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Kundo Impulse purchase

Dave T

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Dec 8, 2011
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Stopped on my way home at a shop going out of business. Saw this sitting back in the corner all dusty and dirty.
Brought it home for $10 without even looking too hard at it. Figured I could have some fun trying to figure out why it wouldn't work. Couldn't get any reading on the coil, but did not show open??
So I finally tried a battery in it and it took right off! Cleaned up the glass dome, and haven't touched the rest of it yet. The hands are pinned, no nut? Wonder how old it is?
Kundo ten dollars.jpg Kundo ten dollars 1.jpg
 

Schatznut

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Nice find! Is this the zero-jewel or six-jewel movement? Is there a separate circuit card under the base or just a battery holder? Here's a copy of the US patent for the electromagnetic drive mechanism. Estimated date of manufacture would be between 1957-1967.
 

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Dave T

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It's a six jewel with just the battery holder.
Thanks for the pdf. I'll study it.
 

Dave T

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Les, I agree with you. I bought the clock assuming it wouldn't work, and just to have something to analyze and see what I could do with it.
Turns out, the clock runs fine but continues to gain a lot of time. I've adjusted the pendulum downward many turns now and it still runs fast. Beginning to wonder if it is just spinning on the pendulum rod?
I've studied the escape advance and I can't see that it is ever advancing more than one tooth at a time.

My only other experience with one of these is a Junghans ATO, and it was necessary to adjust the escape to avoid advancing two teeth at a time, and I've got it regulated real close now.

But this Kundo so far has me puzzled.
 

Dave T

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Adjusted the pendulum bob clear to the bottom as far as it will go. Still runs fast.
Obviously adjusting the pendulum has no effect. I have yet to adjust the escape mechanism. But I haven't caught it skipping two teeth.

And I tried to measure the resistance on the coil, but get no reading with a digital multimeter. Might try the old Simpson and see what it tells me.
 
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Dave T

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Aside from tearing open the coil, I'm about to the end of options on this one. The clock runs fine no matter what I do but continues to gain.
I'm using a Duracell 1.5V and currently have it sitting outside the clock base, to eliminate any influence in magnetic direction.
The pendulum has good swing and appears to have equal swing on both side. I've made sure the clock is level.
I've adjusted the pendulum up and down with no change. I've adjusted the click upward to the point it won't catch the escape wheel. And then run it back down to be sure to catch just one tooth.

Tried to measure tolerances in voltage and amps, but can't get any logical readings. (to me). And I'm in unqualified territory here. I've studied pdfs for the circuitry and instructions posted but can't get any readings that agree.

This model is the one with all the electrical inside the coil. I am wondering if the germanium transistor, (if it has one) could be out of tolerance and making the clock run fast?
Would like to continue to pursue this one just to learn and see if I can correct it, but don't know what to do next.
 

Schatznut

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Can you detect any evidence that the suspension spring has been replaced? The oscillation frequency is totally a product of the pendulum system and that spring is the only other variable besides position of the adjustment mass. The motor only gives it the impulse to cause it to run. If it is running at all there is nothing wrong with the motor and you can only make things worse by trying to open it up.
 
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Dave T

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That is good news, to me. I assumed that if it is running the electricals couldn't be an issue but wasn't sure about it.
Yes, I have looked at the suspension spring, and it looks all original to me and in good condition. There is an adjustment screw for it, but I haven't done anything with it and not sure what it's there for, or what to look for if I turn that screw.
 

Schatznut

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I guess at this point you've got nothing to lose but to adjust that screw and see what happens. Can you post a link to a video of the clock in motion? These clocks generate so much power that giving them even the slightest nudge with the pendulum at rest should cause it to gradually start building momentum until the escapement starts tripping.
 

Dave T

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Just took another look at that suspension spring, and as I said it looks fine. However..... I did see a problem with the other side of the escape wheel with what I call the drive wheel. Not sure what these parts are called, but the roller wheel riding on the adjacent wheel does not land in the same place every time.
You can tell by the way I write this I'm in foreign territory, but here's a video that shows what I'm trying to describe.
 
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Schatznut

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It is pretty erratic, and I think I saw at least one instance of its advancing by two teeth. You might take a slo-mo video to see what's going better.
 

Dave T

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I think you're right. I posted it on youtube, but can't remember how to slow it down.


 
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Schatznut

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If you're using an iPhone, there's a slo-mo feature in the camera. It will start recording at regular speed and then go to slo-mo after a few seconds.
 

Dave T

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Thanks, Found that option on my Android. I was trying to change it in Youtube, and couldn't find a way to do it.
So here's another video, not great but a little better. And according to what I see there is some aberration in that roller, but I don't think it's advancing more than one tooth at a time. Not sure yet.
 

Schatznut

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I'd back out the stop screw on the escapement lever by a scant 1/8 of a turn and see how it performs. In your first video, it definitely hangs up a couple of times. This is counterintuitive at this point, but once you get consistent operation you will have one less variable to battle.
 
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Dave T

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Screw backed out. We'll see what happens.
I do think it's not gaining as much now. But I'm not keeping a chart. But, I will as soon as it get a little closer to keeping time.
 
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