I am using a 40mm diver watch with a Seiko NH35 Movement, and I’ve had it for a few days. I once left it at night after winding it up fully, and came back in the morning to find the balance stopped, with the time showing a few hours after I left it. I wound it back up, and had to give it a shake to set it moving again. After that, I was able to leave it for 8 hours, but it’s already 7 minutes behind. What should I do?
Are you able to de-magnetize the movement?
I haven’t done anything to magnetize it, so unless it came magnetized, I shouldn’t have to, right?
Wristwatches can easily become magnetized by a number of outside influences. Usually a magnetized movement will run fast, but it isn’t always predictable. Losing 7 minutes in 8 hours is pretty extreme, demagnetizing is easy and quick, so I thought it would be worth looking into.
It could have lost a bunch of time just because it stopped moving, but I don’t know for sure. When I came back, it was still running, so I think that’s probably not what caused it. I also don’t have a demagnetizer on hand, so I can’t test out your idea. I tried putting a compass near the watch, and the compass seemed to follow or be pushed away from the watch, but I don’t know if a watch normally has some magnetic parts or whatever.
I wound it up fully and left it running overnight. After 17 hours, I came back and checked on it to see that it had stopped, showing that almost 15 hours had passed according to it.