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Topic: Xenon Bulb Life Time

Christos Mitsakis
Expert Film Handler

Posts: 242
From: Ag.Paraskevi, ATHENS, GREECE
Registered: Sep 1999

posted 12-07-2005 11:10 AM

Marin,
In vertical configuration lamphouses the bulbs don't need rotation since the plasma burns steadier. Also from experience, a horizontal burning bulb doesn't need rotation if steady burning is acomplished by a well controled magnet. If the quartz begins to darken then rotation is needed and it is time also to check the magnetic stabilization.

Christos

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Monte L Fullmer
Film God

Posts: 8367
From: Nampa, Idaho, USA
Registered: Nov 2004

posted 12-07-2005 01:00 PM

Even with verticals - use the recommended changeout period listed with the bulbs.

Rotation isn't needed with the verticals.

Why bulbs get rotated is so the deposits doesn't gather on one place in the envelope, plus with bulbs in the horizontal position, the electrodes will sag over time is another reason to prevent this sagging with rotation.

Yet, some consoles cannot have their bulbs rotated - like the Christies due to the bulb's cathode end is a threaded pin (HTP) and the threaded end must be secure and fit snug to the collector nut that the pin threads into.

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John Pytlak
Film God

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

posted 12-08-2005 10:45 AM

quote: Monte L Fullmer
Yet, some consoles cannot have their bulbs rotated - like the Christies due to the bulb's cathode end is a threaded pin (HTP) and the threaded end must be secure and fit snug to the collector nut that the pin threads into.

For those who prefer to rotate lamps, don't some use a "spacer washer" that is just thick enough to have the lamp tighten into the cathode mount to rotate 180 degrees?

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Daryl C. W. O'Shea
Film God

Posts: 3977
From: Midland Ontario Canada (where Panavision & IMAX lenses come from)
Registered: Jun 2002

posted 12-08-2005 12:45 PM

Yes.

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Monte L Fullmer
Film God

Posts: 8367
From: Nampa, Idaho, USA
Registered: Nov 2004

posted 12-08-2005 02:21 PM

True, but the last time I did a HTP bulb the washers weren't included in the box and found out that bulb rotation for the HTP bulbs wasn't necessary since the insertion of the washer brought the focus to the aperture in tighter and most theatres weren't backing the bulb slightly to compensate for the slight forward placement of the bulb with the washer insertion.

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Louis Bornwasser
Film God

Posts: 4441
From: prospect ky usa
Registered: Mar 2005

posted 12-08-2005 04:31 PM

Osram no longer requires rotation for warranty purposes. I sometimes rotate anyway to extend the life. (3500 hours and am little darkening has occured...moves the darkening to another spot on the bulb.)

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Phil Blake
Jedi Master Film Handler

Posts: 558
From: esperance western australia
Registered: Nov 2003

posted 12-11-2005 12:35 AM

I have experienced the same as Louis Bornwasser stated , getting 4500 hours from 2K Osram . Light is still good at those hours , just lamp striking difficulties become a problem so we change at 4500hrs.

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Richard Hamilton
Phenomenal Film Handler

Posts: 1341
From: Evansville, Indiana
Registered: Jan 2000

posted 12-11-2005 05:25 AM

quote: Monte L Fullmer
True, but the last time I did a HTP bulb the washers weren't included in the box and found out that bulb rotation for the HTP bulbs wasn't necessary since the insertion of the washer brought the focus to the aperture in tighter and most theatres weren't backing the bulb slightly to compensate for the slight forward placement of the bulb with the washer insertion.

That doesn't make sense, just because people don't change the focus of the bulb, a bulb manufacturer suddenly says that it isn't necessary? That would be like a projector company saying "because people don't check the oil, it is no longer necesarry, just wait until the machine starts to act up, then change the oil".

If someone changes a bulb, but doesnt know how to check the light on the screen afterwards, they have no business changing bulbs. If they are too lazy, then they shouldn't even be in the booth.

Rick

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 12-11-2005 08:25 AM

You guys are only getting 4500 hours [Roll Eyes]

.... Not that I promote it but we have many customers that run their Christie Lamps past 10,000 hours... a few make 15,000 hours and these lamps come out clear but become hard to ignite! At one small plex in a smallish town I was the first tech to change lamps after the plex had been open for 7 years [Eek!]

. I've come to the conclusion that any other brand really is false economy.

Mark

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Steven J Hart
Master Film Handler

Posts: 282
From: WALES, ND, USA
Registered: Mar 2004

posted 12-13-2005 07:02 PM

quote: Mark Gulbrandsen
You guys are only getting 4500 hours .... Not that I promote it but we have many customers that run their Christie Lamps past 10,000 hours... a few make 15,000 hours and these lamps come out clear but become hard to ignite! At one small plex in a smallish town I was the first tech to change lamps after the plex had been open for 7 years . I've come to the conclusion that any other brand really is false economy.

Mark

Do you recomend Christie lamps for all brands of consoles and lamphouses, or do you get these great results from Christie bulbs installed in Christie equipment?
Steve

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Frank Dubrois
Jedi Master Film Handler

Posts: 896
From: Cleveland, OH
Registered: Mar 2005

posted 12-16-2005 01:34 PM

We use Christie and Strong lamphouses. No matter what watt bulb we use, 2000-4000, we seem to get mearly 2000 hours. I thought we were supposed to get close to 3200 on the 2000 watts, and about 1800 on the 4000 watt. I'm not one to run bulbs over 50% pas their warranty, however, with the 2000 watt bulbs, we basically get warranty life out of them before they get too dim.

What is the final word on rotating bulbs inside Christies? We also have the screw in type, and found the washers needed to rotate are only about $1. To me, its worth the $1, to my company, it apparently isnt. Do they know something I dont?? or would the $1 spent per washer be worth it in bulb hours??

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Louis Bornwasser
Film God

Posts: 4441
From: prospect ky usa
Registered: Mar 2005

posted 12-16-2005 01:40 PM

Osram does not require rotating. However, others may require it to activate warranty. The washer should not be needed on -htp bulbs, since you can loosen the clamp, unscrew what you need, then retighten. (Other Christie lamps use the nut supplied with the bulb so there is no problem in rotating.

Anything done to lengthen the useful life is probably worth it If in doubt, do the math: Cost divided by useful life= cost per hour. Louis

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Frank Dubrois
Jedi Master Film Handler

Posts: 896
From: Cleveland, OH
Registered: Mar 2005

posted 12-16-2005 06:44 PM

Well, I tried to get one washer ordered in able to show whether or not it would actually extend the life of our bulbs, but no good. Not needed aparently. Oh well.

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