Not sure if anyone can help me, but it’s worth a shot. I have a Pfaff 139. I have unstuck and oiled the entire machine, but the bobbin does not spin when the motor is engaged. The needle goes up and down, but the bobbin just sits there. I don’t see anything stuck in it. It looks like there is a single nylon (?) gear in the entire machine, and it appears to be part of the bobbin mechanism. It looks fine, but is it possible this gear is broken/stripped/cracked? Or am I missing some more obvious possibility?