Bought a pre-owned 3700 world timer. Just got it back from a service in Switzerland via Swatch Toronto. The watch's minute hand loses 2 minutes a day. The seconds hand runs correctly (-1 second/day). After testing, I have identified the issue, the date ch...
My thoughts are that the date change is drawing too much power. In other words, your amplitude is dropping during the 2 or so hours it takes for the date to flip and that the drop in amplitude is hurting the timekeeping. Another possible issue - If you ha...