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  #1  
Old 01-28-2017, 08:33 PM
Captainclock Captainclock is offline
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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.
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Last edited by Captainclock; 01-28-2017 at 09:33 PM. Reason: forgot to add pictures.
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Old 01-29-2017, 10:08 AM
dieseljeep dieseljeep is offline
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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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Old 01-29-2017, 09:16 PM
Captainclock Captainclock is offline
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Quote:
Originally Posted by dieseljeep View Post
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.
It is a Germanium diode, an AA116 to be exact also known as a Schotsky diode which is a 75 hz rectifier diode that is for use in RF circuits according to what I've read about it online. The funny part is that the Germanium diode is the only electronic component inside this clock mechanism so there isn't any other parts for the diode to interact with to cause a false reading, the only other "electronic" part in this movement is the electromagnet that's used to keep the balance wheel oscillating but that's technically not an electronic part as its not a transistor, resistor or a capacitor, its more like an electrical device.
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.
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Old 01-29-2017, 09:38 PM
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old_tv_nut old_tv_nut is offline
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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
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Old 01-30-2017, 04:18 PM
Olorin67 Olorin67 is offline
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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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Old 01-30-2017, 04:18 PM
Olorin67 Olorin67 is offline
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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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Old 01-30-2017, 06:56 PM
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Quote:
Originally Posted by old_tv_nut View Post
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
I agree with your conclusion, but there is cause for the confusion... AA116 also refers to a SCR and a Schottky diode as well... odd that the number has been used for several different devices over the years.
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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Old 01-31-2017, 06:13 PM
Captainclock Captainclock is offline
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Quote:
Originally Posted by jr_tech View Post
I agree with your conclusion, but there is cause for the confusion... AA116 also refers to a SCR and a Schottky diode as well... odd that the number has been used for several different devices over the years.
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
Yes, I it is wired to one side of the coil, so should I clip the lead that's attached to the coil and then test from there? Also I agree it might be possibly a mechanical issue as well (gummy lubricant) but the only problem is that I have 2 other clocks with a similar movement in them (one a Seth Thomas and one a Japanese made unit) that both worked just fine by putting a new battery in them (but had to adjust the clock speed as the clocks were running either too fast or too slow as they were) plus with the majority of the gears in the movement being plastic I would think they wouldn't need to have any lubricant in the movement seeing as its not a metal to metal contact like in a traditional mechanical clock.
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Old 01-31-2017, 06:17 PM
Captainclock Captainclock is offline
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Quote:
Originally Posted by Olorin67 View Post
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.
I think I have an alarm clock similar to yours that I also bought from Goodwill but the movement was trashed inside it (the balance wheel was out of its pivot, and some other issues I can't remember right now) anyways it was missing its handle ontop of the case and some of the feet on the bottom were missing as well, so its just kind of a parts unit for right now.
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Old 02-01-2017, 03:30 AM
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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.
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Old 02-01-2017, 07:17 PM
Captainclock Captainclock is offline
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Originally Posted by Jeffhs View Post
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.
Wow! That's crazy that those clock movement parts are that expensive!
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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Old 02-05-2017, 06:29 PM
Captainclock Captainclock is offline
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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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Old 02-07-2017, 07:17 AM
ron07663 ron07663 is offline
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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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Old 02-07-2017, 05:36 PM
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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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Old 02-08-2017, 10:02 PM
Captainclock Captainclock is offline
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Originally Posted by jr_tech View Post
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
Yes, indeed that is the case with this one, although I do know what kind of movement the guy before you was referring to because I actually did have an old electromechanical clock from the 1960s that was of the flip-dial persuasion that had an electromechanical movement in it that was actually a fully mechanical movement that was wound up by a solenoid that kicked a motor on that wound a "mainspring" up in the movement and then the clock would run for about a day until the spring wound down and then engaged the solenoid that engaged the motor that wound the spring up again but that clock had too many issues for me to fix and I ended up junking it. but yes I believe this clock I'm working on right now does indeed have a fried diode and it was more than likely fried due to a battery being inserted wrong at one point in time in its life.
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