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  1. #1
    Randy Moe's Avatar
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    Omega Super Chromega F dichroic II rewire for 120 v bulbs

    I am about to rewire an Omega Super Chromega F dichroic II for this, Sylvania / Osram ELH (300W/120V) Lamp, which seemed cheapest from B&H. Of course 4 lamps as original.

    I will add a new full circuit overheat cutoff switch at the factory setting of 130 degree F.

    Most likely it will be easiest to not wire for the lamp failure lights on the now redundant power supply. I'm splitting the power inside the head.

    I am also thinking of hacking a DIY timer as lately I am having trouble with used timers. Since this is 1200 watts I will need a relay anyway.

    Any advice is welcome.

    Anyone else done this?

  2. #2
    JackRosa's Avatar
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    Lamp Failure

    Randy: it sounds like you know your stuff. The relay will be a piece of cake for you. Only comment I have is: (for me anyway) it is difficult to tell when one of the bulbs is off unless the failure lamp lights turn on. If you are going to disconnect this circuitry, this is something to keep in mind.

    Have you had the enlarger (head) for long? I have had my Omega F for many, many years and it has never given me trouble. Routine maintenance stuff: changing the styrofoam liners, cleaning, lubing certain parts. Had the dichroic filters changed (about 7 years ago). I understand they are indestructible.

    Good luck with the project.
    Jack Rosa

  3. #3

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    Hi Randy,

    This seems like an expensive idea unless you already have a nice 120V power supply. If you do have a source of nice steady power, why not simply rewire the entire head for 120V? You'll have a nice clean install and one less transformer to start buzzing as time goes on.

    Timer? Every time I look at building a timer, the difference in the cost of buying a brand new one always seems less than my time. I have always thought that a PLC would be the easiest way to combine all the jobs required to control an enlarger and they are really cheap at automation direct. But whenever that idea pops up, I remember that my enlarger works just fine the way it is. <G>

    In any case, I actually hope that you build a really cool control system and then post it on the forum.

    Neal Wydra

  4. #4
    ic-racer's Avatar
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    I was going to do a 120v conversion on a Chromega D but the cost of the appropriate connectors and sockets to made it more economical to find a power supply to repair. Turns out we got a free Power Tower that was easily fixed with a new SCR. That probably won't happen for an "F" power supply

    You can run a fiber optic cable from each lamp to create a series of indicators on the front panel.

    http://www.apug.org/forums/forum43/6...a-ii-120v.html
    Last edited by ic-racer; 01-26-2014 at 10:41 AM. Click to view previous post history.

  5. #5
    wildbill's Avatar
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    Fwiw, on my fotar/chromega I had to add 4 layers of lee 216 diffusion over the bulbs to get long enough exposure times even at f16 on a 240mm printing 11x14's (b+w). 1200w worth is a lot of light.
    Are the original lamps too hard to find?
    www.vinnywalsh.com

    I know what I want but I just don't know how to go about gettin' it.-Hendrix

  6. #6
    Randy Moe's Avatar
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    I am rewiring the head for 120V, I thought that was clear.

    I am doing this to eliminate the 24 volt power supplies which must be very unreliable as it came with 4 of them. I just don't see the point of running 24 volt. Cost of conversion is minimal.

    Primarily my initial problem is/was bad cabling and missing interlock connectors. The seller said it worked as is, but it sure doesn't.

    The mixing box is fine, and I am doing only B&W and will use it for 8x10 to 16x20 or larger.

    The timer is still a WIP. But I do know it won't be a f-stop timer...

    Vinny, I know 1200 watts is a lot of light, my DIY 1000 watt LED head needs to run at 20%. I may use this on a horizontal wall mural projection chassis.

  7. #7
    Randy Moe's Avatar
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    ic-racer, fiber optic it will be, great idea.

  8. #8
    Randy Moe's Avatar
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    Neal, perhaps this timer, it is rated right at my load OTB, kinda tiny, I could put it in the head! But that's a bad idea with tall enlargers...

    http://www.automationdirect.com/stat...rtimertach.pdf

  9. #9
    Randy Moe's Avatar
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    Jack Rosa, if I could find new filters I would change them, just because. I need to do more research and perhaps find newer and different sources for these filters. One filter has been replaced and I found the one that fell out, inside the head in perfect condition. I may just clean everything. like I wrote, I will not be doing color and everything becomes relative.

  10. #10
    JackRosa's Avatar
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    Help with Dichoric Filters

    Randy: I think it was around 2007 when I had my Omega F head completely refurbished by Focal Point (in FL). Michael Sparks was very helpful and knowledgeable. I would think he would be able to help re: dichroic filters.

    His e-mail was mike@fpoint.com and the url was www.fpointinc.com. Hope this helps. Feel free to let him know I referred you.
    Jack Rosa

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