Removing Paillard P.F.R motor springs

[JimG]

I have a Sonora cabinet gramophone, I think an Etude, badged as made in New York but maybe assembled in Australia. The motor is a Swiss Paillard P.F.R. double spring, the spring nearest to the winder is disconnected somehow, the second spring seems OK to drive the spindle but can't be wound because of the issue with the first spring. I have read that this motor is designed to give easy access to the springs without dismantling the frame. I can get limited access by removing the winding cog but nothing further. There's a knurled knob at the other end of the shaft which looks like it might be unscrewable but at 100 plus years old I'm not game to get too heavy with it. Any advice welcome.