Lights and Sound: single filament lamp failure

single filament lamp failure

Printed From: Community Theater Green Room
Category: Producing Theater
Forum Name: Lights and Sound
Forum Discription: Technical discussion
URL: http://www.communitytheater.org/forum/forum_posts.asp?TID=4149
Printed Date: 1/19/25 at 8:56pm
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Topic: single filament lamp failure

Posted By: David McCall
Subject: single filament lamp failure
Date Posted: 7/29/09 at 5:01pm

I just had 3 GLA lamps fail in a row. They failed while focusing the fixture.
The first one might be excusable because I did jar the fixture, but I was
trying to be careful when the other 2 failed.

These all had a single large filament. I just read that the orientation of this
filament matters. It is important to orient the lamp so that the support is
above the filament, otherwise the filament can fail by bumping the
support and shorting out. This was news to me.

GLAs are available in a concentrated filament design (multiple filaments
on a rack). Are these more resistant to shock? There is a brighter lamp
known as a GLC but the rated life is substantially shorter. Someone
suggested that the GLC was more reliable.

Does anyone have anything to offer on this subject?

David

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David M

Replies:

Posted By: Gaafa
Date Posted: 8/01/09 at 9:53pm

The problem might be with the latern, it's self, rather than lamps. I'm sure you would have tried another latern unit, with same type lamp bubbles - it may be something as simple, if you have not had the problem before?

This site may help:-

http://www.donsbulbs.com/cgi-bin/r/t.pl/failures.html - http://www.donsbulbs.com/cgi-bin/r/t.pl/failures.html

Have you checked with your Lamp Distributor, they could have had this problem with this brand before?

The only problem I have experianced before, is when a young TIT [Techie In Training] was found to be changing the bubble & not using a condom, when handling it. But from your post, I doubt this would be a problem & usualy it will work untill the glass envelope becomes pregnant 'n pops out. {Funny how the lamp never does seam to ever spawn an offspring globe either?]

As for filament reinforcement, unlike the old incandecent "T' series lamps, although they had a lot of element rack reinforcement, when they became hot, they were very delicate & tended to sag as well over time. With the inert gas filled bubbles, I have never had that same type problem.

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Joe
Western Gondawandaland
turn right @ Perth.
Hear the light & see the sound.
Toi Toi Toi Chookas {{"chook [chicken] it is"}
May you always play
to a full house}