[old_tv_nut]

If you look at the 3rd pic, you can see the tuner-end pulley. It has a wide slot (hidden behind the shaft) that the string enters after wrapping around at least a half turn, and then the string has a loop that hooks onto a tab. Both ends of the string have the same sort of loop, but you can see I managed to pull one loop open. There's no evidence of a tensioning spring I can see, but adding a small one might be a good idea.

So, the string path is:
End loop on tuner pulley, small pulley, knob pulley (multiple friction wraps), second small pulley, second end loop on tuner pulley.