I seem to have a Problem with my rolleiflex fx: the camera doesn't properly stop at the first frame of a new film. It does stop, but only halfway down the film. I'm losing 6.5 frames! The problem is repeatable with Kodak film. The toothed wheel in the takeup chamber spins freely and seems to be tensioned. No visible indent on the backing paper.

Has anyone encountered similar problems? How many full turns does it usually take too advance to the first frame?