Lamps burning out like crazy!

Joyce Thrift

New Member
I have a new position at a big (700 seat) 20 year-old High School theater and the lamps in my Strand Lekos and Zooms are burning out so fast! I spent most of the fall reorganizing the basic house lighting design and making sure everything was working, but by March many instruments already needed new lamps. Luckily, I started keeping track, so when I had more out in May, I found some of the same fixtures that got new lamps in March were burned out again in May. I swapped out the fixtures, but I'm wondering what would make the lamps burn out so quickly? Is there a fix? Could it be an electrical problem in certain addresses? Any advice would be welcomed. Thanks!
 
Make certain cleaning staff, administration and other faculty aren't turning the lights on for classes / cleaning / tour groups etc. and leaving the lights on after they go. Train them to turn off the lighting board when they leave.
 
I had a batch of lamps like that once. I guessed that they had been badly handled in shipping.
 
Any idea if this happend previous to your gig? Over voltage is good guess - but are your lamps 115 or 120, and did that change recently? 20 years ago could have been set up for 120.

Any utility work in the vicinity of the building?
 
I've heard that the previous staff also had a lot of trouble with lamps burning out. The lights are used for a lot of events, but they are not getting used for classes or left on all night. The board is turned off nightly. The lamps are FEL. So it seems like over-voltage could be it. Does this mean that some of my addresses are surging? Would I need to replace the dimmers associated with that address to fix the problem? Thanks for all the help so far.
 
If it's a certain batch of fixtures only, check the sockets and the dead lamps for oxidation, arcing, loose contacts.
 
Any instrument using an FEL lamp is an old one. Are the lamps really blown or do they come out with filaments intact? If they are intact, then the sockets are bad, which is a common problem with a unit of that vintage. A new lamp will work for awhile in a bad socket, until the socket arcs and burns the lamp pins enough for the connection to fail. I'll bet if you look closely, the pins on the dead lamps are burnt and pitted, not shiny.

The fix is to replace the sockets and put in NEW lamps. Do not put any used lamps in new sockets because the cancer will spread putting you right back where you started.
 
Agreed with @FMEng. I'd like to know a little more about these failed lamps. Are the filaments broken? Glass cloudy/discolored? Or do they look fine but just not work? I usually suspect worn out sockets above all else for unexplained, frequent lamp failures. Especially if the glass and filament looks fine otherwise. 10-15 year old sockets will be at the end of their life right about now.
 
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I have to agree with the above, check the sockets.

Also which fixtures are you using? How often are they put through a full maintenance cycle (cleaned and checked out)?

Ive seen various "models" of FEL some of which don't last as long. Not that the FEL is the greatest lamp ever. Sounds like they aren't from the same batch.
Which manufacture of FEL?

List of Strand fixtures that take an FEL as opposed to GLC or such:

Strand 2250/2240/2230/2220/2215
Strand 2204/2209/2211/2216/2111
Strand 2206 (Strand Lekolite)
Strand Cantata (various models)
 
Some of the lamps come out clearly burnt--gray, cloudy, maybe some bubbling. I'm careful about not touching the lamps, but I don't know what happened before I got there. Some others look OK and I will try to clean the contacts and replace them--this works occasionally. A few have broken off and I've had to pull out the base with pliers. I'm not sure of the model number, but I'll check that on Monday. I don't know how to do a "full maintenance" and I believe that I'm the most knowledgable person the school has hired in at least the past 8 years or so. Is there a good book or Youtube video I could watch and learn how to do it?
 
A few have broken off and I've had to pull out the base with pliers. I'm not sure of the model number, but I'll check that on Monday. I don't know how to do a "full maintenance" and I believe that I'm the most knowledgable person the school has hired in at least the past 8 years or so. Is there a good book or Youtube video I could watch and learn how to do it?

The lamp not coming out of the socket seems to be a fairly sure sign it has partially welded in, I assume there is some carbon (black marks) or such.
I would certainly replace the socket on these units.

I do not believe there is a video or anything (and I personally don't have any books that show this) showing how to do maintenance on THESE fixtures. They are indeed older. However perhaps someone else may be aware of something.
I however am familiar with all the fixtures I listed above, if at least a little.

At one venue where I do the bulk of my work we do a maintenance cycle on every fixture in the inventory once a year (in September, before the season starts).
I take them to the work bench backstage. Take them partway apart and use an air compressor and dry rag to remove all dust and debris (amazing how much can accumulate), occasionally further cleaning is required, but rarely. The whole time I am keeping an eye for broken or worn parts. Critical components are checked (socket, clamp, bolts, glass, reflector, shutters, other moving parts). I take my multimeter to the electrical contacts to make sure everything is good.
Anything deemed needing attention is fixed.
The fixture is put back together and its lamp put back in.
I plug it in to make sure it is working, and "bench focus" the fixture (adjusting the lamp position in the fixture for proper field and light output).
It is then sent back up to serve for another year.

You should be able to find a local tech who can show you what to do and how to do it.
 
Is there a good book or Youtube video I could watch and learn how to do it?
Not quite a book, but almost (and sorry no pictures). Some of the steps do not apply to your units, so feel free to skip over those. https://www.controlbooth.com/wiki/?title=Collaborative-Articles:Lighting-Fixture-Maintenance

See also this pdf http://www.etcconnect.com/uploadedFiles/Main_Site/Documents/Public/White_Papers/WP_Lamp_life.pdf , by another manufacturer but much is applicable to you.

In the end, the FEL is a first generation, short-life (300 hour) lamp. You could go to the GLE which lasts 5 times longer and uses 75% of the power, but only provides (17,400/28,000) = 62% of intensity.
 
Not really feasible to clean a G-9.5 lamp socket used on these lamps. Budget to replace most all lamps and lamp sockets. Once a lamp of this base type even starts to arc to a base, it's going to trash a new lamp base if installed into. No matter what the other crew might have done in touching lamps as described, it seems like you are also looking at everything but the obvious in caring for them when changing the lamps for why.

Changing lamps can be a science as to why it failed. Contacts look arched or is the lamp hard to remove (over normal for that base type), grey cloud etc. all have causes as with blackened globe or filament broken. Once known why the failed lamp has to be replaced it indicates fixture or location problems. Voltage spikes are somewhat reare for instance in not often a on-going problem.
 
Voltage at my facility reads 123 VAC. Sometimes it's 124. Power company says this is normal. How much will that effect lamp life?
IF you were actually providing 123V at the lamp socket, a 120V lamp would last 73% of its rated life.*
However, that's highly unlikely. Even today's most efficient dimmers will lose a couple of volts; voltage drop due to long cable runs will account for another couple of volts.
Put a twofer inline with the fixture, and, with the dimmer at full, measure the voltage at the unused female connector. If the voltage is truly above 120V, consider regulating the max output voltage at the dimmer; most modern dimmers have this feature.

*The attached Excel workbook tells the tale of input voltage and its effects on life, output, color temperature, etc. Your mileage may vary.
 

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The 1000W lamps in my school's colortran 5/50 Ellipsoidals also burn out quickly as well as our 1000W BTNs in our colortran fresnels. These are the lamps that have always been ordered here. This summer I am letting the maintenance department of the school know what lamps to order. What are some lamps that have similar output to or current FELs ans BTNs that will still work with these fixtures and provide a lamp longer life?

These fixtures have also probably not been cleaned or maintained properly in about 8 years. I am also going to suggest to our director and school that they should be properly cleaned this year and checked this year. What are some good starting resources for cleaning these fixtures?
 
What are some lamps that have similar output to or current FELs and BTNs that will still work with these fixtures and provide a lamp longer life?
Sadly, there are none. There are lamps with a higher efficacy, and lamps with a longer rated life, but none with the raw intensity/brute force that a 1000W lamp provides.
Thanks, ship. ...
So let me get this straight. It's brighter than a
BTL; 500W; 500 hour; 3000K; 11,000 lumens, LPW=22.0,
BTH; 575W; 300 hour; 3250K; 15,500 lumens, LPW=27.0,
but not as bright as a
BTN; 750W; 500 hour; 3000K; 17,000 lumens, LPW=22.7,
and no where close to a
BTR; 1000W; 250 hour; 3200K; 28,500 lumens, LPW=28.5,
???

Given the spherical reflector and purposefully diffused Fresnel lens, there's little to be gained from a lamp with a more compact filament design. ...

What are some good starting resources for cleaning these fixtures?
See post#14 above.
 

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