repairing a Gralab 300?

Discussion in 'Darkroom Equipment' started by winger, Nov 8, 2007.

  1. winger

    winger Subscriber

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    I just got a GraLab 300 from fleabay ($26 inc shipping). It was said to be in great working condition. BUT, it jumps over 60 seconds to 55 sec and skips through 30 sec to 25 sec (takes more than 5 sec). Is this easily repaired or should I try to return it?
     
  2. Mike Wilde

    Mike Wilde Member

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    only if you are mechanically minded

    I have never had a need to pull a 300 apart, but have fixed other mechanical/electrical timers.

    Most of the time the motor drives the gears that cause the dials on the front to move, and also turns a hidden in the back gear with notch, or gear with trip cog on it to contact an electrical limit switch. When the limit switch (sometimes more than one) is contacted that shuts the motor off, closes the time out switch, etc. In your case it sounds like there is a literal screw loose somewhere. Look what the cog/notch etc is lined up with as it apporaches zero/60 You may find that the shut off switch has fallen off of its mounting bracket in shipping it to you. .
     
  3. bdial

    bdial Subscriber

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    There are set screws that hold the hands on, are these tight? Presumably, the hands are not bent?
    I've not been inside one recently enough to know if there are any easy repair prospects internally.
     
  4. Alex Hawley

    Alex Hawley Member

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    I agree with bdial, it sounds like the hands are loose. They are shifting while they pass through the 12 and 6 (aka, 60/30) regions. May be as simple as tightening the set screws that secure the hands to the spindles.
     
  5. rgeorge911

    rgeorge911 Subscriber

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    Ten years after...

    I just had a problem with the seconds hand and dial having a lot of play in it, making accurate timing impossible. The big plastic GraLab knob in the center is held in place with a set screw, which you need a small "star driver" to tighten. The single screw holds both the plastic knob in place, and tightens the second hand against the timer shaft. Very easy to tighten once you have the tool. My timer is now as good as new.

    Reed
     
  6. Nodda Duma

    Nodda Duma Subscriber

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    I've taken apart a Gralab 300 to repair a non-functional buzzer. There is not much to them. I agree that you should check the set screws for the hands, which doesn't require you to dismantle the box.