It would be beyond my brief to think that I could help here without looking at it (and even then it is above my pay grade).
However, from memory the 1345 is uni-directional winding, clockwise.
This means that moving the rotor one way (anti-clockwise looking at the rotor) there should be no resistance and no winding.
Going the other way should encounter resistance, but it should not return to the start position, the fact that it returns would seem to insidcate that the tension generated by the winding is being lost returning the rotor, and is not being stored in the mainspring.
Edit - 18 holes of golf is hard work for a venerable old auto-chrono like this.....
If it's Lemania-powered, I'm interested. Tool Chrono - interested. Dive Chrono - interested. Interesting - interested