IBM clock set time

Discussion in 'Electric Horology' started by Mopar, Jan 4, 2019.

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  1. Mopar

    Mopar New Member

    Jan 4, 2019
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    I have an IBM Type:S3 56-12 24 hour Clock
    Works on 110v ac (Regular ac plug - no third wire)
    Appears to use 3510 Hz on ac line to set time
    Would like to build circuit to inject audio on ac to set time.

    Clock.jpg
     
  2. kinsler33

    kinsler33 Registered User

    Aug 17, 2014
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    Check with the guys over at Electric Horology, which is oddly classified amongst our various message boards. They're really into these things and ought to be able to tell you how to hack the setting procedure. I also always wonder about that weird gas-filled electron tube.

    I don't know how accurate that 3150 Hz has to be, but it wouldn't be all that difficult to use a 555 timer to make the appropriate oscillator. I also don't know what on earth the required voltage of that signal might be.

    Mark Kinsler
     
  3. flynwill

    flynwill Registered User
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    Feb 1, 2007
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    https://frank.pocnet.net/sheets/201/5/5823.pdf

    It is similar in operation an SCR. A voltage on the trigger connection starts a mercury arc that then allows the tube to conduct until the current goes to zero and the arc quenches.
    The trigger needs ~ 70-100 V to trip. The transformer and capacitor circuits are designed to be resonate at the selected frequency and the transformer probably steps up the voltage considerably, but I would guess that it still needs a signal of several volts. Perhaps one of the folks that have actually worked on these machines can give you an idea.

    Building a suitable sync signal generator might be an interesting project.
     
  4. fdew

    fdew Registered User

    Jul 12, 2007
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    Anything is possible but I would isolate the clutch coil from the other components and entergise it with a external supply at the correct time (57 min 54 sec) for 8 sec from memory
     
  5. Mopar

    Mopar New Member

    Jan 4, 2019
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    Thanks, that is a quick and easy work-around.
     

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