looks like it's dichroic. We did our final, and seemingly conclusive test today by exchanging those reflectors, and the problem did indeed follow the reflector.
Gordon, I wonder if Toledo Glass could still make them... ![[Wink]](wink.gif)
Tony, I wouldn't mind upgrading. Right now, we have two good 500W bulbs in service and two good back-ups, and if it is at all possible, our best option would be to find a replacement reflector or parts unit with a good reflector. Thank you for the email. We'll be writing back tonight.
Posted by Martin Murray (Member # 162) on 12-16-2012, 01:29 AM:
Hillary, I have several Kniesley reflectors that I will never use again. If you want one for free e-mail me just pay shipping.
Posted by Hillary Charles (Member # 769) on 12-16-2012, 10:00 AM:
Hi Martin,
I wasn't able to send you an email, so I sent you a PM. Thanks!
Hillary
Posted by Gordon McLeod (Member # 33) on 12-16-2012, 10:30 AM:
As a side note that lamphouse had an interesting history as it origianlly used a phillips sealed beam xenon lamp that had been designed for the norelco FP16 compact lamphouse
Posted by Hillary Charles (Member # 769) on 01-12-2013, 10:04 AM:
Hi Martin,
I emailed you with photos and dimensions of the reflectors a few weeks ago, but haven't heard anything yet. Please let me know if you didn't receive that info and I can post it here if that works better. Thank you for your offer. I hope you can find something that works.
Hillary
Posted by Jay Glaus (Member # 6011) on 02-03-2013, 02:39 AM:
I know I'm a little tardy to the party, but if anyone needs one I have a reflector out of a 3k big sky lamphouse that I would be looking to get rid of for a few bucks. I only had it in for a few years, still in great shape. We were playing around seeing if a different reflector gave us any different results and they were both about even so we had an extra. Just a heads up!
Jay
Posted by Hillary Charles (Member # 769) on 02-08-2013, 01:57 PM:
Hi Jay, I sent you a PM. Thanks!
Posted by John Eickhof (Member # 323) on 02-11-2013, 03:58 PM:
Hi Hillary, I used to service many of the 'pup' lamps in screening rooms, we had a difficult time getting reflectors to match color temp. The early ones used a one piece osram lamp & reflector, they were pretty good. I doubt you will be able to find any reflectors, but if you do, I am looking for two of them also. Good luck.
Posted by Gordon McLeod (Member # 33) on 02-16-2013, 01:24 AM:
just to note that is not the pup lamphouse the pup used the same 14" reflector as a xenex 1 the unit pictured used originally a phillips sealed beam lamp and was latter retrofited when the lamp was discontinued with a seperate reflector made by toledo glass
Posted by Louis Bornwasser (Member # 3063) on 02-16-2013, 07:59 AM:
Gordon; this is the unitized bulb/reflector that at one time was sent in "prealigned," right? Smaller refector (5 inch)?
Posted by System Notices (Member # 2357) on 11-12-2014, 07:24 AM:
It has been 633 days since the last post.
Posted by Hillary Charles (Member # 769) on 11-12-2014, 07:24 AM:
Miracles DO happen! We found a pair of NOS reflectors!
The only issue we have now is that in replacing the bad reflector, the small, presumably asbestos pads at each mounting point pretty much tore apart. Before we run with these, we'd like to make replace these with something equally effective at buffering the heat expansion as well has handling the heat itself.
Here is a photo of the one of the reflectors in its mount, as well as the old, cracked one.
Does anyone have any ideas for satisfactory replacement pads? As usual, thanks in advance!
Posted by Donald Brown (Member # 5427) on 11-12-2014, 08:05 PM:
Hillary:
Perhaps you could obtain a sheet of fiberglass cloth and cut equivalent pads. A good hardware store will likely have this product in stock.
I fashioned a number of aprons from this material for a carbon arc operation to catch carbon splatter and limit the degradation of the reflectors, so there is no question that it will withstand the heat. There was no adverse impact on the glass either.
Don Brown