P28S and BTR, Out of the Box Thinking

[Ken Johnson]

As promised, here are three photographs of the base of a new Osram BTR lamp. I have not attached an image to a post before and hope I have done it reasonably well.

Pictures 1 and 2 are of the same lamp. Picture 3 is of a second lamp from the same case.

Here is picture 2.

Lastly, picture 3

As I have stated before, it is my contention that these irregular surfaces will not make a good contact with the terminal in the socket.

As far as a resolution is concerned, I am not sure what else I can do. If nothing else, I have pointed out what I consider to be an issue. Where it goes from here is beyond me. If I do try something, success or failure, I will report it.

Thank you
Ken

 

[SteveB]

I'm questioning whether this is a socket problem or a over-heating problem in the fixtures.

I really hate bad mouthing a manufacturer, but the Altman 1KAF fresnel is a piece of you know what. I have had the same issues with sockets while running 1kw lamps and finally down rated my inventory of 48 fixtures to 500 watts. As well, with the 1kw lamps, the lenses can fail and I've always wondered how this fixture got UL listing for this lamp wattage. When I complained to Altman about cracked lenses, they shipped me about 200 small squares of what I assume is Fibertex or some such, to retrofit between the lens and the metal holder. Really ?, that's your solutions ?.

As comparison, I have had about 15 years use out of a Colortran 6" 1kw rated fresnel with neither lens nor socket issues while using BTR's of assorted manufacturers.

Sorry Altman.

 

[Les]

I'm questioning whether this is a socket problem or a over-heating problem in the fixtures.

I really hate bad mouthing a manufacturer, but the Altman 1KAF fresnel is a piece of you know what. I have had the same issues with sockets while running 1kw lamps and finally down rated my inventory of 48 fixtures to 500 watts. As well, with the 1kw lamps, the lenses can fail and I've always wondered how this fixture got UL listing for this lamp wattage. When I complained to Altman about cracked lenses, they shipped me about 200 small squares of what I assume is Fibertex or some such, to retrofit between the lens and the metal holder. Really ?, that's your solutions ?.

As comparison, I have had about 15 years use out of a Colortran 6" 1kw rated fresnel with neither lens nor socket issues while using BTR's of assorted manufacturers.

Sorry Altman.

I believe that the lamps pictured are brand-new (correct me of I'm wrong). I've never been fond of the 1KAF series either, but most of my frustrations centered around the focus slide, which on some fixtures, would need baling wire to hold the lever at the flood position. They didn't all have this issue, so maybe it was an adjustment (or lack thereof) problem. This was in high school and bought new when I was a Freshman (2001 or so), so they had been on the market a while. We didn't have any lens failures.

However, I did experience the lens failures at a community theatre who had bought their 1KAF's in about 1995. Apparently there was a recall on the units and the fix was the squares you mention. IIRC, it wasn't necessarily an issue of too much heat, but that the heat was transferring from the metal casing to the lenses too readily, too quickly, or too something. The insulating pads did apparently solve the problem.

Interestingly, I never noticed them eating lamps too often either, which leads me to believe that somewhere along the line there was a change in supplier of the lamp socket.

 

[Ken Johnson]

Les, the lamps are brand new.

Concerning the Altman instrument. These have been in service for about three years. There have been no problems with either the lenses or focus slides. I understand that earlier versions of some instruments had problems. If it were not for the current problem, everybody would be really happy with the Altmans.

As I pointed out in my initial posting, Altman does not manufacture either the sockets or the lamps. My gripe is that I find this socket/lamp interface to be questionable. If you use this family of lamps, what else can Altman install?

SteveB, what, if anything, is different in your Colortran instruments? Do your sockets look like the current version, do they have the same type/shape of contact? You say you are using BTRs, are these recently purchased; do they have the same contact shown in my pictures? If not, what do they look like and who makes them. I would love to find out why your old instruments work and our new ones do not. You MAY have the key to the problem.

Ken

 

[SteveB]

Ken,

I've never researched the why with the Colortrans, just the issues with the Altmans.

As well, the 12 C-Trans we own are currently in use and I've no access for a month or so, so cannot give you a timely reply.

The C-Tran is a very slightly larger unit and I believe not cast aluminum, as is the Altman, so possibly that's part of the difference. As well I would suspect the Colortran has better convection cooling.

I'd forgotten as well, the Altman problems with the focus handle as described by others. The damned things frequently slip their spot/flood setting and tightening the nut on the bottom of the fixture does not solve this problem.

Then there's what I call "brown edge" where the fixture at full flood has a somewhat unexpectedly medium soft brown edge, which I had otherwise never seen in a fresnel. Almost makes you want diffusion.

Note that my fixtures are now 20 years old, so possibly there have been improvements to the model but I was so fed up with the problems that I refused to buy more and am slowly not fixing and relegating to the trash.

 

[PeteEngel]

The P-28 socket has been used for a long time and I don't know why it is still around. I've never had a good experience with the socket/lamp combo. If you need these units for a show you will have to deal with them as they are. My suggestion would be to replace the sockets with a different type (gx9.5 or other). Work with Altman to find an acceptable solution that works with that unit. Your other option is to scrap them all and go with something new. yeah, I know this may not be financially possible but between the two options... Don't start down the road of "how can I modify this...", it doesn't really end well in either the short or long term, for the most part. If there is someone to look at for this, find out who specified the P-28 socket model.

 

[ship]

Sorry, not understanding any comparisons in the above. 14" scoop is a E-39/40 base screw socket lamp and open faced fixture. The 1KALF is an enclosed Leko or Fresnel rated for 1Kw. Lots of heat trapped inside as a comparison to a dark gel out the front in melting down on a scoop. BTH lamps won’t work in a 360 radial Leko fixture short of a P-28s socket extender not yet invented. Osram/Sylvania has never made such a lamp socket - I was asking them to do so and no not viable as answer. Will read and respond more if of help.

 

[ship]

On P-28s sockets there was a drive to do G-22 in the 30's thru 60's when they came out it would seem. Be glad we went P-28s in the industry as per one that has worked on the other version.

 

[ship]

ship

Thank you for contacting Mark.

I went to the college this morning to ask about their last shipment. The PO shows an August 2014 purchase. This is a new purchase and I assume this is the current product. They have three cases of Osram lamps on the shelf. I opened one of them last week. That is when I found the very rough center contact. I am sorry, but there is no way this will make a good contact with a socket.

Looking through their collection of bad lamps, I found Osram, Ushio and Eiko. The Eiko 'appears' to have a smooth contact, but I can not confirm this due to burning where the contact arced in the socket. This could be an example of a good lamp into a bad socket. The Ushio was so badly burned, I could not tell what it originally looked like. I did find something disturbing on two Osram lamps. The other terminal showed distinct signs of arcing where it connected to the shell. This appears to be a welded connection and I would not expect a problem here.

We are in a real quandary right now. There are 24 of these instruments in the house and we need them. We know we need to replace sockets, but I feel that if we put these lamps in them, with the rough contact surfaces, we will just start the cycle again and damage the new sockets. My original plan to add a brass washer to the lamps to improve the contact area is NOT long term viable even IF it works. Les has pointed this out and I agree. Polishing the contact is another possibility, but difficult to do well and provide a sufficient contact area. Then there is plan 'C', using lead free solder that melts at just over 200 C, coat the contact as evenly as I can, stick it in a socket and see what type of contact area I get. Then hope the solder does not melt and solder the lamp to the socket.

Ship, I have read several comments about sockets only lasting two to three years. The college has some instruments over thirty years old and they work just fine. The 1KW scoops are real work horses and they have been running for years. If sockets are failing after two or three years, someone needs to look into it.

I will take some pictures Wednesday and then figure out how to post them.

Ken

First, don't attempt any modifications to base or lamp in making them work. It's expensive in now needing new replacements for your show but all brands of lamp are fully warranty for any concerns you have about them if manufacture defect if it came that way or wasn't by way of bad base install. Send them back by way of your lamp supplier and it will take months at times to explain or refund but it is the proper way to do it if you believe a manufacturer problem. As with above you don't believe the lamps you saw were the problem - the bases. Replacement of lamp is normal with base, I also mentioned a silicone fiber grinding wheel for re-surface with contact cleaner/lubricant coating for a used lamp. Cheaper on buying tools than more lamps if easy to fix with care.


Sockets also fixable normally but would take time in that if fixing socket also doing re-wiring.

The solder can also melt and short between hot and Neutral as a serious problem.

Sockets can last as long as they do and are not a factor in comparison because you will find different sockts and often lamps between them.

What brand and type of sockets are failing after two to three years?

 

[Ken Johnson]

Everybody,

Thank you for your help and suggestions. Trying to fix or modify this is a waste of time and money. Replacing all the P28S sockets with new ones will put us right back where we started and how long will it take for the rough contacts on the bases of the BTRs to start arcing again. Unless the lamp manufacturers do something about improving the electrical cotact on the base of the BTR, continued use of this lamp is out of the question. We have a problem now and the sockets need to be replaced.

I am considering asking the college to convert all their Altman Fresnels to a G22 base. I will contact Altman about any suggestions they may have to ease the conversion. Comments and suggestions from the forum would be greatly appreciated. I understand that at least one of you has done this and I would like your input.

Ship, you seem to NOT like the G22 in a previous post. May I ask why.

Thank you,
Ken

 

[DELO72]

Hi Ken,

The minor irregular surface of the pin contact you showed in the photos is nothing to be concerned about. The bigger issue and cause of your concern is that most of the sockets have a conical contact plate, and the pin is round, which gives a mediocre surface contact as you correctly point out. I'm actually having my R&D team take a look at improvement options to the lamp contact (since we have no control over the lamp holder as we don't make one) to see if we can't roll out an improvement down the road later this year. If we do, I'll make sure the Control Booth public knows of it.

G22 solutions may not work as A) how do you ensure the LCL (light center length or Filament box) lines up correctly in the center of the reflector if the lamp you use with a G22 base doesn't have the same dimensions? One option to consider- I believe BMI was showing (at USITT last year ?) an upgrade kit to Altman Fresnels to use an HPL lamp. So they may have an off-the-shelf solution if I am remembering correctly. I don't recall if the solution was theirs, or Altman's.... Or I could be having one of those "Senior moments" that seem to come on the more I age.

Lamp sockets are like car tires. They don't last forever, nor were they ever intended to. If you've gone three years without arcing/replacements, that's a good run in some cases.

 

[Ken Johnson]

Mark,

Thank you for your response.

I have checked with BMI and they DO make an HPL retrofit kit for the 1KAF series. It appears to be for the 575W lamp. This could work very well for the college as they also use a lot of Source Fours.

To all who have been following this thread, thank you. I am putting everything on hold to let them think about what direction they want to go. I will report back when they make a decision or if they have additional questions.

Ken

 

[ship]

Mark,

Thank you for your response.

I have checked with BMI and they DO make an HPL retrofit kit for the 1KAF series. It appears to be for the 575W lamp. This could work very well for the college as they also use a lot of Source Fours.

To all who have been following this thread, thank you. I am putting everything on hold to let them think about what direction they want to go. I will report back when they make a decision or if they have additional questions.

Ken

In your post you started a re-design of lamp base in progress. Similar to someone else's post started the inventment of the BTH lamp here. As per original concept of Controlbooth... your ideas and thoughts need others from the industry to hear, listen to and or explain them and we do.

Mark's getting old isn't an issue than I also getting old in believeing that Altman already sells such a version, and if they do, there is an upgrade parts available kit. We are getting to replace our elders past onto us and somehow we find ourselves responsible for now,G and passing on the knowledge others - you will pass on.

That said, such G-9. lamp sockets as stated do have a specific amount of use that varies and won't be any more dependable in the long run than that P-28s base. Years of notes on how to re-surface P-28s sockets posted about, but the newer concave ones - less experience to replace in "saving" them other than sinking the Dremmel tool with silicone abrasive wheel down into the bad center contact and perhaps going more abrasive than that in gaining a surface contact to refine. Than spraying with contact cleaner with lube to clean it up, drip dry and coat the fresh contact. Could probably save the lamp socket but would need work in refining grit if arched. A P-28s socket you can fix and replace just as cost effectively as a G-9.5 you just replace in comparible prices for both sockets. P-28s is a much more long term sustainable lamp socket and will be less money spent on in the long term for re-surface or replacement. This assuming bits and time to do so, otherwise it's a wash for which to choose.

Investing in an upgrade kit will not balance out for stustainibiity of socket or lamp type.