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Author Topic: Uneven output between xenon lamphouses Hillary Charles Jedi Master Film Handler Posts: 748 From: York, PA, USA Registered: Feb 2001 posted 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? Thank you in advance.  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 12-12-2012 09:34 PM                        What happens if you swap the reflectors?  |  IP: Logged Hillary Charles Jedi Master Film Handler Posts: 748 From: York, PA, USA Registered: Feb 2001 posted 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?  |  IP: Logged Hillary Charles Jedi Master Film Handler Posts: 748 From: York, PA, USA Registered: Feb 2001 posted 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.  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 12-13-2012 01:00 PM                        Barring alignment issues (varies from one lamphouse to another) you will find the reflector to be the problem.  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 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).  |  IP: Logged Hillary Charles Jedi Master Film Handler Posts: 748 From: York, PA, USA Registered: Feb 2001 posted 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?  |  IP: Logged Paul H. Rayton Expert Film Handler Posts: 210 From: Los Angeles, CA , USA Registered: Aug 2003 posted 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.  |  IP: Logged Hillary Charles Jedi Master Film Handler Posts: 748 From: York, PA, USA Registered: Feb 2001 posted 12-13-2012 07:13 PM                     Thank you, Paul. We'll keep that place in mind!  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 12-13-2012 07:43 PM                        I think Optiforms is metal reflectors. I think the old Kneisley is glass. Call them early. Louis  |  IP: Logged Hillary Charles Jedi Master Film Handler Posts: 748 From: York, PA, USA Registered: Feb 2001 posted 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).  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 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.  |  IP: Logged Hillary Charles Jedi Master Film Handler Posts: 748 From: York, PA, USA Registered: Feb 2001 posted 12-14-2012 03:37 PM                     Email sent, Tony.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 12-15-2012 11:24 AM                     If memory serves those reflectors were made by Toledo Glass and had a dichroic coating  |  IP: Logged Hillary Charles Jedi Master Film Handler Posts: 748 From: York, PA, USA Registered: Feb 2001 posted 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... 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.  |  IP: Logged

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