# elephantitus bubbles on globe



## ship (Dec 11, 2007)

Recently had a lamp out of a Mac 2K fixture. Had a blob on its globe one might expect came from someone touching the lamp. This lamp however had over 900 hours on it and was on tour so unlikely anyone had opened the fixture and touched the lamp since it had been installed. Also it's unlikely that such a blob/bubble on a lamp globe could surve that many hours without blowing.

Turns out the lamp installed in the fixture right before this one was the first lamp ever installed in the fixture and it also had the very same problem, except that the blob on the globe exploded after 860 hours.

If this bubble on the globe was not from touching the lamp, and there was a signifigant amount of time within the fixture it took to develop, what might be the causes of such a thing?

I'll attempt to take and post a photo tomorrow.


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## gafftapegreenia (Dec 11, 2007)

I'm thinking lubrication from the moving parts somehow got onto the lamp. Either a leak or someone did a bad job lubricating the fixture. My other thought was maybe somehow fog or haze condensed on the lamp.


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## Charc (Dec 11, 2007)

Perhaps the MAC 2K wandered away from a leper colony?


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## avkid (Dec 11, 2007)

That's not the correct name for the disease, it's elephantiasis.


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## soundman (Dec 11, 2007)

Knowing little about the causes of lamp failure and even less about the specifics of arc lamps I'll give logic a try, The only fact we know for certain is that one fixture has had two lamps fail in the same manner. In a smaller rental house it might be possible for those lamps to be from the same batch and that might be something to look into. Judging by Ships previous posts Philips drops off MSR lamps by the skid so I am going to move on to other causes. My gut tells me the problem lies in one of three places, the lamp power supply (or ballast), the igniter board or in the optics. 

I figure if the lamp isn't getting the power it wants the arc will be off and that could cause some weird issues, if the optics are off they could add some heat to the lamp which would not be good but I don't think it would be able to cause it to turn molten.


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## ship (Dec 11, 2007)

I don't use Phillips lamps in these fixtures but overall very close to my thinking having discounted the dirt blown in concept - while a valid concept and possibility. Reason for this is it was one of many fixtures on the rig, yet the only one with this problem.

Logic soundman is getting you very close to my thinking - experience or not, well done.

Not the same batch, and while my batches are 100 per month of this lamp type, such a batch problem would be more common given over a thousand dealt with per year. These as avkid says elephantiasis cases while I see them more frequently than most are not all that common. 

But you did catch an important point, in that a new fixture, second lamp ever installed into it, both got up beyond their expected lamp life but not beyond their often same lamp in a fixture 1,200 to 1,500 hour very feasible and common lamp life while on tour. Both in tracking the lamps developed the same fault in this specific fixture as opposed to what happens in other fixtures more normally.

On the other hand, power supply and voltage problems have different symptoms than this in lamp failure. What are the common symptoms of this?

What than is left as the potential problem with Mac 2K 169 Wash that those on the tour should potentially check out before lamp #3 potentially fails from the same problem?


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## ship (Dec 11, 2007)

Just checked the lamp in question - took it home for adding to the future annex to the wall of shame. 994 hours which is above the 860 hours the last lamp had a blow out after but given the same condition. A member of the forum Inkie 2 replaced the lamp last month but unfortunately under "reason for replacement" line on the replacement lamp box tag they have to fill out amongst other lines in me tracking the lamps, he just wrote in "deformed." Not why he had reason to open up the fixture and note this trait which I can easily also see such as with a "snowball" lamp, just "deformed" instead of something like dim or brown as description of why this fixture was not outputting like the others. Not a lot of help in studying or coming up with trends. Still I did send him an E-Mail about the fixture to check it for the ____ suspected cause of failure. 

On a similar Mac 2K note, recently did a re-lamping for a tour and a debate came up between my boss and I. Lamps on this tour all are in the 1,200 hour range but some look really good. The tour person was asking if he should take some of these still good lamps and place them into fixtures on the floor and or easily gotten at should they develop problems. My boss in seeing price and random chance was for one position, I was for another out of a specific reason these lamps look good now but would not in the second fixture - this beyond lamp tracking problems on my end.

Why did I recommend against attempting to install what seemed perfectly good lamps into other fixtures for a few hundred more hours? This given all were well beyond their expected lamp life but in some conditions could still eek out a few hundred more hours reasonably given a 1,500 hour norm often? What conditions in my point of view would be necessary to eek out those few hundred more hours? Why would I feel that if installed into different fixtures would such lamps no longer be safe or even live up to a theorized maximum lamp life above what the listed lamp life is? This again given that lamps at 1,200 hours which still look good can often live up to 1,500 or beyond lamp hours. Specific reason for this is requested.

Than of course, in the same respect how can a lamp that looks brown in one fixture look perfectly fine in another fixture? This given a lamp under expected lamp life of the lamp, what about a lamp after that expected lamp life in the above would make me not want to put the lamps into new fixtures? This or make me expect that even perfectly fine lamps would not dependably work in the new fixtures in this instance?


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## ship (Dec 12, 2007)

lamp photo in question


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## soundman (Dec 12, 2007)

Sagging and blackening, any idea what came first? would the blackening go away when the lamp is struck? I get the feeling gas is involved. I can't pin point it but heat is obviously involved because the glass has changed shape.


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## sloop (Dec 12, 2007)

I wonder if there is a defect in the reflector... A reflection hotspot right back on the lamp would increase the heat by a huge amount. That is a pretty symmetrical bulge..


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