Abyss sometimes stops

[hottunaz]

My Abyss keeps excellent time but on the rare occasion I see it has stopped working.

When I smack the caseback with my palm, it continues to work.

When I shake the watch, I do hear the rotor quite loudly and maybe some other noises like something is loose.

I have opened it before, but I could not see any loose parts moving around. What could the problem be?

[hottunaz]

I also noticed when I regulated the watch, whenever I turned the regulating notch screw, the watch would stop and so I would have to tap it against my hand.

[krpster]

Could be any number of things. Almost impossible to diagnose without seeing it and testing. What is the movement? Key first piece of info.