Conventional Fixtures - Altman 6" Fresnel Lamp Base Problems

[bwhiteford]

Hey CB Users!

This is an awesome forum, so glad to be here. Question for you:

The theater i'm working in has a bunch of 6" Altman Fresnels, all in great shape physically. However, the issue i'm having trouble with is that many of them seem to have an issue with the lamp socket.

The instruments use 750w BTN lamps, and i've tried both new and old lamps. The lamps don't seem to fit tightly. I push it down, turn it 90 degrees, and it stays, but wiggles in place. As a result, the lamp flickers, you can hear the sound of a loose electrical connection at the base, and the fixtures work intermittently.

Do these bases wear out eventually? The fixtures are fairly old (late 80's, early 90's).

Thanks so much for your help in advance, see if we can get these things running again!

Thanks,
Brooks

[xander]

Yes, the lamp socket will wear out. And from the sound of it, yours have. Inside the socket there is a spring (which is what you press down when inserting the lamp) and it sounds like it is worn out, so it isn't able to press the lamp upward and make the connection. It is a very simple and fairly cheap process to change the lamp base.

-Tim

[gafftaper]

You have a different problem, but the same solution as Lieperjp is having in this thread. Check it out for information on replacement.

[derekleffew]

bwhiteford, your Altman 65Q fresnels (if that's what they are), use a medium prefocus socket (P28s base), unlike Lieperjp's 8" Fresnels which use the larger, rarer, and much more expensive, mogul prefocus socket.

Medium prefocus sockets are widely available for around $15.00.

[SteveB]

bwhiteford, your Altman 65Q fresnels (if that's what they are), use a medium prefocus socket (P28s base), unlike Lieperjp's 8" Fresnels which use the larger, rarer, and much more expensive, mogul prefocus socket.

Medium prefocus sockets are widely available for around $15.00.

And if you are unfortunate enough to be using the so-called 1kw rated fresnel, the 1K6FR, replacing the socket is a royal pain the you know what.

Never again with Altman !.

SB

[bhallerm]

I had the "fun" of replacing 20 of those last fall. All of our fresnels had sockets that were corroded and would blow the lamp quickly. After I lost three lamps in one day I said "enough". I paid $38 a piece to have my lighting guy fix them. You do the math for my budget hit. I will say that they have all worked great since then, just a pain to have to do that. Still cheaper than replacing all 20 fixtures at once.

BJH

[Les]

Don't forget to use the same rule that applies for bi-pin lamps. Don't put lamps that have already been "contaminated" by the bad sockets into your new sockets. Otherwise you will spread the disease!

[bwhiteford]

You guys are great, thanks for the input. I'm going to order a few and see how it works out. I'll let you know what comes out of it!

[gafftapegreenia]

1K6FR's hate life, it's pretty simple.

I got at least a half dozen needing bases.

[ship]

Again with the resurfacing concept off the 75Q 8" Fresnel post.

What's a 1K6FR? Never heard of such a beast..



While inside the light fixture there will be other stuff to be checking. Given the heat damage, other stuff could be in need of service due to heat or age and use.

[derekleffew]

...What's a 1K6FR? Never heard of such a beast. ...

Altman 1KAF-MPF or 1KAF-MBP. 1000W, cast Aluminum, 6" Fresnel, with either a medium prefocus or medium bipost socket.

[SteveB]

Altman 1KAF-MPF or 1KAF-MBP. 1000W, cast Aluminum, 6" Fresnel, with either a medium prefocus or medium bipost socket.

I think that Altman changed the designation at some point from what I knew as the 1K6FR to what Derek shows us.

My designation is 1KAF-MPF-POS

My bad for not checking.

SB

[joefader]

bwhiteford, your Altman 65Q fresnels (if that's what they are), use a medium prefocus socket (P28s base), unlike Lieperjp's 8" Fresnels which use the larger, rarer, and much more expensive, mogul prefocus socket.

Medium prefocus sockets are widely available for around $15.00.

Could you provide a link to where to buy such a socket? I am in need of one.

[techieman33]

You should be able to buy a new socket from any of your normal theatrical suppliers.

[gafftapegreenia]

Should mention that I have started rebuilding all my 65Q with Medium Bi Post sockets. Takes a bit of work (making a template, drilling and tapping the reflector sled, re routing the wires), but I am full time staff so I have the time. But the benefits are no more arcing and around 1,800 more lumens with the EGR.

Switching a 1KAF to the MBP socket is probably easier, as Altman actually sells that fixture with a G22 socket.

[ship]

A shame that if full time staff that you don't spend shorter time in repairing old 90% of the time repairable lamp sockets to work again at about as much time and like 10% the cost or less. Written extensively on this over the years in detail about this specific lamp base, the G-22 also wears out as with new P-28s sockets. Might be able to save a G-22 socket but saving a bad P-28s socket is normally fairly easy to do in not even having to take apart much to re-surface the base.

This in saving money and expending just as much time in installing a new socket for something that could with a bit of work make the socket as good as new almost in possibly lasting just as long.

Note: pay attention to the bad lamp that was installed in that bad socket as it's just as bad as the base. Same concepts in restoring the used lamp contacts that was in the fixture noted in the past, or if not also buying new lamps for the new socket you will quickly also get another bad lamp socket. So in the above, double your money and throw out everything in costs to fix it, or just the right silicone fiber and wire wheels with a Dremmel and some electrical contact cleaner to fix the problem and not waste time in re-drilling for the new lamp socket.

[gafftapegreenia]

And ship, that is exactly how I expected you would feel about my choice.

I certainly did consider resurfacing, but the center contacts are BAD, with about half so badly pitted that there is no hope. I tried it on a few and had to grind down the center contact by at least half of its original thickness. This was coupled with the fact that for new sockets I was looking at having to drill my sleds anyway, as most of my inventory is for the older socket mounting pattern. Then, adding in the fact that I am also completely rewiring them, ultimately it wasn't much more labor to switch socket types.

But I actually think its all moot now. I saw the HPL in 65Q at USITT. I didn't think it would work nearly as well as it does, its really quite nice. Hopefully Altman will have a retrofit kit soon.