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dimmer questions

Discussion in 'Lighting and Electrics' started by moderately_clueless, Feb 8, 2006.

  1. moderately_clueless

    moderately_clueless Member

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    I'm high school with relatively outdated equipment. We currently have a 48/96 dimmer rack. It's a CD80 strand century. It's from the early eighties. Our dilemma seems to be that many of our dimmer ghost, pop up or do other random things. We've had a repair guy come in twice recently and he looked at all of our dimmers and said they were fine. However, the very next night, they were ghosting again. I've dusted in and around the dimmers, switched out the location in the rack, just about everything. The man from Operashop saw nothing wrong with them, yet they still ghost. Any solutions I haven't thought of yet?
    Also, another random curiosity that's been bothering me for a while. Is it acceptable to mix gel colors to get the right look? I assume it's alright, but there's probably some random reason not to.
    Thanks.
     
  2. disc2slick

    disc2slick Active Member

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    Hey,

    I'm far from an expert in dimmer troubleshooting. If they are ghosting, I don't think it is an air-flow problem, which is one of the main causes of dimmer trouble. I'd say check all your dimmer profiles to make certain they aren't set to something wierd, depending on the set-up you can do this either on the dimmer rack itself, or through the board.

    in terms of your question about mixing gels. I'm not sure what exactly you mean, but i've always believed and been taught that if it achieves the look you want go for it by all means. Especially when it comes to color choice there are very few hard and fast rules. Just do what looks right, y'know.

    -dan
     
  3. ship

    ship Senior Team Emeritus Premium Member

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    Find a new dimmer repair guy.
     
  4. koncept

    koncept Active Member

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    i have used a cd 80 dimmer system, if the one i am thinking of is anything like yours it does not have the many controls on the dimmer rack, at least ours doesnt. i would definately find a new repair guy and chekc the board (cues, macros, subs)

    good luck with this problem though
     
  5. BillESC

    BillESC Well-Known Member Premium Member

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    I suspect there is a trim adjustment on each of the dimmer modules that you can use to zero them out. What protocol does your system use, is it analog, DMX or AMX? It is possible the system was set up with the dimmers set to a filament glow.
     
  6. moderately_clueless

    moderately_clueless Member

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    Erm, dumb question , but what's the dfference between AMX and DMX?
     
  7. koncept

    koncept Active Member

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    it is the type of signaling the dimmers operate on

    amx - analog variant (4 pin cable)
    dmx - digital (5 pin cable)

    im sure someone with more knowledge of the difference will be along.
     
  8. Footer

    Footer Senior Team Senior Team Premium Member

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    amx (in its native form) can carry 192 slots of info... dmx can carry 512.... properly terminated amx will work just as well as dmx.... what kind of board are you using?
     
  9. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    Before we go too far down the path of speculation, let's go back to the begining... What if your Dimmer Repair guy is right? Are you sure the problem isn't in the board?

    As for mixing Gel, the only negative is that you are double filtering the light so you loose intensity. If 50% transmit's through the first gel and then 50% transmits through the second gel, only 25% is going to make it all the way through. So the negative is it might end up a lot darker than a single gel of similar color. If that's not a problem for you, go for it.

    I also want to add that you can sometimes do cool things with cutting two gel's in half, and taping them together side by side. For example a leaf green and a yellow, taped side by side shining through a leaf gobo looks nice. Just cut lay them side by side and tape right down the seam on both sides of your new gel. It's a poor man's colorizer. Be sure you buy the tape that is clear and feels sort of like gel plastic... I think it's typically called "transparent tape" You don't want the kind that is sort of cloudy white but looks clear when you put it on paper.
     
    Last edited: Feb 19, 2006
  10. RiffRaff54

    RiffRaff54 Member

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    i had the same problem at my theatre, but it was just our house lights that would ghost. some one said the ramp might need adjusting. i dont trust myself playing with the electronics of a dimmer rack, so i didn't mess with it. but it quit after a couple of weeks and hasn't done it in about a year.
     
  11. moderately_clueless

    moderately_clueless Member

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    We have an ETC 48/96 express. We also have an ancient mantrix. But I'm pretty sure the problem isn't in the boards. The only time the boarsds cause trouble is when they are both on, but the trouble is that when the dimmers are causing problems, the board is rarely on.
     
  12. jacobbiljo

    jacobbiljo Member

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    not as much of a reply but rather a related question. Our school had 2 six channel 0-7/1-15 volt dimmer packs which where giving us troubles. Im kinda new to the theatre terms so i'll just say they were giving us a candle effect(is this ghosting?). We now have a new dmx system and the problem is gone. I took the old dimmer packs home and am now working on them. I have built myself a six channel lighting board with audio chasers and 3 selectable scenes. I was wondering if anyone had any advice on how to get rid of the candle effect. If people are comfortable with electronics, they can open up the dimmers and exchange the triacs out with new ones. It is a fairly simple job involving removing two screws and 3 spade plugs, as long as you have ensured that the capacitors have discharged. I was wondering if there is an easier way than spending $40 per triac to get rid of the flicker.
     
  13. gabe

    gabe Member

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    The same thing happens with our 60 year old dimmers, we've given up and called it the theatre ghost.
     
  14. avkid

    avkid Not a New User Fight Leukemia

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    Are the boards isolated from other?
     

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