Into a Bulle this time

Discussion in 'Electric Horology' started by mopydick, Oct 24, 2016.

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  1. mopydick

    mopydick Registered User

    Jul 12, 2016
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    It runs but very lethargic. Its very dirty so it may be just the mechanics that are gummed up so I'm going after them first. Although I suspect that the magnetic is going to be the ultimate issue. I say this because the voltage across the coil looks pretty good on the oscilloscope (clean switching and repeatable). And the coil resistance is 1.2 kOhm.

    In the pix below, the red arrow is pointing to a spring that has no apparent use. It's tied between a fixed end arm in space, and the center pin of the toggling Y thing. Both seem very fixed to the brass plates. Is this is where this belongs? Or did someone install in incorrectly in the past?

    Also, some of the nut/screw heads (in the red boxes) are new to me. Should I grind a center slot in a screwdriver to mate with these curious fasteners? Or is there a source to purchase an assortment of this type of screwdriver?

    Finally, I assume that I need to be extra careful cleaning this movement. I use Zenith Formula 67 cleaning solution which seems to be fairly aggressive (it only takes a couple of minutes to remove any tarnish from brass). If some insulation material got into the cleaner, I bet it would disappear pretty quickly.

    As usual, thank you in advance for your thoughts,

    Peter

    1.jpg
     
  2. tickntock1

    tickntock1 Registered User
    NAWCC Member

    Feb 27, 2002
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    The spring has to be there since it is the pathway of the electricity into the fork so that there's a completed circuit to energize the coil when the pin makes contact with the uninsulated side of the fork. Be careful with the spring as it's made out of silver.
    jim
     
  3. sophiebear0_0

    sophiebear0_0 Registered User

    Nov 5, 2012
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    Peter

    As Jim points out the silver contact spring is there to provide a reliable electrical contact. There is an electrical path via the arbor and frame, but sometimes this can develop additional electrical resistance (oil, dirt etc) and hence the contact spring should be there to provide a reliable low resistance path. To achieve this the spring must be perfectly clean - and also should be attached at low tension so that it just rolls over the stud on the fork.

    I use a small screwdriver with a filed slot to tackle the special nuts. You can use round-nosed pliers for nuts that are difficult to remove, but be careful not to split the nuts. There are pretty fragile.

    You will find a wealth of information on the www.horologix.com website, as well as on this site.

    Regards,

    Peter
     
  4. mopydick

    mopydick Registered User

    Jul 12, 2016
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    Thanks for the info, especially on Horologix - what a resource. Just from reading the first article on a restoration, it suggested pulsing the coil manually as a base check. And in my case, it demonstrated the there is nothing wrong with my coil or permanent magnet (see video).

    As to the silver spring - mine is absolutely black from tarnish. I assume that I should give this a good soaking the cleaner to restore its surface to pure silver to maximize conductivity at the contact points.

    Also, I found a place on Ebay that sells the so called 'spanner screwdrivers' with the slots precut. I'll wait until they come in before moving on the movement any further.

    Thanks everybody!

    Peter


    [video]http://vid544.photobucket.com/albums/hh349/thurmondvanripper/1025161024_zpskmpg2cuv.mp4[/video]
     
  5. sophiebear0_0

    sophiebear0_0 Registered User

    Nov 5, 2012
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    Peter

    The spring should clean up ok. If not it is easy enough to wind a new one from silver wire. The key issue with the contact spring is to make sure that they do not add friction to the button behind the fork. They should just roll to provide electrical conductivity.

    You also need to make sure the silver contact on the fork and the silver contact pin are squeaky clean. You should be able to measure the resitance when the clock is running to make sure that the system resitance is close to the coil resitance (usually around 1200 ohms).

    From your description it does seem that once your clean the movement you will be in better shape. One thing to look out for is to make sure that the end stop that sits above the contrate wheel has sufficient clearance to allow the wheel to rotate freely. Sometimes this drops down and can add unwanted friction. You will probably need your spanner screwdriver to re-position the end stop.

    Good luck.

    Peter
     

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