3120 Power Reserve Issues

[SN2354]

Hi All

I have a 15300, with the famous 3120 movement. Had the watch only for about 6-8 months with little use. grey dealer claims it was serviced within a year at the time I bought it.

However I have not worn it much, so I when I wore it last week I simply set the time and wound it up a bit (30-40x) and it was fine. It died at some point, as I did not wear it all weekend so when I put it back on yesterday in the morning I simply set the time gave it only 5-6 winds and went to work.

Watch worked fine all day, but when I woke up in the morning the watch stopped at roughly 3am. This morning I set the time (without winding AT ALL as a test) at around 7:30 and going about my day and she is running just fine at the moment.

My assumption is the winding mechanism both manually winding and automatically working fine, but something is up with the power reserve if that makes any sense.

Does anybody have any experience with this issue, and a way I can remedy it? Obviously buying a 15 year old watch has its pros/cons, but if it was serviced roughly a year ago, it should not have PR issues like this. I know the typical response would be take it to AP, but I honestly am curious why this happens and maybe there is something I can do to remedy it before going off to AP for 4-6 weeks.

Any help is greatly appreciated!!