What a great find! Very cool. I hope it works too. 👍
Found an old chess clock

Yes, I just let it run for an hour, and the time is accurate, even after a few decades of neglect. The USSR no longer exists, but their chess clocks still work.

It is rather easy to bleach the case to a whiter shade again, if you use a cleaner based on chlorine. I used a chlorine based cleaner that came as a gel and I applied it with a brush to the case. Keep in daylight (or even better sunlight) for some time and then wipe off the remaining cleaner with a wet cloth or wash it off with some water. After a few days at the latest, the yellowish colour will have disappeared - at least that was my result.
I did this with my "Marathon". Here is how it looked before and after.

It's the clockworks I'm thinking about. It costs hundreds of dollars to overhaul a good watch. You overhaul the movement to reduce the friction in the movement train. It should be done every seven to ten years. I have three good watches. I only maintain one at a time because I can't afford to maintain all three of them. So two of them don't get used. I also have a clock from the 1880s that I don't run. There's a clock on my mantel that I'm just running to death because it would actually cost more than it's worth to overhaul it. Although with that one I think they could just replace the movement and not have to overhaul it.
What a wonderful piece your clock is. I would say just put it on a shelf and display it. On the other hand, for what you paid for it, you could just run it to death. This is what it was originally built for. To be used then replaced. Problem is now they're becoming harder to replace. In the old days they would keep a small vile of kerosene in mantel clocks to keep the works lubricated.
The clock is accurate because it has a jewel for each of its four wheels and the parts in the movement are bigger than what you would find in a watch. That's why horologically, fine watches are called fine. Because they're accurate at a small scale. The second hand is located down by the six because that's where the wheel for the seconds is. It's actually more complicated to make a clock with the second hand in the center.


Jantar made xillions of these clocks and exported them to Western Europe and North America under the Marathon and Monroe names. I don't think many sold as Monroes because you rarely see them for sale. I purchased a Monroe in the late 1970s as my first clock. Can't recall how much I paid then but I bet it was under $35 Cdn. I recall how loud it was. A BHB was definitely a step up, quieter too.
Mine broke in the '90s, the internal plastic rocker lever. I disassembled it to fix, but ended up giving up on the project years later and threw it away. I don't miss it much. I use a 2010 most of the time now, although I still have an analog BHB and 4 Jergers. I've seen these old Jantars asking above $100 in recent times. Other than nostalgia, I'm not sure why. If I bought one today I would not pay more than $25 for it and probably never use it.
I was just moving some old belongings, and found a chess clock from my childhood: A 1970s Jantar chess clock, made in the USSR. It used to be white, but the plastic has turned yellow. Just out of curiosity I checked the value of this clock on-line, and it isn't much: $20-$50. I am not getting rid of it, but I will verify if it still keeps time well.
The cherry tomatoes are for scale.