Tipp on Felsa automatic movement not winding / stoppping

[Max]

Hi, I just wanted to place a tipp here. While I like the Felsa 4007N movement inside my Ulysse Nardin, I wanted to place a hughe tipp here.

My watch was sometimes working for days and then it seems to stop but on manual winding it was always working solid. Thus I suspected the auto winding mechanism, especially the bearing. It was not the case. 

After having disassembled this watch so many times and replacing the mainspring etc I finally found the fault. Its an driving Wheel which is transfering the power from the Autowinding to the ratchet wheel. The correct part number for my caliber was 1482.  The wheel consist out two wheels/gears which are just pushed into eachother. I guess this was done with a staking set initially.

So the fault lies in the detail that this smaller gear was becoming loose enough that sometimes the auto winding was not able to turn the ratchet wheel anymore. So in practical, this wheel was acting like a loose clutch. 

I missed this for quiet a while during any visual inspection but at a certain moment in time i tried to turn it with my tweezers and noticed the issue.

I was not able to fix it with my staking set as I am not experienced enough and just bent the Gear and the "closing" stump was not working as expected for me. Anyway.. I ordered the replacement and boom. Works.

So if you work on an automatic felsa with these symtoms, check that part.

Greetings

Max