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1970's? vintage German Urgos Electromechanical Mantel Clock won't run
Hello everyone, today at work (Goodwill) I bought a ca. 1970s vintage German Urgos Electromechanical Mantel Clock that takes a 1.5 volt "C" Battery to run the clock, and anyways the clock says on the movement (in German and in English, seeing as it was an export piece) that when you install the battery you need to start the clock by turning it about the oscillator axis (which in this case I believe they mean the balance wheel when they say the "oscillator") and when I would do that the clock will run for a few seconds and then it will quit, so I don't know what the deal is with it, and knowing that basically all the clock is is just a bunch of plastic and metal gears driven by a balance wheel (the "mechanical" part of the electromechanical movement) and the balance wheel is driven by a small electrical circuit that powers a small horseshoe type magnet that in turn drives the balance wheel (the "electro" part of the electromechanical movement), and anyways its acting like its either not getting enough juice to keep the balance wheel oscillating or the balance wheel is wonky (its out of alignment) and either way it seems I may need to take the movement apart to diagnose the issue but I already had to take the clock apart today to repair the dial because the original glue they used to attach the dial to the brass backing material had dried out and failed and was crumbling all over the place so I had to clean out the old glue and reglue the dial back onto the backing material using Elmer's Multi-Purpose Glue.
Anyways I would love to get this clock up and running again as its kind of an unusual piece and also its kind of a piece of history seeing as this clock was made when there was still an East and West Germany (although the clock itself just says "Made in Germany" it is assumed that it was made in West Germany like it was with the old German radios like the old Grundigs and Sabas And Telefunkens were.) Anyways would like to know if anyone has any experience with these old German clocks or more specifically these old German electromechanical movements. Thanks, Levi P.S. Pictures are posted below of the aforementioned clock and also this clock is made of solid brass. Edit: I said this clock was from the 1970s, well I was mistaken its actually from 1960, and to be exact its from March 2, 1960 according to a stamp that was stanped onto the front of the movement. I have a picture of the inside of the movement, and to be honest its probably one of the simplest looking electromechanical movement designs I've seen so far, as the only electronic component inside this movement (besides the electromagnet that controls the balance wheel) is a small diode, which when I tested it with the diode test it tested bad because it was allowing current to flow both ways instead of just one way, which I'm not sure if that's why the movement isn't working or not but I'm probably guessing it is seeing as there isn't anything else in this movement that could of failed to cause the mechanism to not function, and considering that the battery terminals in this clock mechanism are absolutely corrosion free it only makes me suspect the diode even more as being the culprit. Last edited by Captainclock; 01-28-2017 at 09:33 PM. Reason: forgot to add pictures. |
#2
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Unsolder one end of the diode and check it. You could be reading through another part. If it still reads shorted, then replace it. It looks like a Germanium diode, that might be the only kind available at the time. A 1N4148 should replace it.
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#3
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So with that in mind I'm pretty sure the diode readings I was getting were accurate. Which means that the diode is either a.) bad or b.) there is someting else wrong with the clock mechanism that's causing it to not work. |
#4
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According to the spec sheet, this is a germanium signal diode, not a Schottky diode.
The use of a germanium diode rather than silicon may be important in that the power supply is a single 1.5 volt cell, and the germanium diode will reduce that by about 0.3 volts rather than the 0.7 volts of a silicon diode. Replacement would be a 1N60. http://www.semicon-data.com/diode/dc/AA116.html |
#5
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I have an alarm clock similar to this, single D cell battery, driving a mechanical movement with a coil to keep the balance wheel going. Bought it at goodwill, it was ticking away with a battery in it. Ran for over 2 years with that battery. I replaced it and its been running for 3+ years on a fresh Alkaline.
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Audiokarma |
#6
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its possible your issue is mechanical, from old gummy lubricants putting more load on the mechanism than it can handle.
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I would definitely unsolder one end of the diode to test it, as it might be wired across the coil, which would be fairly low resistance. jr |
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I did a Google search for Urgos clock parts, and found at least one company in Virginia that stocks them. The problem is the parts are extremely expensive; the lowest-priced movements, for example, are just under $600, while the fancy ones that chime every 15 minutes are priced well over $1000.
I would try to restore the original movement if at all possible. The germanium diode mentioned in VK member Captainclock's post is probably shorted if his clock doesn't run. This could well have been caused by the former owner accidentally installing the battery backwards, which of course will destroy the diode in no time flat. That the diode allows current flow in both directions, rather than one, would indicate the component is in fact defective and, of course, must be replaced before the clock will operate at all.
__________________
Jeff, WB8NHV Collecting, restoring and enjoying vintage Zenith radios since 2002 Zenith. Gone, but not forgotten. |
Audiokarma |
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And yes I was thinking that I would need to replace the old diode with a new one but it seems that there are 2 different replacement diodes mentioned on here for my clock's diode and I'm not sure which one I need, the original diode was an AA116 Germanium diode which I would like to know if there's a modern replacement for that diode or if there's anyone on here that would happen to have a NOS AA116 Germanium diode I could buy off of them or know where I could get some NOS AA116 Germanium diodes. |
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Well, I took the cathode side of the diode (the side with the line on it) out of the circuit on the clock (the side where the diode is connected to one side of the coil for the balance wheel of the movement) and remeasured the diode and sure enough the diode is definitely shot because using the diode mode of my DMM it shows O.L. in both directions. Which means that yes I will definitely need to get a replacement diode for this clock mechanism, which it seems that after some browsing through eBay there were several listings for NOS AA116 Germanium Diodes for sale on eBay being sold in packs of 10, 20 and even 50 for about $10 and free shipping, they even had NOS 1N60 Germanium Diodes for sale on there.
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#13
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Hi, one thought. I worked on DC clocks (actually car clocks) in the 60's. They were basically mechanical spring wound clocks. This was before miniature electronics. They had an electric contact that closed when the spring ran down. This momentarily powered a solenoid that kicked the spring and wound it. 99% of the time, the problem was dirty or welded contacts. The diode is across the solenoid coil to clamp the back emf voltage when the contacts open. The diode can blow (open or short) if the battery was put in backwards.
If this is the type of mechanism you have, you should be able to wind the spring by hand to see if the mechanism works. If so check the contacts. Hope this helps. |
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I'm thinking that it might be nothing more than a simple electro-mechanical "relaxation oscillator" consisting of an oversize balance wheel with attached permanent magnet that is put into motion by an electromagnet that is triggered by a set of switch contacts that are momentarily closed perhaps by a post on the wheel. The diode likely is used to damp the coil ringing when the switch contact is broken. A few plastic gears then advance the hands when kicked by the balance wheel motion.
Just a WAG, jr |
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Audiokarma |
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