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Author Topic: What is the average life of a xenon bulb? Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 09-29-2003 10:24 PM                     The reason you get multiple striking is the no load voltage of many Kniesly PS's is too low for a lamp with a few hours on it THe ignitor will try to fire until the knowload voltage drops to the operating level kniesley make boost supply booster kits for there rectifiers to help  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 09-29-2003 11:00 PM                        quote: From a point of liability you guys all missed it. The life rating of a Xenon lamp is the manufacturers rated hours plus about 15% maximum. Past that you run it at your own risk ...thought that's what I said...  |  IP: Logged Paul G. Thompson The Weenie Man Posts: 4718 From: Mount Vernon WA USA Registered: Nov 2000 posted 09-29-2003 11:28 PM                     Brad said: quote: For what it's worth, I have never had the need to rotate a bulb in a Christie SLC lamphouse and I get ridiculous lifespan out of bulbs used in those units. I have experienced the same thing. Getting 6,000 hours out of a Christie bulb (even the 4000 watt lamp) in the Christie SLC seems to be a normal occurrence. Jack said: quote: Over and above all that, I have yet to rotate an otherwise perfectly fine bulb and NOT have it go unstable on me. Trying to wait it out... or jacking up the juice for a while has had inconsistent results. That's about the same way I look at it.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 09-29-2003 11:38 PM                        As others have noted, risk of catastrophic explosion increases as lamps are run well beyond their warranteed life -- lost shows and damaged lamphouse components cost alot more than replacing a lamp before it becomes "iffy". Likewise, unreliable ignition, flickering light output, and dim screens compromise presentation quality.  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 09-30-2003 12:24 AM                        I'm wondering what it is about the SLC that works so well with the bulbs... above-average filtering?... better cooling?... lack of reflections back to the bulb?... all the above? I do know for a fact that you can't get anywhere near 6000 good hours out of a 4kW bulb in an X-60 or Ultra 80, even with a switcher. Maybe you guys are just leaving these things on 24/7, eh?????  |  IP: Logged Dustin Mitchell Phenomenal Film Handler Posts: 1865 From: Mondovi, WI, USA Registered: Mar 2000 posted 09-30-2003 12:37 AM                     In the six years that I have worked at this theatre we have had one bulb explode. It was still under warranty. Bulbs should be changed when the envelope begins to show signs of age and/or the light it puts out is no longer at your presentation standards. I have run bulbs in Christie SLC lamphouses and Strong Super Lume-x's up to and over 4,000 with no visible signs of aging in the envelope and still putting 16fl on the screen (as measured by a light meter). I understand that in the early days of xenon bulb usage they tended to 'catastrophicaly fail' much more often than they do today. Things have changed apparantly (I wouldn't know since I haven't been in this business that long). Automaticaly changing bulbs at 125% of warranty is usually a waste of money, period.  |  IP: Logged Michael Schaffer "Where is the Boardwalk Hotel?" Posts: 4143 From: Boston, MA Registered: Apr 2002 posted 09-30-2003 01:40 AM                        quote: Right now I have slight darking on the underside of the lamp Misaligned stabilizing magnet?  |  IP: Logged Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 10-01-2003 12:45 PM                     Our projectors use 2kW or 1600W lamps and we run an average of three and a half shows a day. The lamps strike anew for each showing (not on all day). For lamp wear calculations, I use 2 hours as some movies are longer and some are shorter. In one day, (3.5 showings x 2 hours) + 3.5 strikes = 10.5 hours. In 30 days that's 315 hours and in 6 months we're at 1890 hours, so I try to change all of the lamps in April (in time for summer releases) and October (just before Thanksgiving/Christmas). Oh my! I guess this means I'm due! We've had some premature bulb deaths but we have been using PerkinElmer lamps and quite a few Film-Techers have no faith in PE for this reason. I'm going to switch to Christie or Ushio for this next set of changes. Aren't Christie and Ushio "one and the same" ? [ 10-01-2003, 08:38 PM: Message edited by: Manny Knowles ]  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 10-01-2003 06:02 PM                        The lamphouse (or at least the cooling provided by the lamphouse) seems to make a big difference in lamp life. I've gotten 4000 hours out of several 2kw Osram bulbs in Strong Highlight IIs; the same bulbs would barely go for 2000 hours before starting to flicker in Christie H20s. At most theatres, bulbs usually get changed when they start to flicker or when they're obviously old (3500-4000 hours for 2kw; less for larger bulbs). Changeover houses should replace both bulbs at the same time. I've personally seen one explosion (presumably a defective bulb) and have heard about one depressurization (bulb was 15 years old with a few hundred hours; there was no noise, but the screen went dark and the bulb wouldn't re-strike). I also know of one lamphouse where 3kw bulbs only seem to last about 600 hours before either flickering badly or turning almost completely black. For the most part, though, bulbs just start to flicker and get dimmer as they age. Related question: how many spare bulbs do you keep on hand? Obviously, every theatre should have at least one new spare of every type of bulb that is in use, but how important is it to keep more than one?  |  IP: Logged Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 10-01-2003 07:54 PM                    A small theatre on a tight budget can probably get by with keeping a few old bulbs that were removed in good working order as spares rather than tying up a lot of cash on the shelf. But obviously at least one new spare is preferred.  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 10-01-2003 08:24 PM                        I have one 7kW system... I keep one new lamp and one used spare. I have 3 4kW systems, two in one location and one in the other. There's one new spare at that place, plus one used. At the location with two, the usage is very even, so I keep two new bulbs and two used spares. Of the 3 2kW systems I have in one location, I keep two new lamps & two used spares. I don't really know why I keep the used bulbs... guess if all hell broke loose, I'd have replacements onhand for everything. Lamp replacements occur between 6 & 12 months, so we don't really keep a lot of long-term stock onhand. The 4 & 7kW lamps will eventually be running in the same model lamphouse. Once that's done, I'll keep a replacement reflector in stock (it's a glass dichroic). The smaller lamps are all metal Super Lume-X, so it doesn't seem to me that keeping a spare in the booth is that critical.  |  IP: Logged Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 10-01-2003 08:36 PM                     If a lamp looks good when I remove it I will keep it as an emergency spare. I have several like that by now and I rarely have to use them. I keep about 2 of each type on hand brand-new. Those are the real spares. As I mentioned, sometimes they have failed prematurely -- even right out of the box. This is where having a few "good used" spares comes in handy. Having said that, I would not advise keeping the used ones as the main spares. I know of a theatre that did this -- and may still be doing it. Basically, if a lamp died or started acting up they would change it out with one of the used ones and wait for a new bulb to arrive. The reason I don't like this approach is that it means someone has to change a lamp twice. Not only is this double work, it also doubles the risk for possible injury during the change-out.  |  IP: Logged Aaron Sisemore Flaming Ribs beat Reeses Peanut Butter Cups any day! Posts: 3061 From: Rockwall TX USA Registered: Sep 1999 posted 10-01-2003 11:27 PM                     quote: Aren't Christie and Ushio "one and the same" ? Yes, except for the name engraved into the ends of the bulbs. Ushio is the parent company of Christie. There is another bulb that looks very similar to a Christie/Ushio bulb, these are the 'Yumex' brand bulbs (designed by former Ushio engineers, thus the similarity) . I have tried a few in the past, and they were OK... Better than ORC/PerkinElmer and Chinese bulbs, but not as good as 'real' Christies or Osrams. -Aaron  |  IP: Logged

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