|
|
Author
|
Topic: Life Expectancy of Rarely Used Bulbs?
|
|
|
|
|
Randy Stankey
Film God
Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99
|
posted 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.
| IP: Logged
|
|
|
|
Leo Enticknap
Film God
Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000
|
posted 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.
| IP: Logged
|
|
|
|
|
All times are Central (GMT -6:00)
|
|
Powered by Infopop Corporation
UBB.classicTM
6.3.1.2
The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion
and agrees to release the authors from any and all liability.
|