Kern and Sohne Battery Powered Clock

gspotjulian

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If the goal is to get the clock running, why worry about the diode? It's a non-factory modification that someone thought it needed. If you find arcing a problem once the clock is running you should explore solutions but until then it's a wasted effort.

Just a thought.

Eric
This was more a comment to Kurt as he was questioning the diode. I am just going to fit a 3v battery and see what happens.
 
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Cheezhead

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A bit of arcing is good to help keep a clean contact suface so the diode might not be advisable to prevent arcing unless the contacts are gold flashed. Then you want no arcing to burn through the thin layer of gold. 3 volts is very low and may later not be able to puncture through oxidation or contamination on the contact surfaces where they touch. If the contacts have a wiping motion as they close, that is good.
 

gspotjulian

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A bit of arcing is good to help keep a clean contact suface so the diode might not be advisable to prevent arcing unless the contacts are gold flashed. Then you want no arcing to burn through the thin layer of gold. 3 volts is very low and may later not be able to puncture through oxidation or contamination on the contact surfaces where they touch. If the contacts have a wiping motion as they close, that is good.
Thanks for the advice, if the clock works when I put the batteries in then great. thanks for the tip. Julian
 

gspotjulian

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Hi Guys,
back again, well I fitted two 1.5v batteries and a battery holder to the base, gave the 4 rotating balls some encouragement and waited, nothing happened and the clock does not work off battery. I have looked at the clock workings and when the 4 balls are rotating all the mechanisms work and the hands move but as soon as the momentum goes out of the 4 balls everything stops.
I have a couple of questions and I am a total novice on clocks but am an automotive engineer.
I have posted a pic here, what is this "lever" for, sometimes it clicks and moves.
Where are the contacts that everyone says should be cleaned as maybe this is the problem. How do I dismantle to get to them?
If anyone can help, I'd be appreciative but remember I am a novice and you may know these clocks inside out but this is the first time I have seen or handled one.
Thanks, Julian Clock 3.jpg Clock 4.jpg
 

KurtinSA

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Have you confirmed 3v at where the wires come into the movement? I think the "lever" you're referring to is the arm with a weight at the end of it. As I understand it, this lever provides the push to move the center arbor wheel at each tick-tock of the pendulum rotation. It's using gravity to pull the lever down and push against the teeth on the wheel. Once the lever gets low enough to trigger the relay, there is a louder snap and the lever is pushed back to the top again so it can start its downward movement. I would manually keep the pendulum rotating and watch that the weight keeps moving down. See if you can get the weight low enough to actuate the relay...if it doesn't kick the lever up, then it might begin to bind or something. You say the hands are moving, so that suggests that the lever is dropping to turn the wheel.

On this mechanism, there is a screw that is probably used as a stop to keep the arm from going too far. Could be that this screw is turned in too far and is not allowing the lever to drop?

Kurt
 
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gspotjulian

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Have you confirmed 3v at where the wires come into the movement? I think the "lever" you're referring to is the arm with a weight at the end of it. As I understand it, this lever provides the push to move the center arbor wheel at each tick-tock of the pendulum rotation. It's using gravity to pull the lever down and push against the teeth on the wheel. Once the lever gets low enough to trigger the relay, there is a louder snap and the lever is pushed back to the top again so it can start its downward movement. I would manually keep the pendulum rotating and watch that the weight keeps moving down. See if you can get the weight low enough to actuate the relay...if it doesn't kick the lever up, then it might begin to bind or something. You say the hands are moving, so that suggests that the lever is dropping to turn the wheel.

On this mechanism, there is a screw that is probably used as a stop to keep the arm from going too far. Could be that this screw is turned in too far and is not allowing the lever to drop?

Kurt
I have now confirmed that I have 3.15v into the clock. If I use the red probe of the multi meter and touch any of the screws on the central block, with the black probe earthed I get 3.15v. The stop screw has not been moved. What else can I try. Can it be the contacts need cleaning, if so where are they and how do I get to them? Any help would be appreciated. Julian
 

gspotjulian

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I have now confirmed that I have 3.15v into the clock. If I use the red probe of the multi meter and touch any of the screws on the central block, with the black probe earthed I get 3.15v. The stop screw has not been moved. What else can I try. Can it be the contacts need cleaning, if so where are they and how do I get to them? Any help would be appreciated. Julian
 

Wayne A

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As long as the weight arm is not at the bottom of the clock the solenoid contacts will not close. Power for the movement comes entirely from the weighted arm you ask whats this lever for in Post #54. So if the clock will not run with arm up its not an electrical issue.

Wayne
 

gspotjulian

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As long as the weight arm is not at the bottom of the clock the solenoid contacts will not close. Power for the movement comes entirely from the weighted arm you ask whats this lever for in Post #54. So if the clock will not run with arm up its not an electrical issue.

Wayne
So another dead end. When the 4 balls are rotating all the mechanisms work and the hands move but as soon as the momentum goes out of the 4 balls everything stops. If I have power there and the mechanism works why does it not run? the mechanism looks clean, no dust / grit?
Am I starting the clock correctly by removing the restraint on the rotational 4 balls and applying a slight manual rotation or does it start on it's own? Julian
 

gspotjulian

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So another dead end. When the 4 balls are rotating all the mechanisms work and the hands move but as soon as the momentum goes out of the 4 balls everything stops. If I have power there and the mechanism works why does it not run? the mechanism looks clean, no dust / grit?
Am I starting the clock correctly by removing the restraint on the rotational 4 balls and applying a slight manual rotation or does it start on it's own? Julian
 

Wayne A

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Sounds like your clock needs servicing and its the first thing I do to new to me clocks even if they run on arrival which is quite a rare thing.

The clock does not start by itself and you would make a 180deg turn on the pendulum and let it go. You should see be able to see the escapement operate as the pendulum swings.

Wayne
 

gspotjulian

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Sounds like your clock needs servicing and its the first thing I do to new to me clocks even if they run on arrival which is quite a rare thing.

The clock does not start by itself and you would make a 180deg turn on the pendulum and let it go. You should see be able to see the escapement operate as the pendulum swings.

Wayne
I gave the gearing a meagre spray of light oil WD40 and a 180 degree motivational turn of the pendulum and it stops after a while. Everything works when it is in momentum and the eventually grinds to a halt. i'm stumped now, anyone wanna buy it lol
 

KurtinSA

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So, Julian, when the pendulum is going, do you see the small weight on the end of the lever dropping? When it gets to some trigger point near the bottom, that's when the relay contacts engage and the lever is pushed back to the top. If the lever never gets pushed back up, then there must be something that is preventing the triggering, either mechanically or electrically preventing it.

Kurt
 

gspotjulian

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Have you checked the usual mechanical side of it? Is it in beat? Have you disassembled and cleaned?

When the 4 balls are rotating all the mechanisms work and the hands move but as soon as the momentum goes out of the 4 balls everything stops. If I have power there and the mechanism works why does it not run? the mechanism looks clean, no dust / grit?
 

gspotjulian

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[QUOTE IMG_7923.JPG ="KurtinSA, post: 1477983, member: 68514"]
So, Julian, when the pendulum is going, do you see the small weight on the end of the lever dropping? When it gets to some trigger point near the bottom, that's when the relay contacts engage and the lever is pushed back to the top. If the lever never gets pushed back up, then there must be something that is preventing the triggering, either mechanically or electrically preventing it.

Kurt
[/QUOTE]
Hi Kurt, Do you mean this weight on this lever?
 

Wayne A

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Perhaps posting a video of the clock movement as you give it a 180deg turn would help us. That weight should fall slightly at every turn of the escapement as its the power source. Typically the weighted arm drives the movement through a one way clutch, you should be able to raise the weight by hand.
This VIDEO shows a clock that uses a weighted arm to power the movement. Its a different style clock, different escapement too but you get the idea what the motion of the weight should look like. As the pendulum rotates the arm falls, when the arm reaches the bottom it hits the electrical contact that energizes the solenoid to raise the weighted arm. Clock will not run if the weight remains at the bottom.

Wayne
 

KurtinSA

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Julian -

Wayne is spot on with that video...that is what is expected to happen when things are working correctly, both mechanically and electrically.

Kurt
 

gspotjulian

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Perhaps posting a video of the clock movement as you give it a 180deg turn would help us. That weight should fall slightly at every turn of the escapement as its the power source. Typically the weighted arm drives the movement through a one way clutch, you should be able to raise the weight by hand.
This VIDEO shows a clock that uses a weighted arm to power the movement. Its a different style clock, different escapement too but you get the idea what the motion of the weight should look like. As the pendulum rotates the arm falls, when the arm reaches the bottom it hits the electrical contact that energizes the solenoid to raise the weighted arm. Clock will not run if the weight remains at the bottom.

Wayne
Hi Wayne, Video, blimey that's modern, I don't use a smart phone, but thanks for the video link I see now how it is supposed to look when running. Rightly or wrongly - see pic - I have replicated the movement by moving this pin back and forth as it does when it runs. The weight drops slowly but does not come back up. If I move the lower plate upwards the drop arm weight clicks back to the top see lower arrow. Julian IMG_7923.JPG
 

Wayne A

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The weight drops slowly but does not come back up. If I move the lower plate upwards the drop arm weight clicks back to the top see lower arrow.
Well its one of two things, the contact is not actually closing or there is another electrical issue present that prevents the solenoid from energizing. You have to look for the contact and see if it is actually closing, and its also possible that there is carbon or dirt present that prevents current flow.

Also when you manually press the solenoid lever it should raise the weight as you indicate.

Wayne
 

gspotjulian

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Well its one of two things, the contact is not actually closing or there is another electrical issue present that prevents the solenoid from energizing. You have to look for the contact and see if it is actually closing, and its also possible that there is carbon or dirt present that prevents current flow.

Also when you manually press the solenoid lever it should raise the weight as you indicate.

Wayne
If you look at the photo I posted with the two arrows, are the contacts under the plate of the lower arrow as I see no contacts anywhere? Julian
 

KurtinSA

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Julian -

I've relooked at my clock and will offer what I see.

1) the lever with the weight moves down from the beats of the clock.
2) the lever is a 90 arm and one part of that arm has a set screw on it.
3) as the lever moves down, that set screw moves closer and closer to a "pad" which I believe are the contacts.
4) when the set screw contacts that pad, the circuit is closed and the coil below energizes which creates a magnetic field
5) the magnetic field pulls the plate down...this is the plate at your lower arrow
6) as that plate comes down, it kicks the lever back up
7) there is a spring on the far side of the coil area that pulls the plate back down on that side, which pulls the plate up on the opposite side...this serves to break the contacts and the coil is de-energized
8) the process repeats

On my clock, the part that your lower area points to shows the tabs up near the top of the slots on my clock...your picture shows the tabs in the middle somewhere. The lever with weight on my clock is all the way at the top like your picture. So, I'm wondering if something is out of position on your clock. Like that small set screw. Maybe the return spring on the far side is broken or bent.

Let us know if any of this makes sense. It does to me...but then I'm often wrong!!

Kurt
 

gspotjulian

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Julian -

I've relooked at my clock and will offer what I see.

1) the lever with the weight moves down from the beats of the clock.
2) the lever is a 90 arm and one part of that arm has a set screw on it.
3) as the lever moves down, that set screw moves closer and closer to a "pad" which I believe are the contacts.
4) when the set screw contacts that pad, the circuit is closed and the coil below energizes which creates a magnetic field
5) the magnetic field pulls the plate down...this is the plate at your lower arrow
6) as that plate comes down, it kicks the lever back up
7) there is a spring on the far side of the coil area that pulls the plate back down on that side, which pulls the plate up on the opposite side...this serves to break the contacts and the coil is de-energized
8) the process repeats

On my clock, the part that your lower area points to shows the tabs up near the top of the slots on my clock...your picture shows the tabs in the middle somewhere. The lever with weight on my clock is all the way at the top like your picture. So, I'm wondering if something is out of position on your clock. Like that small set screw. Maybe the return spring on the far side is broken or bent.

Let us know if any of this makes sense. It does to me...but then I'm often wrong!!

Kurt
Hi Kurt,
Thanks for all the info, it makes perfect sense, I'll check it all out and let you know - Julian
 

gspotjulian

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Hi Guy's,
I have found a couple of what I think are broken springs - see pic with arrows indicating the springs. The top spring is attached to the weight (I think) but nothing else and the lower spring is attached to the screw but the other end is not attached. Does anyone know what these springs are attached to and are these parts available? Julian IMG_7994.JPG
 

KurtinSA

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I don't think your springs are broken...I have the same springs in more of less the same spot. The one that is arched seems to be used to put some pressure on the small cog that rides on the wheel in the center of the clock. You should be able to follow it down to that cog and see if it is pushing on the top of the cog. The other one that is straighter I'm not sure what its function is.

I doubt there's any availability...other than to buy a hulk from ebay.

Kurt
 

gspotjulian

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Not sure what to do now as it seems everything works but the clock does not. What I will add is if you manually operate the pin (See top arrow) from side to side, the weight moves down, the solenoid operates and the lever is clicked back to the top. When the pendulum is motivated and the pin is working from side to side under the pendulums own "steam", all the gears turn but the weight does not move down. - Any thought's? Julian IMG_7923.JPG
 

KurtinSA

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So you're saying that manual movement of the anchor pin at top, enough times, cause the weight to down and then eventually the solenoid engages and the lever is kicked to the top? If so, then it would seem that the clock doesn't have enough mechanical power...of a torsion clock type...to continue to run long enough for the weight to drop. There must be something wrong with the beat or fork. I mentioned early on that your fork is angled downward and the anchor pin is tilted...both of these are not right.

Kurt
 

gspotjulian

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Hi guys,
I'd like to thank everyone for the help and advice with this Kern clock. However, I have spent hours on it now and can not figure out what the fault is even with all the advice. I am going to pass it on to someone else who may be able to get it running. My guess it is something so simple that is evading me.
Cheers guys.
Julian
 

KurtinSA

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Are there no other people around you who have an interest in clocks? What about local shops where you could ask for people in the area for another set of eyes? I checked for a local NAWCC chapter in the UK and only come up with Chapter 103...no website but there's an email link to a John F. Taylor. Might be worth a shot.

Kurt
 

gspotjulian

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Are there no other people around you who have an interest in clocks? What about local shops where you could ask for people in the area for another set of eyes? I checked for a local NAWCC chapter in the UK and only come up with Chapter 103...no website but there's an email link to a John F. Taylor. Might be worth a shot.

Kurt
To be honest Kurt, if I was to take it for repair, the repair bill would out weigh the current market value so if I auction it I'm likely to get a better price because this is a simple fix which eludes me and from the description I have given it should let potential bidders know roughly what it is.
Thanks for all your help - Julian
 

KurtinSA

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I wasn't really thinking of taking in for repair. I thought you might be able to find a "kind soul" who had some skills in clocks and might be willing to look it over and help with conclusions.

Kurt
 

gspotjulian

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I wasn't really thinking of taking in for repair. I thought you might be able to find a "kind soul" who had some skills in clocks and might be willing to look it over and help with conclusions.

Kurt
I don't know anyone and this is the only website I could find where help is offered.
 

gspotjulian

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