Handwind cal eb8021 randomly stopping when not in use

[schtozo]

Hi, im having this issue all of a sudden with this new vintage i aquired. It has an eb8021 movement. First 3 days i wore it and it kept running good till next day overnight when not in use. Next morning i could wind it around 15 turns. The fourth morning i went to use it and noticed it had stopped. It was 7 hours behind, so i figured it stopped around 2 hours after taking it off. But to my surprise it started ticking again the moment i picked it up. That morning i could only wind around 7 turns. Next morning it did the same and i only could wind it 7 turns as well. So i used it and it didnt stop never during the whole day.... 

my question, what is happening to the movement overnight when not in use? Is it stopping because it needs service? Why is it not stopping when in use? Why is it that it didnt stop the first 3 overnights when resting?

thank you in advance...

[rogart63]

The EB8021 is a pin lever movement. Think you movement needs a service. It's common that watches work a few days after someone starts to wear it more often. The old oil and grease is hard and brittle. If you would put the watch in a machine you would notice that it has a very low amplitud.