Lifespan of a 65Q Socket

[joeb]

I've noticed quite a bit about this same problem when searching through posts, but couldn't necessarily find a post that asked this question specifically. How long should I expect a socket on an Altman 65Q to last? I know there are a lot of factors, but here are the basics.

We opened a new venue three years ago and it came with 14 Altman 65Q 6" Fresnels. The venue gets used very regularly, and the fresnels as part of the rep plot or a specific show, are probably on at close to full for an average of 20-30 hours a week, 45 weeks out of the year. After three years, I have six or so of these units whose socket has lost its "springiness" for lack of a better term causing them to arc and need to be replaced. Am I unreasonable thinking these sockets should last longer than three years? We have some older Altman 6" Fresnels - which I am assuming are 65Q's based on the fact that though cosmetically a little different, most parts seem interchangeable. After probably 25-30 years of use (not as heavy as they get now), these fresnels still have the original socket with no issues.

Another thought I had that might affect this is how they are hung. For the rep plot, they are hung on the first 2 electrics, used as front light for the back half of the stage, but they are typically used for top light focused straight down for theatre productions. Could being hung in this vertical position cause them to arc and lead to premature death on the socket's part? Any thoughts would be appreciated.

 

[jjsagona]

We have had a very similar experience - our facility is 7 years old and in that time, 8 of our 20 65Q Altman Fresnels have had arcing issues due to weakening sockets.

Joe, our use has been very similar to yours (front lights and lots of down spots), but I find it frustrating to believe that stage lights "won't work well when pointed down". Seems like a flawed implementation of the medium pre-focus base. I am currently going through and replacing those bases...here's hoping I have better luck!

 

[Les]

I would think that orientation has little to do with it, given the nature of the medium prefocus socket's design.

My first question is: What lamps are you using in these fixtures?

I have seen first hand that a well-used 65Q fresnel can be in service for 30 years without problems, but using incorrect lamps and long duty cycles (are these fixtures also used as worklights?) can take a toll on several parts within the 65Q - but usually the reflector is the first to go, with what I've seen.

Keep in mind that the 65Q is not rated for the BTR 1,000w lamp.

 

[joeb]

That was my thought with the prefocus base, but I didn't know if they had an inherently weak spring.

They have been lamped with both BTL's and, more recently, BTH's. They've never seen a 750, much less a 1k, lamp.

They are not used as work lights for any type of technical work, but they are used during rehearsals for dance, band, orchestra, and outside groups as our work lights are inadequate for these situations.

 

[mstaylor]

That is a fairly bullet proof fixture. Obviously long continuous use will shorten their lifespan but three years seems short. How often are you burning lamps out in the same time period?

 

[decoss]

Our community theater was given 12- 65Q's that were nearly unused. Right from the start the bases were giving us problems that were spring related. I found that by using
McMaster Carr #7437k15 electrical contact cleaner with lubricant (mega hat tip to Ship for this) the socket freed up and began working properly again.

I also had some correspondence with some engineers at Altman about this issue and they were of no help. They weren't even aware that this problem exists.

 

[decoss]

One more thing. We are using 500W lamps and have had none burn out on us yet.

 

[joeb]

decoss- Thanks for the tip on the cleaner/lubricant. I'll give that a shot. Would others recommend I use that on lamps that are seemingly good except for the fact that they arc'd in those fixtures, or should I just toss them?

As far as lamp life, those specific lights with the busted sockets would eat a lamp in a matter of minutes to a few days before I replaced them with some of the older inventory. The unaffected fresnels seem to have a typical lamp life. They get replaced once or twice a year, but that's under pretty heavy use.

 

[Les]

Remember that any fixture that has previously arced lamps will ruin the contacts of the new lamp until the center pin of the socket is replaced or refinished. Likewise, any lamp which has pitting as a result of arcing should never be installed in a good socket, or the good socket will shortly become a bad socket.

 

[pndoran_LD]

The auditorium I used to manage had the same issue with these fixtures (ours were less than 5 years old). As a temporary fix we stuck a piece of sheet metal on the center pin before inserting the lamp, this seemed to eliminate the arc issue caused by the weak springs. I spoke with several people at Altman, they claimed that their was nothing wrong with the fixture and that it was just normal wear and tear on the fixture (I found that odd, since I have fixtures dating back to the 70's with original sockets that still work just fine).

After several phone calls and a few emails with the president of Altman they sent me replacement sockets for all of my fixtures.

 

[ship]

The auditorium I used to manage had the same issue with these fixtures (ours were less than 5 years old). As a temporary fix we stuck a piece of sheet metal on the center pin before inserting the lamp, this seemed to eliminate the arc issue caused by the weak springs. I spoke with several people at Altman, they claimed that their was nothing wrong with the fixture and that it was just normal wear and tear on the fixture (I found that odd, since I have fixtures dating back to the 70's with original sockets that still work just fine).

After several phone calls and a few emails with the president of Altman they sent me replacement sockets for all of my fixtures.

A sheet metal spacer is a very dangerous thing to do - what if whle installing the lamp, that spacer goes off center and arch's to the socket?

Believe the first medium pre-focus type Fresnel sockets came out between 1936 and 1938. I have worked on a bunch of them over the years. Kudo's to Decoss noting what I even use on 5Kw Fresnels or movers, but that's assuming the socket is clean or resurfaced. Others in the past have recommedned a Kraig's De-Oxident that's copper filled for the same use - my experience, I stay away from such things as they gum up with heat - though I have not used this type.

So the first question I might ask about the lamp type is answered about wattage in me catching up. Next are you removing lamps between shows and installing them in different fixtures? What in failed condition do the sockets of your fixtures and lamps look like? Also what brand of lamp are you using? BTH obviously Osram, but in switching to them, cross switching and between fixtures?

Just as a moving light might get a lamp signature attributed to it good or bad, incandescent lamps also might.

Onto the meat of the observations... if you have weak springs, you don't get good contact to the center contact of the lamp. This will cause arching. Put a perfectly good lamp into a bad socket, you get another perfectly good lamp that fails in a shorter amount of time. On the other hand, put a crappy lamp into a perfectly good base and the solder might melt in causing the problem amongst other variables.

P-28s lamp socket is very rugged and can survive many re-surfacings of it. Have not found your issue, though I don't use 65Q's at work so it might be the case of stuck springs as with what my Wife complains often about in RSC springs sticking for cyc lights. Often the lube will free it up, but it's a problem for her even if contacts are good.

Springs can catch up on stuff and unless ensured to be freely operating will cause a problem. Ensure that your center contacts have not unscrewed themselves in being too loose, but other than that - lifespan of a P-28s socket is expinential but dependant on use and is possible that the newer ones are not as good as the older ones. I have not noticed this difference but I don't work on such gear actively these days other than for antique inventory.

Also cannot tell if something from Leviton, Bender & Wurth or Bule, much less Ushio amongst others would preform better. Would thing all will preform the same and rather focus that if there is a problem with a socket type, further lamp problems in doing so would be noted by way of flash light and inspection mirror of the socket. Not mentioned is if the socket even if springie was loose, what's the contact look like. Possible a springie contact but sufficient and a lamp problem if the base isn't arched also.