[morzh]

yes that is the part I referred to, it looks like two arches connected together and then it goes to the lever connected to the shaft. The upper arch moves the wheel with slits to highlight the bands.
(I have this doc but was not able to really use it....I have poor spatial imagination ) I eventually used my own sketches I drew while disassembling.)

I wonder why it catches; mine didn't.

Anyways, be careful with that insulating tape wrapped around the bushing - it is a part of the audio switch, and should the insulation be broken, the switch will no longer work (that is it will silence the radio permanently).

Also there is that copper retaining leaf spring piece that goes in the groove there, also carefully sketch how it was before.

Then there is that spacing ring 13. This in fact might be your problem. Record which way it goes (it is not fully the same on either end but can go either way and I am not sure it should). It all pot metal I think, I wonder if this ring expanded or warped.