Head Problems.

[PARchild]

Recently, our theatre has had a rash of non-working heads for our Lekos. With a limited amount of fixtures and a rapidly dwindling supply of working heads, I am in dire need of some advice for fixing them. I've tested all of our cables and aside from a few twofers, all of them are operational. We just installed a new dimmer rack and it undergoes it's daily check for operation. So aside from the amateur who wired our rack and switched dimmers around (dimmer one is now seventeen) all of thew dimmers are operational. The lamps we use work in the currently operational heads, so I've ruled out bad lamps. I've done all checks I know to rule out everything but a bad head. We cant afford to buy new ones and my TD and ATD simply do not have the time to tech me how to fix them. As the head lighting technician for my school I am the one who gets the flack at showtime when they expect everything to be operational. I've exhausted that avenue of help so I've come here as a last ditch effort. The school is demanding a full stage wash setup and we simply do not have enough fixtures to light everything without all the heads being operational. Since all I know about our heads is how to change the bulb and fix the stage pin connectors I am in desperate need of advice. When I find a head with a lamp in it nine times out of ten one of the prongs(?) is charred. They are 2-pin lamps. Does anybody have any advice to what I may do to fix the problem?

[icewolf08]

It is time to replace your lamp bases (the little porcelain piece with the contacts). You can get them from any dealer, just tell them what type of fixture you need lamp bases for. If you tell us what fixture, we can also tell you what base you need. On most fixtures it isn't a particularly difficult install, but we would need to know what fixtures you have to give instructions.

Also, you should check your working fixtures for evidence of lamp base deterioration. If you have bases that are going bad it will ruin lamps. You should avoid putting new lamps in fixtures with bad bases as it is like a virus and will just spread.

[xander]

Icewolf is right. Old Altman lekos go through lamp bases really quickly. The good part is that they are fairly cheap and easy to install. I don't know what type of instruments you have but a new porcelain only costs about $12 or so for 360Qs. Once you get new parts if there isn't anyone at your school to help you install them, I am sure someone here will help you.

Repeating what icewolf said: don't keep putting new lamps in the bad bases because the corrosion will just build up on the lamp pins and then they will be more likely not to work in a good base.

Good luck,
Tim

[gafftaper]

What's is the brand, model, and age of the offending instruments?

[Grog12]

1st: Its cap or base.
2nd: Shine a flashlight down into the porclain base mentioned before. Is it nice and copper/brass looking? That's a good thing. If its black and charred follow Ice's advice. Porcelins are cheaper than full caps/bases.
3rd: If you have never changed out a porcelin before please GET HELP DOING IT. No matter what the light is (unless its a PAR64) there are many little bits and pieces that can get lost in the shuffle when disasembling the cap of a ERS.

[derekleffew]

Originally Posted by Grog12

1st: Its cap or base.
2nd: ...the porclain base mentioned before. ... Porcelins are cheaper than full caps/bases.
3rd: If you have never changed out a porcelin before ...

Actually, it is either "socket," or "lamp burner assembly." "Lamp cap" is acceptable for the entire unit; but "base" is a part of the lamp. "Porcelain" is a slang term applicable only to an Extended Mogul End Prong socket in a PARcan.

"Head" is used to describe the portion of the luminaire containing the light source, to differentiate from the head cable and ballast. Most often used when describing HMI fixtures used for TV/Film.

I will never forget an ME saying to me, once we had relamped a 360Q during focus "DId you guys forget to replace the cap gasket? Why is all that light coming out of the *rear* of that fixture?" (The cap gasket WAS in place, but was not seated correctly.)

[Grog12]

Originally Posted by derekleffew

Actually, it is either "socket," or "lamp burner assembly." "Lamp cap" is acceptable for the entire unit; but "base" is a part of the lamp. "Porcelain" is a slang term applicable only to an Extended Mogul End Prong socket in a PARcan.

"Head" is used to describe the portion of the luminaire containing the light source, to differentiate from the head cable and ballast. Most often used when describing HMI fixtures used for TV/Film.

I will never forget an ME saying to me, once we had relamped a 360Q during focus "DId you guys forget to replace the cap gasket? Why is all that light coming out of the *rear* of that fixture?" (The cap gasket WAS in place, but was not seated correctly.)

Porcelain has also come to be used in reference to S4's as the actual socket with in the lamp burner assembly is made of porcelain. Replacing them sucks.

[derekleffew]

If you say so. Did they teach you that in college? Technically it's ceramic, not porcelain. http://www.controlbooth.com/forums/l...porcelain.html. Kids today!

[PARchild]

I apologize for my vagueness. The heads I am talking about come off of 360q Altman's. I've been working in the school for about four or five years (I dont keep track) and we have never done any sort of maintenance on them aside from cleaning the lenses and reflectors. Our ATD tried to solve the problem once with a wire bristle brush but it yielded no results.

[Grog12]

Two can play that game sir http://mail.altmanltg.com/publicsynergy/docs/BDBinDoc.asp?Id={417D02D3-3FD4-4B46-BBC5-C26D1EF80524} Mogul end prong socket anyone? http://www.bmisupply.com/bmicat/bmic...%20Catalog.pdf And porcelin is a form of ceramic sir. Enough of the pissing match what was this thread about in the first place?