I've just replaced a split loading motor drive bush on my Panasonic
NV-HD650 VCR (with K-mechanism). As far as I can see, there should be
no need to readjust the mechanism as I didn't disturb anything apart
from the motor, but on reassembly, there was a brief whirr of the
motor, then nothing. No fault codes and a when a video is pushed into
the slot, there is no attempt to pick it up.

I have decoded, I think, the phase diagram on the underside of the
case, and see that this refers to a tape in the loaded condition. My
problem is that I can hand wind the mechanism to the point where the
tape is in the lower position, but then it stops. At this point, the
metal pinion has reached the end of the rack and looks like it should
stop revolving when the main cam continues to turn. All looks OK so
far, but I cannot get the main cam to turn further and move the tape
loading arms. It looks like, if I could get it to wind a bit further,
that all the marks would be in alignment, so I am reluctant to start
dismantling further.

Does anyone know what might be stopping the mech at this point?

Thanks for any help