The mysterious Speedmaster hour counter

impaw · Jan 15, 2025

What a great thread, thank you @Archer !

I hope its ok to keep this thread alive with another issue? This one from my 145.022:

The hour counter resets perfectly as long as it has been counting for a long time, typically at least 6 hours.
If it has been counting for less time, lets say 1 hour, it will center a tiny bit to the right of 12.
...and again, if I let it run for 7 or 8 hours, it will reset perfectly on 12

The watch was serviced in June by a reputable watchmaker.
Did he miss something, or is this what to be expected by an 71 Speedmaster?
Than you again Archer💐

impaw · Jan 15, 2025

Here are pictures of the two typical reset points.
I have started and let the seconds sweep run a little bit after the reset, to give a clear sight of the locations the hour counter resets, BTW

Picture#1 is a reset after typically less than 10 minutes or more than 6 hours.
Picture#2 is a reset after 15 minutes to approximately 6 hours.

Archer · Jan 15, 2025

Certainly not expected. Keep in mind that when you press the reset pusher the hammer for the hour recording hand is directly controlled by how fast you press. If you press the pusher differently, you may get different results.

When you reset the chronograph, next time press and hold the pusher in, and note where the hand lines up, then release the pusher and see if it moves. That’s really the only other thing I can think of that might cause such inconsistent resets. In that case demagnetizing the watch might help, or the hammer/cam may have too much oil.

impaw · Jan 16, 2025

Thank you very much for your reply Archer!
I have done a couple of tests, and filmed the last test - holding the reset button, then releasing it.
No movement after the release.

I have not noted any difference yet, with different push-speeds but I will do some more tests today.

impaw · Jan 16, 2025

I have done some more testing during the day, and I get the same result regardless of the speed of the push.
i have talked to the watchmaker and he will take another look at it.
I will report back with his findings.
Thank you again!

Archer · Jan 16, 2025

The only time I can recall having an issue remotely similar to this, there was some damage to the face of the hour recording hammer, and a flat spot on the cam of the hour recording wheel. But it wasn’t exactly the same issue that you are seeing.

You might want to have your watchmaker look at those,

impaw · Jan 16, 2025

Archer
The only time I can recall having an issue remotely similar to this, there was some damage to the face of the hour recording hammer, and a flat spot on the cam of the hour recording wheel. But it wasn’t exactly the same issue that you are seeing.

You might want to have your watchmaker look at those,

Thank you Archer, I will pass along your notes 👍

zkramez · Jan 17, 2025

A lot of info to process in on this one! Good to know there are a lot of watch makers this thread.

impaw · Jan 27, 2025

impaw
Thank you Archer, I will pass along your notes 👍

I have now gotten the watch back from the watchmaker, and the issue has been resolved😀
I am (obviously) not a watchmaker myself , so I am not able to retell the exact cause of this issue.
But, as far as I understood there was (simply) a loose screw.
A screw that basically holds two components, and with this one being loose, the hour counter was imprecise, when reset.

I am sorry that I could not convey a better and more detailed explanation.
But the good news is that the watch now works!

Archer · Jan 27, 2025

impaw
I have now gotten the watch back from the watchmaker, and the issue has been resolved😀
I am (obviously) not a watchmaker myself , so I am not able to retell the exact cause of this issue.
But, as far as I understood there was (simply) a loose screw.
A screw that basically holds two components, and with this one being loose, the hour counter was imprecise, when reset.

I am sorry that I could not convey a better and more detailed explanation.
But the good news is that the watch now works!

That sounds like it has an older style hour rec ording wheel. This wheel was originally produced with a screw holding the cam to the wheel, so it was possible for that screw to come loose and fall out - I've seen that several times...screw missing here:

And assembled again:

Omega changed the design of this many years ago so that the cam is now riveted to the wheel, so this fault cannot happen:

Typically when this happens the screw falls out completely, and the hour recorder hand won't reset at all.

impaw · Jan 27, 2025

Archer
That sounds like it has an older style hour rec ording wheel. This wheel was originally produced with a screw holding the cam to the wheel, so it was possible for that screw to come loose and fall out - I've seen that several times...screw missing here:

And assembled again:

Omega changed the design of this many years ago so that the cam is now riveted to the wheel, so this fault cannot happen:

Typically when this happens the screw falls out completely, and the hour recorder hand won't reset at all.

This makes sense Archer, thank you.
I remember he said something about the "..old style..." of something, and he had now secured the screw with Loctite.

The mysterious Speedmaster hour counter

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