Vintage Lighting Help with an old model Davis Dimmer

jreeves1701

New Member
Help.

I am looking for any technical information, schematic or otherwise on this particular model Davis Dimmer. I am the director of a new theatre program in West Point, Mississippi. My mentor and technical theatre guru has helped me with the basic history of Ariel Davis, even shared the story about meeting the inventor and sharing a beer. Here is a photo of the beast.

20180926_135008.jpg


At some point, the school got the notion to upgrade and had Lehigh come in and they jerry-rigged the entire system through a secondary circuit breaker box on the wall to the left, and then installed a 9-circuit dimmer panel (the black box on the right). So all of the circuit breakers on the Davis Dimmer are still live and active. But are also redundantly patched into the new circuit breaker. Now I am in a position to reverse engineer this mess and rewire it properly so that the school auditorium can be properly wired for theatrical lighting. We are actually looking to remove the entire Davis Dimmer completely. It is a hot mess, let me show you the instruments.

The "vintage" Major B-156 border lights. Not patched into the Davis Dimmer anymore, nor the Lehigh system, or at least not that I can tell.

20180926_134659.jpg


Yes, someone decided to remove all the roundels from it. All but a few of the lights were kept. Instead of the PS bulbs, maintenance got extenders and installed low-wattage standard bulbs. I am in the process of relighting these instruments with LEDs and replacing the missing roundels. We have two of these B-156s, one on the first electric and one on the second. I think there was one on the third electric but it was removed. As I mentioned they are not hooked up to the Davis Dimmer or the Lehigh Dimmer Panel that I can tell. They are controlled from the booth by two residential dimmer sliders. Once, I figure out how to properly upgrade our dimmer system, I am looking to replace these with something more versatile. As well as take them off the residential controls.

And now for our alcove lights.

20180926_134515.jpg


These are the most modern instruments. They were installed when Lehigh came in. However, they are poorly patched into the Lehigh dimmer panel. As I mentioned there are 9 circuits. Space for 12, but only 9 installed. There are two assigned instruments per circuit/channel. There are a total of 8 circuits on each side of the alcove electric. However, the four unused sockets don't seem to be hot. I have attempted to add instruments but didn't get them to work.
 

Mac Hosehead

Well-Known Member
I have seen Ariel Davis dimmer panels before but I'm not sure I've seen one in actual use. They are a linear-swipe autoformer. So they will have the same problems as other autoformers, i.e. worn brushes, arcing contacts. I don't know if any replacement parts are available. It probably should have been removed at the first upgrade but that is a big project in itself.
 
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jreeves1701

New Member
I have seen Arial Davis dimmer panels before but I'm not sure I've seen one in actual use. They are a linear-swipe autoformer. So they will have the same problems as other autoformers, i.e. worn brushes, arcing contacts. I don't know if any replacement parts are available. It probably should have been removed at the first upgrade but that is a big project in itself.
My plan is to remove it. But since it has been patched through, I was trying to get an idea of the inner workings so that I can better estimate the cost. I'm fairly sure that the whole thing is redundant and ready for replacement.
 

derekleffew

Resident Curmudgeon
Senior Team
Premium Member
... My mentor and technical theatre guru has helped me with the basic history of Ariel Davis, even shared the story about meeting the inventor and sharing a beer.
Your mentor told you he shared a beer with Ariel R. Davis? I'm sorry, I'd have to be extremely skeptical of anything that person says.

The wiring in the walls from the dimmer location to the outlets in the lighting positions is the only thing you have worth saving. Chuck the rest and replace with modern dimmer and/or circuit breaker/relay panels.
 

jreeves1701

New Member
Your mentor told you he shared a beer with Ariel R. Davis? I'm sorry, I'd have to be extremely skeptical of anything that person says.

The wiring in the walls from the dimmer location to the outlets in the lighting positions is the only thing you have worth saving. Chuck the rest and replace with modern dimmer and/or circuit breaker/relay panels.
Gutting the Davis Dimmer and chunking it is the ultimate goal. It takes up vital wing space and is nothing more than a redundant circuit breaker. There is no use for it and it amazes me that Lehigh did not remove it when they installed their equipment. But as a public school, I'm sure the contracted job was lowballed and removing the old equipment was priced out of the project.
 

Gage

Member
Unfortunately, I don't have anything very meaningful to help with your problem, but I do enjoy seeing this sort of stuff. It's always interesting seeing these older systems, especially ones that are still around in one form or another. If I wasn't on the other side of the US, I would be glad to give the Davis stuff a new home. I would guess it's being treated as a "standard" electrical panel at this point, although with some of what you are describing I'm definitely skeptical. Like @derekleffew said, the wiring from dimmer to fixture is most likely all that's worth keeping.
 

microstar

Well-Known Member
Here is some info on the inner workings of the Davis autotransformer dimmer. These things were nearly bulletproof and probably worth a fair amount of money for the copper in them today!
The Showboat Theater at the Univ. of Washington had one just like this when I was in graduate school in 1972... possibly had more than 12 dimmers.
I agree with Derek that it was highly unlikely your mentor shared a beer with Ariel Davis...you will have to do a little research to find out why.
CLEAR photos and complete information would go a long way to helping folks offer more than guesses at improving your lighting system. How about good photos of the Lehigh dimming cabinet AND the controller they supplied?
When you say the alcove circuits are poorly patched into the dimmer cabinet, do you mean there are 12 spaces for dimmers in their cabinet but only 9 dimmers are installed?
I also think you are unfairly bashing Lehigh for mistakes made by whoever contracted them to do the work (probably an administrator who did not do due diligence). Lehigh has been in business for a very long time and makes
good equipment. While the two strip lights SHOULD have been connected to the new dimmer cabinet, if Lehigh's contract did not include that, then you cannot blame them for not doing so. Lehigh could have made the suggestion
to do so but it possibly was rejected by the school. Stage lighting installers generally do not have licensed electricians working for them and this is an additional expense the school would have to bear if their maintenance people
did not do the work. Sorry to be a little bit negative but I think you are making a lot of assumptions. Looking forward to seeing some more photos of your system though.
 

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jreeves1701

New Member
Not trying to knock anyone. I have got plenty of technical documentation from Lehigh. I like their equipment. Yes, the dimmer panel has 12 circuit slots but only 9 are installed
20180926_135013.jpg
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My mentor (college professor) was young when he met Davis in Salt Lake City. I have every reason to believe that they met. It was in the 60s. I'm sure my mentor had a drink in his hand when he met Davis. But that is all irrelevant at this time. I am trying to improve the electrics in my space.

The controller for the Lehigh system is a DSQ12 controller. I am still trying to figure out exactly how the lights are patched. I have figured all of it out except for the 4 unused electrics in the alcove. I assumed it was the two circuits on the panel that do not control any of the instruments. I am still convinced that they are but have yet been able to confirm it, as every instrument that I have plugged into the empty twist lock receptacles has failed to illuminate.

I am still working on refurbishing the Major Borderlights and ultimately replacing them with distribution bars but before I can do that I need to make sure I fully understand how the Davis Dimmer is patched into the Lehigh dimmer board and vice versa.

Most of this work is so that I can get a rough estimate of how much funding to request for a grant application to contract a contract electrician to help replace the Davis Dimmer, upgrade the Lehigh Dimmer Panel, and rewire the 1st, 2nd, and 3rd electrics.
 

jreeves1701

New Member
Here is some info on the inner workings of the Davis autotransformer dimmer. These things were nearly bulletproof and probably worth a fair amount of money for the copper in them today!
The Showboat Theater at the Univ. of Washington had one just like this when I was in graduate school in 1972... possibly had more than 12 dimmers.
I agree with Derek that it was highly unlikely your mentor shared a beer with Ariel Davis...you will have to do a little research to find out why.
CLEAR photos and complete information would go a long way to helping folks offer more than guesses at improving your lighting system. How about good photos of the Lehigh dimming cabinet AND the controller they supplied?
When you say the alcove circuits are poorly patched into the dimmer cabinet, do you mean there are 12 spaces for dimmers in their cabinet but only 9 dimmers are installed?
I also think you are unfairly bashing Lehigh for mistakes made by whoever contracted them to do the work (probably an administrator who did not do due diligence). Lehigh has been in business for a very long time and makes
good equipment. While the two strip lights SHOULD have been connected to the new dimmer cabinet, if Lehigh's contract did not include that, then you cannot blame them for not doing so. Lehigh could have made the suggestion
to do so but it possibly was rejected by the school. Stage lighting installers generally do not have licensed electricians working for them and this is an additional expense the school would have to bear if their maintenance people
did not do the work. Sorry to be a little bit negative but I think you are making a lot of assumptions. Looking forward to seeing some more photos of your system though.
Thank you for this. The technical plate on the Davis Dimmer has aged to the point it can't be read. The serial plate is still intact.
20180926_135216.jpg
 

TimMc

Well-Known Member
Premium Member
The "what's between the lines" regarding having a beer with Mr Davis - he's from "behind the Zion Curtain" and likely of a faith tradition that does not use alcohol. That your mentor might have had one is equally likely. What is not, is that Mr Davis was having one, too.
 

microstar

Well-Known Member
Regarding your border lights, several things to think about if you are going to continue to use them.
In the absence of specs for the Major brand, I found similar units in a 1965 Kliegl catalog and the roundel type typically don't use anything less than a 100 watt lamp. Wondering if you measured the diameter roundel required and compared it to the Kliegl info if it would lead to the lamp shape/wattage originally used? You would need this to find replacement roundels anyway. It takes a pretty good punch to get any usable light out of colored glass in primary colors, so it is important to try to find out what wattage lamps the fixture is rated for. Assume you looked for lamp info on the fixtures (sometimes listed inside the lamp compartments). Are you certain the original lamps were PS or could they have been R40? In any case, border lights consume huge amounts of wattage even when broken up into 3 or 4 circuits (RGB or RGBW or RBW). For a basic stage, border lights can be a good solution and were certainly the go-to solution for many decades especially in school auditoriums.
Obviously you will have to be careful choosing lamps so as not to overload the residential dimmers they are connected to as some are only 600 watt capacity. If there is only one dimmer for each border light, you obviously will not be able to control each color individually.

While LED replacement lamps sound like a good idea, again several issues to be aware of.....
they must be "dimmable" LED's and emit light from the end of the lamp as well as the sides as some do not.
they must be rated to operate in an enclosed compartment if used with roundels.
they must be tested to work without flickering on the dimmer used with them. Not all dimmable LED's work with all types of dimmers.
if used with roundels, be of sufficient wattage to produce usable light on the stage.

Lastly, how about a photo of the new breaker box showing the breakers? Curious as to whether it is just a main breaker or branch breakers.
 

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jreeves1701

New Member
Regarding your border lights, several things to think about if you are going to continue to use them.
In the absence of specs for the Major brand, I found similar units in a 1965 Kliegl catalog and the roundel type typically don't use anything less than a 100 watt lamp. Wondering if you measured the diameter roundel required and compared it to the Kliegl info if it would lead to the lamp shape/wattage originally used? You would need this to find replacement roundels anyway. It takes a pretty good punch to get any usable light out of colored glass in primary colors, so it is important to try to find out what wattage lamps the fixture is rated for. Assume you looked for lamp info on the fixtures (sometimes listed inside the lamp compartments). Are you certain the original lamps were PS or could they have been R40? In any case, border lights consume huge amounts of wattage even when broken up into 3 or 4 circuits (RGB or RGBW or RBW). For a basic stage, border lights can be a good solution and were certainly the go-to solution for many decades especially in school auditoriums.
Obviously you will have to be careful choosing lamps so as not to overload the residential dimmers they are connected to as some are only 600 watt capacity. If there is only one dimmer for each border light, you obviously will not be able to control each color individually.

While LED replacement lamps sound like a good idea, again several issues to be aware of.....
they must be "dimmable" LED's and emit light from the end of the lamp as well as the sides as some do not.
they must be rated to operate in an enclosed compartment if used with roundels.
they must be tested to work without flickering on the dimmer used with them. Not all dimmable LED's work with all types of dimmers.
if used with roundels, be of sufficient wattage to produce usable light on the stage.

Lastly, how about a photo of the new breaker box showing the breakers? Curious as to whether it is just a main breaker or branch breakers.
Thank you. Yes, I am taking all the things you mentioned into consideration. And selecting the right bulb is primary on the list. Second is the size and color of the roundels if I can even use them. They are currently controlled by a residential slider switch but I think that they might actually be dimmed using the Lehigh dimmers. Or possibly the only thing still being controlled by the Davis Dimmer. I really wish I was employed here when the Lehigh install took place. I am working on many unknowns. That is why I am doing so much research before cutting the main and inspecting the system or better yet, calling someone in.

I have documented specs on Major Border Lights

 

cbrandt

Well-Known Member
I've helped a couple schools with led "upgrades" on border strips like these. They don't use them for production though, just for class on stage, rehearsals, recitals, that kind of thing where the lights will not be dimming much or at all. They work great for that, if you can accept the compromises.
 

jreeves1701

New Member
I have used them for production but only for general lighting the upstage or downstage areas. The lights on the house electric until recently were not focused and the ellipses had all their shutters closed. The school did not have a tall ladder so, I finally secured the funds to purchase one. Still about a foot too short but I can at least reach the instruments to gel and focus them. The patch work is still in need of work. I don't have one on one control of the lights. They are each paired with another.

And last year the district decided to add additional projectors for side projects. Look forward to using the projectors in productions but they installed them directly in front of the stage lights. Another example of not consulting the technical theatre person.
 

microstar

Well-Known Member
Great find on the Major catalogs and data on the exact model strip lights. Until you can determine if the Davis dimmer is still hooked up to some of your circuits, it will be slow going.
An electrician can do this easily.
 

Ted jones

Well-Known Member
I used to repair Ariel Davis equipment in the '70's. And their progeny, Electro Controls.

We replaced a system with Davis Slide-Patch a few months ago at Percy Julian HS here in Chicago. Unfortunately, I wasn't able to salvage one of them. They were a pain to work with but they looked cool. You needed cans of Carbon Tet to keep them working. Especially when people hot patched them. My then employer told me to spray and run. Wait for a few minutes and do it again.

Ahhh. The good ol' days???

T
 

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