need help/coil

redwire

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Nov 14, 2010
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harrison ohio near cincinnati
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I found this kundo at an antique show at the local fair grounds I knew the battery was no good ,but at 1.5 volts I was sure I could make something fit when I opened the battery case there were six AA 's souldered together . after installing new batteries it still will not run? the coil has a resistance of 10ohms ,I understand there is more to the coil than just windings . Is there anyone out there that supplies or rebuilds this type of coil?
the clock is in good shape and I would like to have it working any help will be a great blessing thank you TOM
 

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Tinker Dwight

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Oct 11, 2010
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Calif. USA
Hi
There were two types of these. One had the
driver circuit in the base ( not to sure where ).
It may have actually been in the black box of the
battery:???:
The other had the driver circuit in the coil.
You first need to figure out which you have.
See several related resent threads:

need a little help with kundo
kundo electro-mechanical clock help
kundo electric-coil rewinding advice

Keep us informed on what you find.
Tinker Dwight
 

Tinker Dwight

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Oct 11, 2010
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Hi
There are some nice PDFs showing the two types
and some German text.

do a search for the heading:
kundo electric clock

It does show the schematic driver for the in coil type but
not for the external drive. It does show how the external
driver mounts relative to the battery.
Assuming that the battery in your picture is correct,
it should have the transistor inside the coil.
If there isn't s short someplace, the readings you have
would indicate a significant failure in the coil assembly.
As for the external driver circuit, there is a post out there
someplace that has the schematic for that as well but
you can look for it as well as I can.
Tinker Dwight
 

Scottie-TX

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Apr 6, 2004
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A D.C. resistance test of a coil tells little more than that it is open or not open. Low resistance - ten ohms - indicates your coil is not open and probably good.
The much bigger likelihood is that the transistor that supplies the pulse is D.O.A. (broke).
 

redwire

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Nov 14, 2010
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harrison ohio near cincinnati
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thank you for the replies dwhite/scotty i will open the case on the coil and get back to you .maybe today as I do have the coil removed just not opened.
I am not much good for electronics I am an electrician and used to a much larger scale of materials ? this is why I asked if it would better for me to replace the coil with a new or rebuilt one
however I will open the case and have a look see at this point I don't have anything to losse
 

Scottie-TX

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Your coil measures continuity so is probably good. Coils most often fail in an open condition. Seldom do they get "shorter" unless of course they went into meltdown and the insulation failed. I suspect that is not the case here as six cells woulda failed before the coil could reach meltdown.
 

harold bain

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You won't find any replacement parts for this clock, except from scrapped clocks. Opening up the coil might not be the best way to go yet. Are there any electronics elsewhere on the clock?
 

redwire

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Nov 14, 2010
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harrison ohio near cincinnati
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hello harold and every one ,the only electronics are in the coil case I did open it with some difficulty as the inner brass sleeve was peened pressed ?
after opening tried to send photos having camera problems.it's always something.the inside looks new but I know that can't be. I did find some info on this fourm from elliott sound products(rod elliott)said he has replaced the germanium transistor with a silicon type and it worked
I have a young friend who knows more about electronics than I :???::???::???::???:?I will try to get together with him soon to get his opinion
I will keep you posted on my findings. I do want to see this clock running as it is my first jeweled movement. I think the original transistor is the problem glass case germanium tf65 are not made any more. there is also a way to install the electronics in the base or so I have been told witch may need more voltage. anyhow in th meentime the brass needs cleanning thanks for all of your help I just love this place...........TOM
 

Scottie-TX

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Sounds like a man with a plan and I think you'll make it with your friend's assistance. I know I'd need it. Here: Here's a topic you may enjoy and help you consider alternatives as our friend I call "Pee-Tah" in the land down under, cleverly brought life back to his with an external - well - you read and enjoy: Pee-Tah's Folly
 

redwire

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Nov 14, 2010
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harrison ohio near cincinnati
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Thanks scotty I think peter is on to something here ?
I still think that someone should rebuild and sell the two types of coils for these clocks seems that there is a lot of need for them? wish I knew how I might get rich naw I'd end up giving them away...............TOM
 

t257daf

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Mar 22, 2004
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I see this thread is over 10 years old. I have a non-working Kundo electric. I am wondering if any developments have transpired over the years to get a Kundo Electric back into working condition. I'm not sure how to get the coil case open. Advice on safely opening the case would be welcome. If I can open the case, I think I could determine the condition of the coils. If coils OK, I would guess germanium transistor is the culprit. Is a substitute transistor available? If a coil is bad, are replacements available? Are Kundo coil repair services available? Any advice would be appreciated.

Don F
 

Schatznut

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Sep 26, 2020
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Here's the patent for the integrated magnetic motor. Replacement glass-cased germanium transistors are in fact available on the big auction site - they're used by stereo and vintage audio enthusiasts. Note this has two separate coils wound on the bobbin - a sense coil ("2" in the patent) and a drive coil ("3:). I recently rebuilt one of this type - one of the coils had opened up so I stripped off the old windings and rewound them. A fairly challenging job but ultimately successful. I can't tell from your photos, but this appears to be one of the movements with six jewels - this movement is a real beauty and well worth saving.

Kundo patent.png
 

t257daf

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Mar 22, 2004
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I've removed the coil from the mechanism. How do I open the casing around the coils? I'm not familiar with the big auction site. Do you have a location for it? Is there identification of transistor Model Number on the transistor? Thanks for your help and quick response.

Don Fagnan
 

Schatznut

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I believe you'll find there's a brass sleeve through the bore of the motor assembly that is swaged over the ends of the housing. You'll have to gently pry up the edges of the swaging using a hobby knife until you can grasp it with fine needle-nose pliers and work it loose. When you get it opened up, you'll need to measure the impedance of both coils. Because the resistor is wired across the drive coil, you'll need to isolate one end of the coil from the circuit to get a useful reading. My notes from a recent rebuild say the drive coil (3) should be about 1000 ohms and the sense coil (2) should be about 1650-1700 ohms. The resistor (5) is about 5.6kohms. The red dot on the transistor indicates the collector; the base lead is next to it and the emitter is the furthest away. The junction drop should be on the order of .2 to .3V. Note that none of these readings is particularly critical - as long as they're in the neighborhood (neither open nor shorted) they should be good. Search eBay for "glass germanium transistor" and you'll get a few hits. Since this transistor is being used as a switch instead in the linear region, it doesn't matter much which one you pick. Either the Philips or Mullard OC139 should work fine. Good luck and let us know what you find.
 
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t257daf

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Mar 22, 2004
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I got the can apart by prying up the swaged ends of the sleeve as you suggested. I was able to figure out which coil ends are which from the schematic. I unsoldered the resistor at the point where it connects to the collector and drive coil. All were soldered into a little spring which I could heat and slip out the resistor. The resistor is about 6k Ohms. Transistor tested OK at about .3 V. No. 2 Sensor coil measured 1.5K Ohms. No. 3 Drive coil is open. From your experience, how are the coils wound? Did you have to unwind both? Did you physically locate the open? Did you have to purchase new coil wire? The movement is a 6 jewel movement and case is in great shape. It belongs to a friend. I'd be willing to rewind.

Don F
 

Schatznut

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The windings are so fine - 42AWG - that just getting the insulating wrap off of the top coil was enough to break the wire in numerous places. The coils are wound one on top of the other - the sense coil first, a layer of insulation, and then the drive coil. I ended up just cutting the windings off with a utility knife and starting over from a bare spool. I put 5000 turns on the sense coil and 3000 turns on the drive coil. I have a drill press that will run at a very low speed with a turns counter on it, so I made a simple arbor for the spool. I bought magnet wire on eBay and tried my hand at it. The wire is so fine that it kept breaking just from the tension caused by the drag on the feed spool so I ended up equipping the feed spool with a couple of ball bearings, after which things started to go better. I still broke the wire a few times while getting the technique down, but ultimately was successful. I can't imagine doing this by hand!
 

t257daf

Registered User
Mar 22, 2004
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Sounds challenging! Of course, the open coil is under the good one. Not sure how I will procede. I presume you are not interested in doing another?
 

Schatznut

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Send me a PM and let's talk about it...
 

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