Precise Watch Timer

Discussion in 'Horological Tools' started by Don Meyers, Jan 13, 2011.

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  1. Don Meyers

    Don Meyers Registered User

    Oct 30, 2010
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    I have the above timer also labeled MJ Lampert & Sons, New York, NY. It doesn't have a tape output. I only has a dial that has a spinning disc with a syncronous motor driving it. On the disc is a neon strobe that flashes a bar that goes around the dial and will also stop in one spot depending on the position of a tuneing knob.

    I am wondering if anyone is familiar with this kind of timer and would have a manual or any suggestions on the operation of it.

    Thanks, Don M.
     
  2. Tinker Dwight

    Tinker Dwight Registered User

    Oct 11, 2010
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    Calif. USA
    Hi
    I would assume that there was another neon light
    that you could shine on the balance wheel of a watch.
    If you know the RPM of the disk, you could then adjust
    the neon to flash a some number of times per revolution.
    One would choose the flash rate to match the balance
    wheel time ( either looked up in a table or calculated from the
    escapement wheel and gears to either the second hand
    or minute hand ).
    As an example say the watch had three cycles of the
    balance wheel for each second.
    If the dial rotated at one revolution every 2 seconds,
    you'd set it so that there were 6 flashes every rotation.
    Now, with the light flashing on the watch, you'd adjust
    the watch so that it would seem to stop at one point
    of the swing.
    For a finer tune, adjust the strobe to slip a little and have
    the balance wheel just taking the impulse from the lever.
    Try to hold this by adjusting the strobe.
    Make fine adjustments to the clock so that when you
    adjust the strobe, it no longer moves but stays stationary.
    Cool idea. I like it.
    Tinker Dwight
     
  3. Don Meyers

    Don Meyers Registered User

    Oct 30, 2010
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    Thanks for the reply. I forgot to mention that there is a pickup just like on a Tickoprint machine and there is also a built in speaker where you can listen to the beat of the watch.

    Don M.
     
  4. Tinker Dwight

    Tinker Dwight Registered User

    Oct 11, 2010
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    Calif. USA
    Hi
    Then it is a little different than I'd mentioned. The
    pickup would cause the neon to flash. The adjustment
    knob is most likely a sensitivity adjustment.
    Again, you'd adjust the clock to stop the apparent
    rotation of the lamp as the disk rotated.
    I doubt it would be much use on small pendulum
    clocks. Most have things like 68.xxx cycles per
    minute.
    Try it on a watch.
    Tinker Dwight
     
  5. Don Meyers

    Don Meyers Registered User

    Oct 30, 2010
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    I have experimented on various pocket watches. With the adjustment knob, there does seem to be a place where I can get the stobe to set in one place and flash. If I turn the knob further to the the right, the strobe races around the dial. It will go one way and there also seems to be a spot where it will reverse and go the other way. The problem seems to be that the stopping points are not always the same on a given watch. It seems to vary. The adjustment knob turns a 100K potentiometer. I have checked the tubes, replaced the caps and checked the resistors. It is a fairly simple circuit. I have worked on lots of 20s and 30s radios. This circuit just has a 12AX7, a 2D21 and a 6AU6 tube.

    I was just wondering if I had missed something in the setting up and using the timer. The dial has lines going across it's face with an arrow going left (slow) and right (fast) from the vertical line.

    Thanks,
    Don M.
     
  6. Tinker Dwight

    Tinker Dwight Registered User

    Oct 11, 2010
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    Calif. USA
    Hi Don
    It is possible that the pickup isn't working.
    There is another thread about finding a pickup.
    They note that the pickups used crystal mics.
    These old mics have mostly gone bad as moisture
    gets into the crystal and damages it.
    There is a pointer to a possible fix, using a piezo
    buzzer. I don't think they wired it the best way
    but it does work.
    My guess is that without a good pickup, it is
    most likely just free running when the gain
    is turned up.
    With the speaker, you should be able to clearly
    hear the ticking of the watch.
    As I recall, the 2D21 is a thyratron. That is most
    likley yo make a one shot.
    Another thing to look for is power supply ripple.
    The filter caps in these old electronics are often
    really gone.
    Tinker Dwight
     
  7. Don Meyers

    Don Meyers Registered User

    Oct 30, 2010
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    Thanks Tinker for the suggestions and information. I have replaced the filter caps as well as the other tubular caps. There are 3 or 4 ceramic caps I haven't replaced. These usually don't go bad. I'll have to check them. I have checked the resistors and there might be a couple that are a little too far off. I'll double check.

    I do have a good solid tick in the speaker when a watch is in the holder. The pickup was unglued from one of the posts in the pickup. I reglued it and that seemed to make the pickup work. At least it is easily heard in the speaker. The 2D21 tube checks out okay on my TV-7 tube tester as do the others.

    I guess I am just wondering how I should be using the machine to check a watch. Do you just turn up the gain until the light stops in a spot right or left of center to indicate fast or slow and then adjust the watch until the light blinks at center?

    Don
     
  8. Tinker Dwight

    Tinker Dwight Registered User

    Oct 11, 2010
    13,666
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    Calif. USA
    Hi Don
    I would assume that one would turn it up until the
    light just synced with the speaker. If the watch were
    running at a fractional part of a second, it should
    be stationary. It would not always be lined up with
    any particular part of the dial. I've never seen this
    unit so I'm not sure what it looks like. It may have
    a fixed or movable pointer. If it has a fixed pointer,
    I'd think one would slow or speed up the watch to move
    the light to the pointer and then adjust it to be still.
    All this is assuming the motor runs on 60 Hz line
    and not that the ticking watch runs the motor in
    a phase looked loop.
    The ceramic caps are unlikely to be bad as you have
    said but carbon comp resistors are famous for being
    out of spec.
    How fast is the motor?
    Tinker Dwight
     
  9. Don Meyers

    Don Meyers Registered User

    Oct 30, 2010
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    Hi Tinker,

    The motor is a fixed speed 600 rpm. There is a metal disc mounted on an insulated sleeve on the shaft with one 1/2" long slit. Behind the slit is the neon light mounted to the disc. Contact with the light is by a stiff wire to the insulated sleeve of the motor and the disc. The clear dial face is fixed in the case and the metal disc with the neon light rotates behind it. The dial face also has lines running across the center every 10 degrees.

    Don
     
  10. Tinker Dwight

    Tinker Dwight Registered User

    Oct 11, 2010
    13,666
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    Calif. USA
    Hi Don
    This is kind of what I was assuming. The rotation of 600 RPM
    would be 10 rotations per second. That with 36 10 degree
    marks would be .002778 seconds per line. In
    other words, if the flash drifted across one line per minute,
    that would be .002778 seconds gained or lost per minute
    ( .1667 seconds per hour or 4 seconds per day ).
    You would most likely see two flashes at slightly different
    locations. One for the tick and one for the tock.
    You might check that there isn't a problem with the
    motor not running in sync. Holding it under an older florescent
    light should show it in stop action ( newer ones use high
    frequency and not 60Hz ). The brush for the
    lamp might be dragging to much or the bearings needing
    cleaning.
    I'd love to see a picture.
    Tinker Dwight
     
  11. Don Meyers

    Don Meyers Registered User

    Oct 30, 2010
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    I don't know how to post a picture on this site nor do I have a site to host the picture. I could send you pictures by email.

    Don
     
  12. Tinker Dwight

    Tinker Dwight Registered User

    Oct 11, 2010
    13,666
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    Calif. USA
    Hi
    Picture is not too hard. At the bottom of the message page,
    there is a button "Manage Attachments".
    I'll send you a PM message with my email address though.
    Tinker Dwight
     
  13. Tinker Dwight

    Tinker Dwight Registered User

    Oct 11, 2010
    13,666
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    Calif. USA
    Hi Don
    Looking at your past post again. I would think that
    when you turn the gain up too much, the 2D21 just
    goes in a free running mode. Its speed is likely controlled
    by the amount of turning the adjustment.
    My thinking is that you should be able to turn the adjustment
    down until the neon light doesn't flash. You'd then
    turn it up gradually until it just started to flash at the
    same rate as the ticks. With the disk spinning at speed,
    you should see the neon light at close to the same place
    on the dial but slowly moving fast or slow.
    If the gain is turned to high, the 2D21 just turns into
    a relaxation oscillator that isn't useful. There is probably
    a narrow band of gain that make the neon light flash
    synchronously with the watch.
    Do make sure your in a quiet environment. Radio, TV,
    heater blower and such should be a long way away.
    If you can't turn it down enough to get the neon light
    to turn off with no watch, you'll need to trouble shoot
    some.
    Tinker Dwight
     
  14. jimtone

    jimtone Registered User

    Dec 28, 2011
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    I have the same Precise Watch Timer and the microphone and amplifier circuit all work but the sychro motor and disc spin with the neon light not working/blinking. I tested for current with a multi meter set on DCV on 20 but got nothing at the pin socket where the plug connects the sychro motor and the speaker to the top side of the chassis. I didn't test under the chassis where the wires solder to the socket because I didn't have the chassis out of the case. I'm trying to determine what voltage to safely apply directly to the neon bulb to test if it works or not? I also don't have a schematic for this devise and can't find one online? The devise Model is "AC".
     
  15. flynwill

    flynwill Registered User
    NAWCC Member

    Feb 1, 2007
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    Rolling Hills Estates, CA
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    Most small Neon lamps take about 90V to start conducting, but once they do the current must be limited (typically with a resistor).
    Can you post a picture of this particular lamp? If is your common NE-2 bulb you can test it by connecting it directly to the 120 V AC mains with a 200k resistor in series. (But do be careful -- dangerous voltages).
    However these lamps are very robust and rarely fail other than by being physically broken, so I would say that's the least likely thing to be broken in the unit.
     

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