Omega 1310 quartz watch - date wheel not moving

peterg · February 23

I have an Omega quartz watch, which was a birthday present in 1977. It stopped working many years ago and I thought that it would be interesting to try to fix it. This is the first watch that I have tried to repair, and I am finding the experience both interesting and frustrating!

My watch uses the 1310 mechanism, and one of the issues that is baffling me is that the date indicator wheel (part 1310.9066) does not turn properly, seemingly because of friction (though the day indicator works fine).

On this watch, the date wheel can be moved on by either of two methods:

the hands passing through midnight, which also increments the day wheel or
when the user manually presses a button on the side of the case.

Method 1 (date change at midnight) involves a cog that engages with teeth on the inside edge of the date indicator wheel. This cog is turned via a magnetic coupling which consists of two metal plates that are shaped like a clover leaf (parts 1310.9062 and 1310.9064) - I have drawn a red circle around this coupling in the photo. When one plate is turned by the mechanism, the other naturally aligns itself magnetically, moving the date wheel. This magnetic coupling allows the date wheel to be turned independently when the user presses the button, without stressing the watch mechanism.

Method 2 (manual date advancing) uses a lever, circled in green, that engages with teeth that are moulded on the rear face of the date wheel. When the button is pressed, the date wheel is rotated just beyond halfway to the next date, and when it is released, the date wheel snaps fully to the next date because the magnetic coupling pulls it into alignment.

At least, that is how it is supposed to work. On my watch, the watch mechanism turns one of the magnetic plates, but the other does not follow, so the date wheel does not move. If I press the button to advance the date, the date wheel moves halfway (as expected) but it does not snap to the next date when I release the lever (because the magnetic coupling is not 'strong' enough to turn the date wheel). When I take the magnetic coupling out and separate the two plates, I can tell that they are still magnetically attracted, as they snap back into alignment, but I can't tell if the magnetic force has deteriorated somehow over the years, of course.

Assuming that the magnetic coupling is as strong as it is supposed to be, it feels like there is simply too much friction, preventing the date wheel from turning, but it is hard to know what might be causing this. There is no mention of any lubrication being needed for this step in the reassembly, so I presume that none is needed.

I haven't found any mention of this issue on the web, and I would be very grateful if anyone has ideas for things that I could try....

Thanks
Peter