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This topic comprises 4 pages: 1 2 3 4
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Author
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Topic: HELP!! Black and blue bulbs
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John Pytlak
Film God
Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000
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posted 09-29-2000 12:06 PM
Sylvania/Osram published a very good xenon lamp troubleshooting chart, with photos showing lamps that failed for different reasons. It was republished in the February 1996 issue of Kodak's Film Notes for Reel People (H-50-38).If the lamps are turning totally black or clouded, it may be due to "operational air infiltration" caused by a crack in the graded seal typically caused by an overheated connector base. If the metal connector base is also discolored, this overheating is the most likely cause. Lesser blackening may have a variety of causes, including poor operational current (ripple), improper magnetic stabilization, or improper forced cooling. If you are returning the lamps under warrantee, OSRAM will usually examine the failed bulbs. If there is a problem in your operation, they will deny the warrantee and tell you the possible causes and remedies. ------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment 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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Bruce McGee
Phenomenal Film Handler
Posts: 1776
From: Asheville, NC USA... Nowhere in Particular.
Registered: Aug 1999
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posted 09-29-2000 12:21 PM
"Improper forced cooling..."Maybe the fans are clogged or the motor is slow due to lack of oil? How about corrosion around the base causing a lack of heat conduction away from the lamp? In the case of threaded lamp bases, would heat sink compound on the threads help at all? Just a question. I have not done it, yet.
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John Pytlak
Film God
Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000
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posted 09-29-2000 12:30 PM
Bruce:
Although heat sink compound will provide better thermal conduction between the base and mount, I'm not sure it will help increase electrical conductivity and reduce oxidation/corrosion of the contacts. There are compounds sold to use on electrical connections (e.g., for aluminum-to-copper connections), but I doubt that they would withstand the heat without vaporizing and causing other problems. Best advice is probably simply to maintain clean and tight connections without additional materials being used.------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment 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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John Walsh
Film God
Posts: 2490
From: Connecticut, USA, Earth, Milky Way
Registered: Oct 1999
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posted 09-29-2000 11:15 PM
I would look at cooling, also.Just a note; the model "Maxi-10" refers to the automation controller, which can be mounted in a variety of Xetron lamp consoles. It is not the model of the lamphouse/console. If it's a console, it's probably their "XCN" series lamp consoles. If so, what serial number is it? Serial no.s 3384 and onwards had an improved cooling method. I think this lamp has a screw base; if so, is it being screwed in tightly? (you use the clear plastic cover as a tool to tighten the bulb.) If it an older XH-x000 series, they didn't cool very well. Many years ago, Xetron put their name on Cinemecannica/Zenith lamps.
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Pat Moore
Master Film Handler
Posts: 363
Registered: Mar 2000
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posted 09-30-2000 06:25 AM
This does sound like cooling issues, something is doing a slow cook of a lamp seal. 1600W lamps aren't really that hot so something else is happening here.When you say they are going to a blue-black color, are you talking about the quartz vessel or the metal end fitting(s) on the bulb? If it's an end fitting, wich one? Are the reflectors silver in color, or a yellow and/or bluish tint? The tinted ones are "cold" reflectors, dichroic coated to absorb heat energy of the lamp output and still reflect the light. If you lightly brush the surface of the reflector with a soft cloth, does the coating come off, producing little "sparklies"? If they are silver, there may be an in-line heat filter to reduce heat energy getting to the film. It passes light and reflects the energy. It (or they) should be mounted at an angle so the energy isn't thrown directly back onto the bulb & reflector. The xetron design uses two rectangular filters side-by-side, if I remember right. Most of my experience was with the larger lamps and not 1600W. Can you verify the amperage the lamp is running at? The meter might be off and you're running hotter han you think. Cooling -- is there any air directed at the anode (positive)? What's different about this one lamphouse? Is there a lot of operation with the dowser closed? Does it feel hotter than its mates in the booth? Check the position of the reflector and its working distance in relation to the film plane -- is it the same as the others? Pat
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Don Sneed
Master Film Handler
Posts: 451
From: Texas City, TX, USA
Registered: Aug 2001
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posted 01-14-2002 05:58 PM
I can't agree with the improper cooling, I think a bad batch of bulbs, I just installed a 1600 watt bulb in a Strong consoles that date back to 1985, the exhaust was 400CFM, the blowers are cooling over the bulb as design, corrections are tight, rectifier is ok, & after 7-hrs the bulb turned black, put in another that & the same thing happen again after 300 hrs, install a old bulb with 3300 hrs on it and no problem, we remove this old bulb in the 1st place due to the hrs on it, but after no more spares we re-installed it, that has been 200 hrs ago & still going good.....so I can't agree with poor cooling, I think bad bulbs !!! well that's my two cents worth....
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they black, or blue out, causing them to slowly die until there is hardly any light making it to the screen. The reason this puzzles me is because everything seems to be within nominal ranges. I am running a OSRAM Xenon 1600W bulb. When I start things up readings are great. between 68 - 70 amps, and 18 - 20 volts. Right within specs. So why am I losing bulbs right at or around 300 hours? All connections to the bulb are tight, the bulb is focused on screen, I am truly baffled at this one! Any help would be greatly appreciated. 
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