Thanks Jason,
Yes that's my camera. S2
So with no DE switch I guess that's not the problem. Actually I need to correct my description of the symptoms.
It actually doesn't wind on to number 1 position. It goes about 30% of the way from 0 to 1 then doesn't want to carry on winding the film. Also at this point the, manual film advancing mechanism that's supposed to be used for spooling the film on at the end of the roll becomes jammed and I cannot rotate it at all. It's as if something is becoming jammed In the backs winding mech but disconnecting from the body as the shutter is still charging and releasing.
Anybody got any ideas?