Film-Tech Forum ARCHIVE: Life Expectancy of Rarely Used Bulbs?

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Posted by Chris Rasmussen (Member # 3015) on 10-19-2011, 01:08 PM:

Greetings,

I'm a tech for a small, high end, twin projector screening facility that uses 35mm irregularly. The CXL-20R bulbs have roughly 355 hours apiece since 2007.

I change bulbs in pairs to keep the light as even as possible and hope that some of you out there have experience with rarely used bulbs. What constitutes "old" in bulbs that aren't approaching their hours - is it an issue?

Thanks,

Chris ~

Posted by Monte L Fullmer (Member # 2797) on 10-19-2011, 01:40 PM:

355 hrs on them ... still babies for Christie 20R bulbs.

You must be running STRONG X-90 consoles.

Keep them in there and if a layer of dust gets on them, clean with denatured alcohol.

...and you really don't have to change in pairs since no two bulbs are alike. That's in a way, throwing money out the window doing that, for 20R bulbs have a good 2000hr warranty on them.

You go by how it looks on the screen and focus accordingly when needed. If the light looks dull, is then a changeout would be needed.

Posted by Randy Stankey (Member # 64) on 10-19-2011, 03:34 PM:

I have used three xenon lamps in my projector in 15 years.

The first one was an ORC, installed in 1996.
It lasted almost 1800 hours before it started getting hard to strike.

The second one was a Superior Quartz, installed in 2003.
It lasted about the same number of hours before it started getting hard to strike.

The current lamp is a Christie CXL-20R, the same as yours.
It is only the third lamp in almost 15 years. It was installed in June, 2010 and only has 180 hours on it. It's still burning strong. I don't even think about it. The thing just works.

Every spring, when the school year lets out, I do a complete cleaning and preventative maintenance on the projector. The only thing I ever do to the lamp is dust out the lamphouse with a vacuum cleaner and a clean, white cloth. That's it.

Considering my experience, I don't think you'll have any trouble with your lamps. [thumbsup]

Posted by Mark Gulbrandsen (Member # 72) on 10-19-2011, 03:40 PM:

I have customers that have run that lamp for over 20K hours... [Eek!]

Posted by Randy Stankey (Member # 64) on 10-19-2011, 05:07 PM:

I probably could have nursed the second (SQP) lamp along until 2,000 hours or more. The lamp was clear. No black. The electrodes were a bit worn but noting I haven't dealth with before. It just took two or three cracks before it struck. Sometimes, you had to hit the manual strike button. If you pre-struck the lamp, let it burn for a minute to get warm it would fire up the second time without any problems.

I had an opportunity to get two new Christies so I figured it was easier to just change the lamp and be done with it than to tinker with the existing lamp just to squeeze a few more hours out of it.

Now, the ORC was a different story. The glass was starting to get black and it was getting really difficult to strike. You had to lay on the button several times before it would light. At 1,800 hours, it was tired. I, pretty much, had to change that one.

I often have Work Study students running shows with me and they tend to get panicky if things don't behave predictably the first time. There are a few who learn how to troubleshoot but 75% of them are there just because they get to watch movies for free. I'm happy just to pre-thread the projector for them and let them just push the button and focus the picture.

If it was me working alone or with a knowledgeable crew, I'd have no problem pushing a xenon lamp until they completely stopped working but, given my circumstance, seven years on a lamp is a pretty good record.

Posted by Monte L Fullmer (Member # 2797) on 10-19-2011, 05:21 PM:

quote: Randy Stankey
Now, the ORC was a different story.

..the many horror stories that I can tell about ORC/Perkin Elmer bulbs ... and do agree: they could never reach warranty hours without hard strikes and being black.

Old LTI's were the same - never could get warranty out of them. But, it looks like Philips have turned that company around after taking over LTI.

Christie CXL-20R's are the best for this application.

Posted by Randy Stankey (Member # 64) on 10-19-2011, 06:22 PM:

Superior Quartz weren't no slouch, either. It's just because there was extra money in the budget at the end of the academic year that had to be spent or else it would be lost. I was told "Buy everything you could possibly need."

The SQP was still running but, as I said, it often had to be nursed to get it to light. I certainly could have nursed it for another year. Maybe longer.

But, when the bean counters tell you to buy now or forever hold your peace, you buy.

Posted by Leo Enticknap (Member # 534) on 10-23-2011, 10:05 AM:

quote: Mark Gulbrandsen
I have customers that have run that lamp for over 20K hours...

About two years after I left the theatre biz full-time (this would be '03 or '04), I got a call from a lady who ran an arts centre type place up on the Moors. It was a multi-purpose venue: live gigs, theatre, poetry readings, that sort of stuff, with film screenings once or twice a week. They were on a shoestring budget and had occasionally called us asking for pro bono help at the cinema in York I worked at from 99-01. Most of their staff, including the bloke who did the projection (retired accountant and home movie buff), were volunteers. The problem this time was that the lamp in one of the projectors would not strike without a fight, and once alight, was dim and flickery.

The projectors in question were two GK-37s of 1960s vintage with original lamphouses and rectifiers, and a Heath Robinson (US: Rube Goldberg)-style audio system consisting mainly of consumer hifi equalisers and amplifiers.

My first thought was rectifier diodes. Alarm bells rang when I arrived, however, because when I asked for the face mask, jacket and gloves to open up the basement, there then followed an hour-long search in the cellar to find them. No one at the venue had opened up the lamphouses within living memory, which meant the mid-1970s. Upon doing so, the envelope of the bulb was so blackened you couldn't even see the cathode or anode inside it, and there was actual rust formation on the caps and flylead of the bulb! To the best of everyone's knowledge there, those two bulbs had been in operation for 35-37 years without being touched. The lamphouses didn't even have hour counters on them, so it's anyone's guess how many hours they'd done.

We replaced the bulb and the diodes in both lamphouses for measure, and not only was the problem sorted but everyone was staggered at how bright and sharp the picture looked.

I haven't had any contact with the place since, and would be very surprised if it was still running film.

Posted by Richard P. May (Member # 3598) on 10-23-2011, 11:03 AM:

We have been using the same pair of bulbs in a lab screening room for the last five years. They now have close to 2000 hours, running at 1000 w.
Some days maybe 3 or 4 hours use, but more often much less, checking prints as they come off of processing. It is important that the brightness (16fl) and color temp are even between the two projectors.
Christie bulbs in Strong lamphouses.
There has been no sign of change in the light quality.

Posted by Tony Bandiera Jr (Member # 2365) on 10-23-2011, 02:15 PM:

The CXL 16's at UC Irvine (see the pics in the warehouse, UC Irvine HIB100) are now 14 years old, have just over 900 hours on them and are still going strong. They still strike on the first hit and are steady from cold start.

In general, I feel confident in saying that any bulb by Christie, Ushio (who makes Christie's bulbs) or Osram should have an almost indefinite "shelf life" and can be trusted to run to at least the warranty hours. Any brands I didn't mention either suck and I wouldn't trust to last 10 minutes (ORC, Perkins-Elmer, the chinese knockoffs) or are manufacturers too new to say how they will hold up.