Conventional Fixtures Lamps blowing constantly, all of a sudden

X

xander

Well-Known Member
I'm running into a very confusing problem. The venue is brand new and opened before it was done. What this means is that the problem really could be anywhere because none of the systems have even been tested. But regardless, here we are with three operating theaters and construction still going on.

My current issue is that I have about nine mini-10 fixtures being used as house lights that keep blowing lamps. They worked fine for a week of tech and a week of previews. At the beginning of this week (second week of previews) they started blowing. I replaced the lamps in three and when I turned them on, they blew immediately. I replaced two more and they worked. Of the nine, only two have not had an issue, yet. Some I have replaced the lamp and they have worked since. Some I've replaced twice and still don't work. Some just don't work and I've run out of replacement lamps. Basically, I only ever have four or five working because when I fix one, a different one goes out 15 minutes later.

I'm not sure the make of the fixture, but it is pretty crappy quality. They are not like any other mini-10 I have ever used. They take a FAD lamp (650W/120V). They are cabled and circuited to the same dimmers as the rest of the rig (Sensor+ racks) and nothing in the show is having an issue. I've metered the circuit at the fixture at a solid 115V. I've pretty much ruled out dimmer or cabling as the problem.

I feel like it has to be a heat issue. The internal wiring or socket has been damaged by 2 weeks of overheating and now they are just blowing everything...

Any input would be appreciated.

Thanks,
-Tim
 
What does the filament look like. Is it burned through?
Is the glass envelope clear or darkened. Does it bulge.
If you look at the ends of a bad lamp - are the contacts pitted or clean?
 
avkid said:
Did all the lamps come from the same place?
Click to expand...
The ones I replaced today did all come from the same place, but the ones that were put in the fixtures at installation, I cannot say.

JChenault said:
What does the filament look like. Is it burned through?
Is the glass envelope clear or darkened. Does it bulge.
If you look at the ends of a bad lamp - are the contacts pitted or clean?
Click to expand...
One bad lamp was clearly blown, black envelope. The rest have looked absolutely fine. No discoloration. Filament looks intact. Envelope fine. Contacts look clean on the one I have in front of me, couldn't say for the rest.


Thanks,
-Tim
 
WOW I just did some reading and found that the life of these lamps is only a 100 hours!!!!!!!
 
Last edited:
xander said:
The rest have looked absolutely fine. No discoloration. Filament looks intact. Envelope fine. Contacts look clean on the one I have in front of me, couldn't say for the rest.
Click to expand...


Sounds like a bad weld between the lamp crimp and the pin in the base of the lamp. Usually, one of the wires is thin and serves as a fuse link. Since the lamps look fine I suspect there was a run of them with bad welds.
 
So the consensus being that the original lamps just met the end of their lives (7 lamps within 2 use hours of each other) and then the lamps I replaced were just a bad batch?
 
xander said:
So the consensus being that the original lamps just met the end of their lives (7 lamps within 2 use hours of each other) and then the lamps I replaced were just a bad batch?
Click to expand...

:rolleyes:100 hour lamp in a house light. Time to go back to the people who specified this nonesense because regardless of whether the second batch is bad or good you are going to need a huge budget for house lamp replacement. The issue to be addressed is what can be installed as a replacement house light and who screwed up and gets to pay for it?
 
Agreed with church. Otherwise, you will have to work something out where the house lights are always dimmed, underdriven, and therefore, will last longer. Because our houselights will be very difficult to change, I've programmed the Lumanet system so that the houselights can only be run up to 90%. I figure 90% is probably still high enough to support the halogen cycle, yet low enough to extend life. If worst comes to worst, that is something you may consider. Still, that should be a last resort. Like church said, go back to the folks that were involved in the decision to specify or purchase your houselights and see what they will do for you.
 
I would be looking at one of the 400 hour options and run them at 95% to help lamp life. You'll lose way to much output with the 2000 hour lamp options.
 
This is not your problem to solve. The building should be under warranty, so the responsible party is the general contractor. There's a chain of command, starting with the general. He will go to his electrical sub, the architect, and the architect's consultants as needed to find a solution. Have the owner's representative put it on the GC's punch list.
 
What do you want to bet the EC had a bunch of these laying around and used that advantage to put in the low bid?
 
Nelson said:
Agreed with church. Otherwise, you will have to work something out where the house lights are always dimmed, underdriven, and therefore, will last longer. Because our houselights will be very difficult to change, I've programmed the Lumanet system so that the houselights can only be run up to 90%. I figure 90% is probably still high enough to support the halogen cycle, yet low enough to extend life. If worst comes to worst, that is something you may consider. Still, that should be a last resort. Like church said, go back to the folks that were involved in the decision to specify or purchase your houselights and see what they will do for you.
Click to expand...

We do this exact same thing and it makes a huge difference to lamp life. I highly recommend it and I doubt that the difference between full and 90% will make a difference to your audiences.
 
Whether or not there is a fix or work-a-round, is not the point. The fixture is wrong for the intended purpose and who ever specified it should be held liable for the replacement.

A $ 10.00 lamp every 100 hours vs. a suitable LED replacement offering 50,000+ hours would be hard to turn down. And that doesn't even account for the difference in energy usage with the FAD consuming 650w per hour vs. 100w. Slightly more than a kilowatt of savings every two hours.
 
DrPinto said:
I just found the L&E "Cranny Flood". This strangely named instrument does list the FAD as an option.

http://www.le-us.com/sitebuildercontent/sitebuilderfiles/6360.pdf

Is this what you have?
Click to expand...

BillESC said:
Whether or not there is a fix or work-a-round, is not the point. The fixture is wrong for the intended purpose and who ever specified it should be held liable for the replacement.

A $ 10.00 lamp every 100 hours vs. a suitable LED replacement offering 50,000+ hours would be hard to turn down. And that doesn't even account for the difference in energy usage with the FAD consuming 650w per hour vs. 100w. Slightly more than a kilowatt of savings every two hours.
Click to expand...

I think its more an issue of incorrect lamp choice, not incorrect fixture choice. Not everyone is willing to go with the more modern LED fixtures, and the up-front cost might make them prohibitive for the use intended. I have seen plenty of places with this sort of fixture as house lights, they just use different lamps that last a mite longer than 100 hours.
 
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