Film-Tech Forum ARCHIVE: Xenon bulb ever seen this happen?

This is topic Xenon bulb ever seen this happen? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Cameron Glendinning (Member # 3516) on 02-03-2007, 08:24 PM:

Well I've never seen that before in my 20 years! Does this sort of thing happen often? This Osram 2500w was pulled after 1200 hours in our vertical lamphouse.

Posted by Tim Reed (Member # 137) on 02-03-2007, 10:35 PM:

Is that the new igniter-less bulb? You strike them carbon-arc-style. [Razz]

Seriously, though, I don't think I've ever seen that happen.

Posted by Monte L Fullmer (Member # 2797) on 02-04-2007, 03:36 AM:

..bet the rectifier had fits with this one ... and just HOPE that OSRAM gives you credit for that interesting bulb on warranty exchange.

Posted by John Wilson (Member # 269) on 02-04-2007, 04:26 AM:

quote:
Is that the new igniter-less bulb? You strike them carbon-arc-style. [Razz] [Wink]

You'll soot the mirror keeping them that close Cameron.

Posted by Frank Angel (Member # 248) on 02-04-2007, 05:42 AM:

As some one on a ratings board once said, I can't define pornography, but I know it when I see it. Well, this looks WAY to close to pornography if you ask me. I bet the second these two hotties get together, sparks fly!

Posted by Gordon McLeod (Member # 33) on 02-04-2007, 09:09 AM:

Has the anode actually detached itself from the stem or did it detach up in the seal area

Posted by Marin Zorica (Member # 1716) on 02-04-2007, 10:30 AM:

Yes strange thing!

Newer saw something near like that...

Can You post a picture of anode and cathode ends...?

Posted by Cameron Glendinning (Member # 3516) on 02-04-2007, 05:02 PM:

Widest shot I have

Gordon, At this stage I do not know what caused it or where it is broken. Just in a little shocked that it happened. I suspect that it detached up at the power input, as there are no signs of visible damage in the glass envelope section.

Tim, John & Frank, thanks for your witty replies [Big Grin]

I guess its my fault for not adjusting the trim!

Posted by Louis Bornwasser (Member # 3063) on 02-04-2007, 07:18 PM:

New bulb? Have seen this once. Bulb was dropped on end. Those parts are press fit. My electrode detached from the "stalk". Louis

Posted by Cameron Glendinning (Member # 3516) on 02-04-2007, 08:51 PM:

Louis, that bulb was working perfectly until 1340 hours, when 1/2 way through a screening, the light went out. The projectionist on duty was spooked that dispite no light, the rectifier was outputing 80 amps. The bulb was changed and the show went on.

Posted by Jack Ondracek (Member # 1466) on 02-04-2007, 09:16 PM:

quote: Cameron Glendinning
The projectionist on duty was spooked that dispite no light, the rectifier was outputing 80 amps.

OK... up until now, I was almost convinced this was an early April fools Photoshop.

Just wondering... is that a switching supply you have?

Looking at that picture, I wondered why a rectifier wouldn't have blown its own hole between those electrodes, but I guess a switcher would limit itself (?). If yours held at 80, you were probably lucky.

Posted by Jonathan Worthing (Member # 803) on 02-05-2007, 06:42 AM:

Yes i have seen this.

The chance is the joint between the cable in the end cap has come unattached from the anode bar (can not be seen as it is covered by the end cap). This can happen due to a shock, but
more than likely it is a manufacture fault.

I have seen it with new lamps, I had a 5KW do it years ago. [scream]

It is as scary as hell to see the anode sliding about in the middle of the lamp bashing in to the cathode.

Posted by Cameron Glendinning (Member # 3516) on 02-06-2007, 02:45 AM:

Jack I could believe that you thought it a joke, I found the telephone call at the time very sureal! Did not mention it here until I took the photo

quote: Jack Ondracek
Just wondering... is that a switching supply you have?

The Rectifier is a 1972 vintage National xenon silicon rectifier from Gaumont Kalee, its huge and heavy.

Jonathan, I'm glad it was my day off when it happened! Thankyou for letting us know that we were not the only ones. Seems pretty rare though, perhaps I should buy a lottery ticket.

Posted by Jack Ondracek (Member # 1466) on 02-06-2007, 03:12 PM:

quote: Cameron Glendinning
The Rectifier is a 1972 vintage National xenon silicon rectifier from Gaumont Kalee, its huge and heavy.

A converted arc rectifer, maybe? With a ballast resistor to limit current?

Posted by Cameron Glendinning (Member # 3516) on 02-07-2007, 02:53 AM:

I would say so Jack, The word xenon is added in a different style on a different colour background, its huge and has its own exaust. Its a long way from the small black boxes that you can carry today!

mmm I replaced the other cinemas bulb, It was in for 17 months and 7244 hours, which is pretty impressive to me. Thats when I realised that the other bulb had only been in for for 7 weeks. I cheaked the figures and found a pretty obvious mistake, the bulb had only done 920 hours, so back to Osram she goes.

[ 02-08-2007, 09:26 PM: Message edited by: Cameron Glendinning ]