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  1. #11

    Join Date
    Mar 2004
    Further question: Does the enlarger ever turn on without being first turned on
    by the timer?

    There are two scenarios:

    1) The timer's contacts are being 'welded' shut by the inrush current
    of the enlarger. If the timer is controlling a relay in the enlarger's
    power supply this is probably not the cause. However, if the timer
    is controlling the lamp current directly then contact welding may
    be the culprit. Does the enlarger turn off if you give the timer a
    good whack?

    2) More likely: The timer's output relay may have a snubber circuit across the contacts [or SSR output triac] to prevent arcing with
    cold-light heads and this snubber circuit passes enough current to
    activate the enlarger's power supply.

    A quick fix is to put a small resistive load at the timer output so the
    timer turns on both the load and the enlarger. Try a 7/15 watt light
    bulb for a test - plug an outlet strip into the timer and plug the light
    bulb and enlarger into the strip - and see if this fixes the problem.

    If solves the problem then putting the light bulb in a black box would
    be the easiest solution. A 1 watt 22K resistor wired accross the
    enlarger's relay coil/SSR LED would be a more permanent fix.
    Nicholas O. Lindan
    f-stop enlarging timer - http://www.nolindan.com/da/fstop/index.htm

  2. #12

    Join Date
    Oct 2003
    Many thanks for all your answers. I tried Linden and Tran's suggestion of putting a low-wattage bulb in parallel with the enlarger. The timer then worked OK. When I turned off the lamp, the timer often stayed on. When I turned on the light again while the timer was "stuck" on, the timer switched off. Interestingly, I borrowed a very old GraLab 450 timer that has push button-controls (and maybe an electromechanical relay). It worked perfectly. Geary, I agree with you on f-stop timing. But being rather new to enlarging I found it easier to use Stouffer's 1/3 and 1/6 step wedges. Usually, with two test strips then, I can get in the ballpark and then switch to full or half sheets. Thanks again. Rick

  3. #13
    galyons's Avatar
    Join Date
    May 2003
    San Francisco Bay Area
    Good! It sounds as if you can print, which is most important. When I had my Omega DV2 with coldlight head I had timer issues and it was most frustrating to sort out!

    Print away!! If you want to try out f-stop timing, IIRC, there are several spreadsheet programs available to do the conversions, Palm programs, and programmable calculators, as well. But they will all be a PITA until you get equipment designed to handle the math and timing interconnected for you. (Just my plug for the RH Designs products, as a happy consumer, only!)

    But your flag decal won't get you into Heaven any more. They're already overcrowded from your dirty little war.
    Now Jesus don't like killin' no matter what the reason's for, and your flag decal won't get you into Heaven any more. – John Prine

  4. #14

    Join Date
    Aug 2006
    Madison, WI
    Medium Format
    Sorry for your troubles Rick. I have been experiencing the same issues with a gralab 450 and an LPL 6700. It has been driving me nuts, particularly as I waste paper when the enlarger lamp spontaneously turns on. After reading this thread today I ordered an LPL timer, hopefully that will do the trick. thanks to everyone for their useful suggestions.

  5. #15

    Join Date
    May 2006
    Aurora, IL
    So what are you going to do with the Gralab 450? I can use one for my Beseler 45 MX.

  6. #16

    Join Date
    Oct 2003
    Sorry Tran but the infamous timer has already found another home.

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