Inside a chess clock

A few months ago my son volunteered me to fix the broken chess clocks from his chess class. They are all analog and of different makes. I knew nothing about chess clocks nor how to fix them, but my son knows I like taking things apart. Sometimes I can even put them back together.

Amazingly I fixed 6 clocks. Or, approximately 6. I don’t really remember now. They were mostly simple solutions and none of them needed any parts. I don’t think any 2 had the same problem.

Inside analog chess clockThis last week the teacher sent home one more clock to be repaired. When I saw what the clock was doing, I knew exactly what was wrong because I hade experienced that problem with one of the previous clocks. I pulled it apart and was able to fix it in just a few minutes. I am starting to feel like an expert.

What makes a chess clock so special? Really they are just 2 (somewhat) normal clocks that have a system for starting one clock while stopping the other. The only thing that makes them different from a normal clock is they have a flag that drops when the time runs out. But, since they are analog, they continue to run.

One of the interesting rules of chess is that if you run out of time, you do not automatically lose. Your opponent has to claim the win because your time ran out. So if you arInside analog chess clock with clocks in placee able to put him in checkmate before he calls the win on time, you win.

In the first picture you can see the black bar is just a teeter-totter. When you push one button down, it stops that clock and starts the opponent’s clock. And vice versa.

In the second picture you can see where one arm is pushing down on the thingy in the clock that rotates back and forth. I am not a clock person, so I don’t know the technical name for the thingy, but it is probably something like “doo-ma-flatchet”.

Click the pictures for bigger versions.

14 thoughts on “Inside a chess clock”

  1. can you pls help me how to fix my bhb clock.. the problem is the 1st clock is running while the other is running but only 1 or 2 seconds.. pls teach me how to fix it pls.. i really need your help on how to solve this asap.. thank you

    1. I don’t really know what the problem might be Paul. Most of the problems I have found with the clocks have been obvious things. When I take it apart I see that a piece is bent the wrong way, or something has turned and causes the clock to stop, or not stop correctly.

      I can guess that maybe the arm that is supposed to stop the clock is not swinging out of the way when the button is pushed. This can be caused by the button on top slipping out of alignment with the arm inside the clock. Or the little metal piece of spring steel that stops the clock is bent.

  2. How did you get the clocks apart? My chess clock is obviously intended to come out the front when the knobs on the back and four screws are removed, but I can’t get the knobs which turn the hands to come off. Do they unscrew? Pull off?


    1. On all the ones I remember working on, the knob that adjusts the time just pulls off. The knobs for winding the clocks screw off in the opposite direction from winding.

      If that doesn’t work, let me know and I will see about getting a picture of your clock and trying to figure it out.

    1. Yes, dec, it is probably because the arm that turns one clock on and the other off is bent or broken. This is assuming it is an analog clock. If it is digital, then I am not sure what the problem might be.

  3. I have a BHB clock, actually hardly used. One winder went DEDOIOIOING and now will neither wind up nor unscrew. I can’t unscrew it backwards. Something seems to be going round and round inside it. I think I could get the other half of the back off but not the one where the problem is. I’m guessing a catch or a latch has gone and part of the mechanism is loose inside it. Suggestions??

    1. Michael, I am sorry, but I stopped working on these clocks 3.5 years ago because we moved out of that area. I am having trouble even remembering how to get the clocks open. I do remember that the BHB clocks seemed to be less repairable. They were harder to open. But that is about all I remember. I hope you get it figured out.

  4. I have a school chess club and several of the clocks are now missing some of the knobs – U he one that turns the clock hands and the winding knob. Would you know where to purchase replacements?

    1. I would first go to eBay or Amazon to get started. If you know the manufacturer of the clock, that would be easier to find the right parts. But I wouldn’t think that buying from the manufacturer would be very cost effective. They would probably charge as much for a knob as a whole clock costs. Stick to eBay and Amazon and see what kind of deals you can find.

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