Kundo 1960

Discussion in 'Electric Horology' started by ellll, Mar 8, 2006.

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  1. ellll

    ellll Guest

    Friends,

    I have a Kundo with the visible coil in the middle, and a curved magnetic pendulum,somewhat as seen on the ATO clocks, on the way to me. The case is perfect, which is the reason I accepted the clock. It is NOT running, but the man can't find anything wrong....(!), and knows nothing about clocks, or electronics... Just to get a "jump" on things, a few questions:

    Is it transistor control if 1960 by Kundo? I have only one photo, but it clearly shows the same escapement as used on the ATO clocks...

    If so, and a modern transistor is used for replacement, (Or for any other clock, inc. the Schatz for that matter), why not use one of the cells of some 2 to 8 or more volts that are made for applications in modern solid state, and are commonly available in different shapes/sizes,(as in photog, for example, and some small energy hungry handhelds etc...and childs games..There are a lot of new electronic cells out there..).

    Would that not give sufficient voltage/amperage to operate the modern transistor for clock use? Perhaps really what I am asking is what battery would equal the level mentioned on other threads, for a silicon transistor to switch?

    My Regards, John (ellll)
     
  2. ellll

    ellll Guest

    Friends,

    I have a Kundo with the visible coil in the middle, and a curved magnetic pendulum,somewhat as seen on the ATO clocks, on the way to me. The case is perfect, which is the reason I accepted the clock. It is NOT running, but the man can't find anything wrong....(!), and knows nothing about clocks, or electronics... Just to get a "jump" on things, a few questions:

    Is it transistor control if 1960 by Kundo? I have only one photo, but it clearly shows the same escapement as used on the ATO clocks...

    If so, and a modern transistor is used for replacement, (Or for any other clock, inc. the Schatz for that matter), why not use one of the cells of some 2 to 8 or more volts that are made for applications in modern solid state, and are commonly available in different shapes/sizes,(as in photog, for example, and some small energy hungry handhelds etc...and childs games..There are a lot of new electronic cells out there..).

    Would that not give sufficient voltage/amperage to operate the modern transistor for clock use? Perhaps really what I am asking is what battery would equal the level mentioned on other threads, for a silicon transistor to switch?

    My Regards, John (ellll)
     
  3. harold bain

    harold bain Registered User
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    Hi, John. The transistor is only a switch. Increasing the voltage would only burn out your coil. These clocks work quite well when everything is right with them. Check previous posts to find some modern equivalent transistors for replacement if needed. You will need an analog meter to check the coil before getting any further into it. If you are lucky, the battery terminals will be corroded, and cleaning them will make it work.
    Harold
     
  4. Bob Pritzker

    Bob Pritzker Registered User

    Jan 20, 2005
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    Hi John
    To answer two of your questions. The clock is likely to be traqnsistor controlled since ATO gave Junghans the right to manufacture these clocks and ATO patented the transistor switch for their clocks in 1953. Typically these clocks work on 1.5V. Timesavers show a battery that is a replacement for the one that originally worked in these clocks. They also offer an adapter that shows two cells which (I think) are connected in parallel. I would think, therefore that the issue is more likely one of amperage than voltage. I definitely would try Harold's suggestions first. My limited experience with these impulsed electric clocks is that corrosion and dirt prevent the current flow in almost all the cases and this keeps them from working. In fact, the reason why Lavet developed the transistor switch was to prevent the contact points in mechanical switches from pitting. Good luck. Bob
     
  5. ellll

    ellll Guest

    Thanks for kind answers,

    Actually, I was also interested in the different values that may allow a limited additional volts/amps/res. that would work the silicon transistor well, yet not endanger any coils...Many different clocks need something to run the silicon, as they are plentiful, and the original germanium are not...

    I know that a few years ago Radio Shack had a HUGH assortment of very low voltage dry cells, (and also modern alkaline and lithium cells etc), which would allow options...Don't know what they might have today..Keep meaning to go down and pick up a catalog....

    In any event, we will determine why this one won't run in a few days;... It will be here...and in fact, I WILL hope it is just a bit 'o corrosion somewhere...Will give the answer right here!!!

    My Regards, John
     
  6. ellll

    ellll Guest

    Never Mind!!,

    After reading the topic of "shipping across the pond..."...Make that another few weeks.NOT days...(before it arrives..It is coming from UK..)

    John
     
  7. DC Kelley

    DC Kelley Registered User

    Mar 16, 2006
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    Wait until you see your "new" Kundo before you worry about transistors

    You may not in fact have ANY transistors. There seems to have been a short period of time after the contact switch design was abandoned where they used what today we would call a magnetic reed switch buried along the end of the drive coil. This was momentary closed by the action of the magnet in the pendulum passing by on the down swing and energized the coil. All you see is two wires which connect to the battery. My father, who owns one of this style called it "litz" wire (and runs an AA battery rather then the old original cell in his) say it is also polarity sensitive (will not work if battery is reversed) which indicated to me there is a diode in there, but I have never seen the actual circuit diagram. [And I very much defer to the professional expertise of others here, I just play with clocks]


    I have always had a sweet spot for the Kundo clock, having one in the house I grew up in. I have two of them coming to me next week, one with old battery and the reed switch design one with a C cell and transistors. Lets compare notes when we get our new toys, but the worst case of replacement of the transistor design is still a simple thing to do (I am an EE by trade) and easily overcome.
     
  8. ellll

    ellll Guest

    Still waiting on the arrival of this timepiece..

    Regards, John
     
  9. DC Kelley

    DC Kelley Registered User

    Mar 16, 2006
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    Well the first two of my own have come in now, nether has transistors. One has the old style battery (type 6,7,8?) and the other has a plastic compartment in the same cavity marked Kundo-Germany in the molding and holding a C size battery. I have one other one coming and it does have transistors. I've ordered a battery convertor, and both other these need a really good soak in the company's ultrasonic tank to look pretty again. When they al all three ruining again I will set an oscilloscope on them and see what mysteries might be hidden in that coil.
     
  10. Mike Phelan

    Mike Phelan Registered User

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    A few points here:
    Germanium transistors typically need 0.25 volts to turn the base-emitter junction on. Silicon ones 0.7 volts. So, there may be circuit modifications needed.

    Germanium transistors do not like any heat, and start to leak (thermal runaway).

    Those in metal cases also exhibit the infamous "tin whiskers" as NASA found to their chagrin.

    Increasing the battery voltage will increase the current through the coil, which may cook it.

    The parallel batteries suggested will be to give a longer life - there should not be any need for more "amperage" (the term is "current") here, as the duty cycle of the coil is probably less than 50%

    Clocks with contacts that do not use a transistor can reduce sparking at the contacts (the 1.5 volts from the battery can typically give a 50 volt spark :eek:) by putting a diode across the coil. Smiths did this on the later car clocks.

    HTH
     
  11. ellll

    ellll Guest

    Thanks to Mike for the excellent content he provided reminding of latent electrical energy in a coil..sometimes producing surprising energy back out...I recall a design an eng. friend made for a device that would knock you half off your feet...

    I am MOST interested that the diode was used by Smiths to avoid this contact trouble, and recall reading of many items using some protection for this excess energy, on the "contacts" of one kind or another........(I am just recently getting interested in the electric clocks...)

    By The way...The man I am getting the clock from has my money...BUT..(unknown to me..) he held off on shipping the clock 'till this week, as he had to go over to the continent on a trip..(He is in UK..He has it ready and will send it tomorrow...) Personally I think he should have sent it before heading for France...but ...Oh Well...)

    Regards, John
     
  12. ellll

    ellll Guest

    Friends,

    Out of pocket for a month or so...but wanted to mention;

    The prob. with the Kundo Electronic, when I finally got it....was loose + lead at batt. bx, NOT the transistor...Good lesson for worrying about things "ahead" of time......It's fine now.

    Again many thanks for the kind answers...

    John (ellll)
     
  13. harold bain

    harold bain Registered User
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    John, glad to hear your problem was minor. About 80 % of the electric clocks I repair have loose or dirty battery contacts causing the problem. :biggrin:
    Harold
     
  14. ellll

    ellll Guest

    Hi Harold,

    Many thanks for the kind reply!!..As I said, worry about a problem before actually seeing it in person, never seems a good policy....

    Perhaps I will learn,..or just not chance the "needy" unit...(but those are the ones that always attract my attention, for some reason :rolleyes:..)!!!

    Regards, John
     
  15. ellll

    ellll Guest

    Hi Mr. Kelly,

    Yes, as you might notice above...Loose wire.. :rolleyes: I will learn to not attempt diagnosis from afar...maybe...

    In the meantime, I MEAN to get a site for doing photos sometime soon...and will do a photo. I will say, I have not seen this model before, and I have seen a number of batt. clocks...It is no treasure (except to me...), but is interesting..

    Perhaps we will be in touch again, and may I thank you for your kind multiple replys!! (Sorry I am late on that...The old mind wanders at times, I fear...)

    My Regards, John
     
  16. DC Kelley

    DC Kelley Registered User

    Mar 16, 2006
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    ellll Good to hear from you again and hope your new Kundo gives years of satisfaction.

    I want to revise my prior statements about Kundo using a magnetic trigger (a micro switch), I have read elsewhere on this forum that the single transistor can be buried inside the coil assembly. I am not sure I am right on that. I will take the buried transistor on faith, but do not see how you could hide an electrolytic capacitor (needed for the tank circuit) in there too. I have two now (Kundo and ATO) with the double transistor design externally mounted in the base. Others show only the coil.

    I now have seven of the damn things (trying to build a collection of their evolution from ATO to the cheap plastic ones) and so far none had any problems with the coils or transistors. A couple had corrosion issues. Kind of disappointing, I was wanting an excuse to tear into one and reverse engineer the circuit. Other then aggressive cleaning, I am reluctant to damage a working clock. I will hang a scope on them and explore, but my 9~5 life is a bit busy right now.

    Here is quick snapshot that does not do the group justice, need to build a shelf and need to clean all these things, so far they have just been set up and run. Cluttering up my office, wife comes in and wonders if I have gone mad. An interesting side note is the harmonic vibration of seven pendulums at the same rate does not seem to bother them, but it gives the ATMOS in the middle a bit of trouble. When I get the time I will do a proper set of pictures and turn this into a forensic review of the different models and evolution.

    Some kundos
     
  17. Mike Phelan

    Mike Phelan Registered User

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    Hi DC
    Nice collection! You could not really get an electrolytic in the coil, not even a modern one, but it is possible not to have one, if the battery capacity was sufficient to give enough of a current pulse to drive the clock.
     
  18. John Hubby

    John Hubby Senior Administrator Emeritus
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    DC, very nice collection!

    I didn't see any of the mechanically switched models in your collection. Is there one? If not I can provide photos of three of the versions that I have in my collection.

    The "next" version after that to my knowledge is the one where they went electronic with all the circuitry mounted on a board that was part of the plastic battery holder.

    Then, they put it all inside the coil. I have one of those with "all" the circuitry components inside the coil housing. I have to presume the transistor, diode, etc are all there since I haven't taken it apart. The only external electrical parts are the two wires going to the battery holder, the holder itself, and the battery.

    John Hubby
     
  19. skruft

    skruft Registered User
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    Let me ask a basic question! I do not collect this type of clock but do have a similar one that is marked "Junghans ATO" and "Made in Germany." It runs perfectly, but is quite fast and I do not know how to slow it down. Can you explain how this is done?
     
  20. eskmill

    eskmill Registered User
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    Skruft I've replied to your query with a new thread, "Junghans ATO Made in Germany."
     
  21. DC Kelley

    DC Kelley Registered User

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    #21 DC Kelley, Apr 28, 2006
    Last edited by a moderator: Dec 30, 2016
    Yes please. I would love to get a complete evolution documented, if not a personal collection. The mech contact switched ones are, as you note, harder to come by. ATO seems to hold its used value better as well.

    I am not sure when this clock was discontinued, but the "last" model seem to be in the early '70s with a 3-sides plastic dome on a black plastic base. Same basic works, no jewels. More sold in the UK then here, I presume Kundo distribution died but do not know any details.
     
  22. roughbarked

    roughbarked Registered User

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    The mind doesn't have to be old to wander. ;)

    I have one of these Kundo's to repair at the moment. The coil tests with good resistance, so I assume I'm going to have to pull the cover off the coil unit and see what is inside.
     
  23. Tinker Dwight

    Tinker Dwight Registered User

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    Are you talking about a transistor one?
    The transistor model's coils can not be tested
    from the outside with a meter.
    There are two separate coils that need to be checked
    inside.
    Do you have an external transistor type with a board
    in the base or the type with the internal transistor
    in the coil assembly?
    If it is the internal coil type, here is what I know so far.
    I've just opened one up and can explain the process.
    The tube in the center has been flared at both ends
    You need to work with a sharp edge and fold the flare
    up gradually until it clears the cover and slides through the
    coil.
    A real pain as these were not intended to be worked on.
    I believe the problem is the cloth covered wire used.
    On the one I'm looking at now, one can see corroded
    coil wire here the cloth covered wire was sitting on it.
    It is possible that it may have been potassium hydroxide
    from a leaky alkaline cell. It will wick up cloth or even stranded
    wire and cause all kinds of problems at the other end.
    Nasty stuff!
    Tinker Dwight
     
  24. roughbarked

    roughbarked Registered User

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    I'm talking about one of the later models. So presumably it has the transistor. Yes, it does look like the only way into the coils is by prising the casing open.
     
  25. roughbarked

    roughbarked Registered User

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  26. Tinker Dwight

    Tinker Dwight Registered User

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    The coil was intact but likely this was either a failure of the sense
    coil or the transistor.
    His fix was not what I'd call the right way to do it.
    Tinker Dwight

    - - - Updated - - -


    Use care, many have trashed the covers by not releasing the center
    part.
    Tinker Dwight
     
  27. roughbarked

    roughbarked Registered User

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    Yes. Thanks. It does look to be an all care type job.
     
  28. Tinker Dwight

    Tinker Dwight Registered User

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    An option might be to use a moto tool with a burr and cut a ring around
    the inner tube to separate the two halves. Not a nice but easier.
    To reassemble, a little locktite or such the hold the tubes pieces in the
    plastic coil bobbin. It is not likely to show from the outside as the pendulum
    will be in the way.
    It might be a cleaner fix than trying to unflare the tube.
    Tinker Dwight
     
  29. joerg-ehlen

    joerg-ehlen Registered User

    Jan 12, 2008
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    Hi, just a few informations:

    The coil of the Kundo has two windings. One between base and emitter of the germanium transistor, the other one between collector and battery supply. Both windings have resistances in the range of kilo ohms. When I remember right, they use very fine enamelled cooper wire. 0.08 mm. The collector coil has several thousand turns. See
    http://sound.whsites.net/clocks/kundo.html
    Germanium transistors are still available in small quantities at some online distributor shops. It should be a transistor with plastic or glass case because the metal case is magnetic and ca lead to wobble of the pendulum.

    A diode at the coil should never be used. The coil not only attracts the magnet. The magnet also induces voltages into the coil when the pendulum swings. If a diode as over-voltage protection is added to the circuit, diode will also short-circuit these induced voltages with the result that additional damping of the pendulum occurs. Semiconductors also have a strong temperature effect. as long as the transistor just acts as switch, this temperature effect an be neglected. But the diode has a higher saturation voltage than the base-collector circuit of the transistor. Because of this, the influence of the diode to the damping of the pendulum also has a bad influence to the temperature stability of the clock.

    Diodes as over voltage protection should generally not used in electric horology, because the diode not only suppresses overvoltages. Instead of overvoltage, the diode discharges the magnetic energy of the coil by making a kind of short-circuit. The problem is the additional current which flows in this situation. It can take several hundred milliseconds. until this current disappears. In time critical circuits this additional current should be avoided. You can check the influence of the diode on the timing when you switch a relays with and without over voltage protection by a diode. You will notice that the relays trips immediately after the circuit is interrupted when no diode is there. But with diode you will notice that the relais trips with a significant delay.
    Alternative to diodes, the classic resistor with 10 times the DC resistance of the coil can be used, or varistors with low voltage rating.
     
  30. joerg-ehlen

    joerg-ehlen Registered User

    Jan 12, 2008
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    You can open the brass case of the coil when you bent the sleeve of the inner brass cylinder of the brass case. This cylinder acts as a kind of rivet.
     
  31. Tinker Dwight

    Tinker Dwight Registered User

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    Ok, I'll admit, I just did a rewind of one. I used some care to
    unfold the flared end of the tube. Still, it was not a clean job. A couple times
    the edge I used scratched the end of the cover. While it is possible to
    fold the flare up, it is not a clean job. Close inspection one can see
    it does not lie back down smoothly either.
    Should I do another, I will cut the inside of the tube and use glue to
    put it back together rather than mess with the flared ends.
    It will work just as well and be a lot easier to repair. The cut of the
    tubing will not be very visible once assembled in the clock. It will look
    much cleaner than working the flare.
    I had no issues winding the wire, using my homemade wire spool
    regulator. The wire is tiny. Even with my glasses, I had a hard time
    locating it when I let an end go.
    I suspect most failures are related to the coil. I did not have to replace
    the transistor that worked fine. The wire that they used for interconnections
    decayed and rotted the winding wires. I chose to use Litz wire, keeping with
    the small size of things. The connection of the magnet wire and
    Litz wire had much less stress.
    I only had one color wire but found it easy to determine the polarity of the
    coils with a transistor VTVM and a small magnet. It was easy to determine
    the correct connections, relative to the battery and transistor by watching
    which way the meter reacted to the moving magnet.
    Tinker Dwight
     
  32. joerg-ehlen

    joerg-ehlen Registered User

    Jan 12, 2008
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    Hi, yes. But when you glue the tube, nobody else in the future has a chance to repair it again. That's the general disadvantage of glue.
     
  33. Burkhard Rasch

    Burkhard Rasch Registered User
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  34. Tinker Dwight

    Tinker Dwight Registered User

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    #34 Tinker Dwight, Dec 30, 2016
    Last edited: Dec 30, 2016
    That really depends on the glue or adhesive used.
    I'm not sure which would melt first, hot glue or the bobbin?
    Also something like double sided tape is an option.
    I doubt one could bend the brass tubing more than once
    without fracturing it.
    One still has the option of bending the flared ends to get the
    covers off.
    If I had replacement tubing and a jug to flare the ends, that
    would be optimal.
    Tinker Dwight
     
  35. roughbarked

    roughbarked Registered User

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    It is a reasonably tight fit anyway. I'd reckon only a few dots of five minute epoxy will hold it in place and these will come unstuck from the heat of a match.
     

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