Well demonstrated and explained. Thanks. I have one, probably a later model, I bought within the past few months, but made sure it worked first before I bought it and took along batteries of various sizes to test the clock out.
I have one of these with pendulum switch. This is a true challenge to adjust the open/close states. I have been trying with a little clock module, however, not getting enough swing to keep time. I added a transistor stage with external battery and getting closer, yet, not there. I did enjoy your well developed and straightforward explanation. My coil impedance is 1200. This does keep me at the bench next to my HF rig.
Thank you so much for this video. Recently purchased a similar kundo electro mechanical clock at estate sale. Terminals for battery//cell were rusted away but wires were ok. Replaced terminals and plugged battery in..no luck. I thought the pendulum was frozen up. I watched your video and saw that you have to release the pendulum by unscrewing the transit screw. Excellent video!
Hi there Jerry. Glad the video was of some help. Alas, my 'clever fix' turned out useless, as after only about 3 days, the battery was used up. Whereas, a Kundo clock in original condition would probably have run for several *years* on one set of cells! Keep,up the good work, and best regards, Norman.
Really enjoyed that Norman - OC71's takes me back a few years. I remember saving up a couple of weeks pocket money to buy one - packed in a box the size of a matchbox. Also remember scraping the black paint of them and using them as photo transistors.
Hi there & thanks for writing. Yes - the old 'red spot' & 'blue spot' germanium transistors - my father had a shop that sold components & war surplus radio gear - so I got into messing around with that stuff & nearly 70 years later, it's still fun! Take care, Norman.
An ingenious workaround . I was very lucky with my Kundo clock . There was plenty of corrosion from the previous batteries but simply connecting the wire ends to an AAA battery with selotape it started working . It`s been running now for a few weeks . The corrosion on the negative contact caused some metal fatigue and trying to fit a new C battery the lug broke off. The metal was too brittle . I will tidy it all up with a soldering iron soon .Lovely concept for a clock though . Good video Thanks for the clever addition .
A Very clever solution for a common problem with this kind of clocks, congratulations! If the coil is Ok but the clock doesn't run it's because the transistor inside the coil, which acts as an electronic switch, is defective.
Before they adopted the transistorised version, the switching was done by a mechanical contact driven off the gathering pawl on the ratchet wheel driven by the pendulum. As the pendulum pawl drives the wheel around by one tooth, the gathering pawl has to rise up over a tooth and closes the contact. On the return swing the wheel doesn't move so the impulse is given only in one direction only. I have a working clock identical to yours, it keeps dreadful time. As you say the transistor circuit originally lived underneath the clock, where it is easily repaired, on later models it is hidden inside the coil housing.
Nice video! A clever and simple workaround. I'm tempted to try to reproduce this clock in Meccano. BTW I think maybe your grandparents had a Bulle Clock?
Neat workaround, I actually like it more with the electromechanical switch. Something else that may have worked as well would get the little circuit board from inside your regular cheap chinese quartz clock, desolder the coil of the clock motor, and put a full wave rectifier on it's place. The output of the rectifier then drives a transistor that switches on the pendulum coil.
@Oh!' Thinks me. 'Another technical video ratther than a disc/cylinder one'. Need I have worried? No! Thanks for yet another splendid video on subjects which would normally float way above my head. Here's to the next one.
good video friend, greetings from mexico, I have the same watch, with the same conditions your video helped me a lot, it also has transistors, I liked your idea, to use a mechanical switch, I still don't understand well how to close the circuit using the metal body of the watch, come on I don't get what polarity would be positive or negative? If I don't get it, I'll simply use a pair of wires from the positive pole ending in a pair of brushes that break the circuit when the pendulum swings to the left, in a very similar way to how you did. Thanks for sharing your knowledge.
My clock is still running well . The odd thing is , when the battery gets low the pendulum does not swing so far , and it starts to run faster . That `s when the battery needs changing ----after a very long time .
Norman, I know this is year old trade, but I just got similar one with rounded dome that I can't get it to work. Although I cleaned the corrosion and put new battery. Do you have any suggestions. Thanks
I have a very similar Kundo clock and I made new circuitry with one PNP and one NPN transistor which do the same job. No need for any mechanical changes. The principle is very simple when the magnet returns toward the middle position it induces a voltage in the coil, which opens one of the transistors, adding momentum to the pendulum through the second transistor. The Schematic isn't possible to attach here, but I know where you can find it: mb.nawcc.org/threads/parts-for-kundo-electronic.45991/
Hi there... well, in the model I had, the timing was purely dependent on the pendulum, as in traditional pendulum clocks; so there must be a way of *slightly* adjusting the length of the pendulum. If yours is running too fast, of course you have to very slightly lengthen it - then it will take that little bit longer for each swing, and get nearer showing the correct time. There are many models of this clock, and later ones may be controlled electronically. But the one in this video had the traditional adjustable length pendulum. Good Luck! Norman.
Was it a 50hz clock which you are using on 60Hz? No other reason for an electric clock to run fast - the power companies still count the cycles & adjust accordingly, so electric clocks will run true.
You can adjust the time faster or slower by turning the large brass cylinder on the pendulum. It is marked with a + and a - . Turn it in the direction you need to speed it up, + , or slow it down, - .
