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  1. #1
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    Default IBM Model37 master clock

    Does anyone still have the information on the model 37 master clock. I am restoring one and would like to have a copy of it. Thank, Scot

  2. #2
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    Default Re: IBM Model37 master clock (By: Scot Traffis)

    Try the IBM archives, clock corner.
    harold bain, Member ch 33
    "If it won't "tick",
    let me "tock" to it"

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    Default Re: IBM Model37 master clock (By: harold bain)

    just purchased a Simplex type 37 master clock does anyone have a wiring diagram for it? Also am looking for a rating nut for the invar pendulum. Thanks, Scot

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    Default Re: IBM Model37 master clock (By: Scot Traffis)

    Nothing in the archives on the type 37. Could really use a wiring diagram as I have 2 wires that are loose in the case that come from a terminal block behind the movement. Will try to post some pictures of my clock and the extra movement that I have

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    Default Re: IBM Model37 master clock (By: Scot Traffis)

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    Here are the pictures of my clock with the extra movement. The movement in the clock is unmarked and the extra is marked International.
    Last edited by Bill Stuntz; 02-28-2017 at 09:30 PM. Reason: Replace BIG photos w/ expandable thumbnails

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    Default Re: IBM Model37 master clock (By: Scot Traffis)

    Does anyone know what type of antenna this movement would take?

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    Default Re: IBM Model37 master clock (By: Scot Traffis)

    Wow, what an interesting clock.
    Depending on what year it was made, the antenna could just be a long
    wire or it could be a coil assembly. A long wire would usually want a transformer
    to match the cable.
    If it were a low frequencey time reference, it would use a ferrite rod with a coil.
    My thinking is that it is likely connected to a long wire and receives 5/10/15 MHz
    WWV signals. Most likely fixed to one of those frequencies. Some pictures of the
    receiver, top and bottom would help determine the frequency.
    If a fixed frequency, it would most likely use a crystal for the VFO part of the receiver.
    Many of these old receivers need paper capacitors replaced. Some of the IF transformers
    have silver plated mica capacitors that need to be replaced as well. These have unprotected
    silver that oxidizes and actually shorts them out.
    Tinker Dwight

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    Default Re: IBM Model37 master clock (By: Tinker Dwight)

    The micro switch next to the hour hand does not look like it belongs to the clock.

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    Default Re: IBM Model37 master clock (By: Steve Murphy)

    Both movements have the switch but the one in the clock has nothing attacked and
    the actuating lever is missing. I think it was just an unused option that was added
    to the design later.
    I think if you want a schematic, you'll need to sit down with a sounding ohm meter
    and start tracing things out.
    The receiver may not need complete tracing to fix. Many of us older radio
    people could most likely figure it out without a schematic. There are not
    a lot that has changed in these from around the 1950's.
    Tinker Dwight

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    Default Re: IBM Model37 master clock (By: Tinker Dwight)

    my clock does not have that switch, maybe a modification, my clock is branded "Simplex", but seems identical to the IBM. Simplex bought IBM'S time clock business in 1958. I have been told that WWB changed their signal coding and these clocks will no longer correct.

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    Default Re: IBM Model37 master clock (By: Steve Murphy)

    Thanks to all who replied. After doing some checking I think the signal these clocks need is no longer available. They are an interesting clock. Both my clock and the extra movement have the microswitches but they are not hooked up to anything. My clock is branded Simplex with an unmarked movement and my extra movement is marked International. This is the newest master clock of my collection. I have a Standard Electric, a Stromberg, a Monarch, a McClintock, and four different Internationals. I just enjoy the mechanics and electrics of the old clocks.

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    Default Re: IBM Model37 master clock (By: Scot Traffis)

    Quote Originally Posted by Scot Traffis View Post
    Thanks to all who replied. After doing some checking I think the signal these clocks need is no longer available. They are an interesting clock. Both my clock and the extra movement have the microswitches but they are not hooked up to anything. My clock is branded Simplex with an unmarked movement and my extra movement is marked International. This is the newest master clock of my collection. I have a Standard Electric, a Stromberg, a Monarch, a McClintock, and four different Internationals. I just enjoy the mechanics and electrics of the old clocks.
    The receiver has a speaker, one can still use that to sync the clock manually.
    There is a WWV and a WWVB but I've not heard of WWB?
    There was a WWVL as well at 20KHz but that is not used any more.
    WWVB is at 60KHz. The antenna would be a loop. One could most likely
    experiment with an oscillator and a ferrite antenna rod form a transistor radio.
    It has changed the modulation method over the years.
    It might be fun to use a DSP to demodulate the signal using
    the receiver you have as a front end.
    There are a few ham operators that still have that kind of knowledge in
    your area. You might check with a local ham club.
    Tinker Dwight

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    Default Re: IBM Model37 master clock (By: Tinker Dwight)

    Thanks for the info. There is a ham radio club in the area, I will see if one of them might want to help me with the project. They actually have a swap meet not far from my house that I go to, sometimes I find some clock related items there.

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