Does the machine wind the old bobbins? The one that came with the machine? If it doesn't wind at all, besides a new clunker bobbin being the problem, don't forget to oil the little hole in the winder, don't forget to look at the rubber bobbin winder wheel and see if it is worn or too slick, is it making good contact with the handwheel? Is the clutch on the handwheel disengaging? It probably is just the bobbin itself, but these are other things that can affect it. I have 4- 301s and they are pretty much trouble free, just excellent machines. The one I just got has a problem when winding the bobbin- the needle bar keeps moving even when the handwheel silver knob is disengaged, so I have to take the handwheel off and clean- however I need an expanding pliers to get the ring off and have to buy one.
Keep at it- the machine is worth it.
Linda