I'm not sure what you mean by an arm pulling it back. And the switch does not push the spinner into place either.

The spinner should be designed so the majority of the weight is below the pivot point. So as long as it moves freely and nothing makes it bind it should never get stuck like that.

Usually this is caused by the switch resistance being too great. It could also be a dirty spinner mech or bent spinner linkage. Start with the easy stuff. Try removing the switch part and see if you can still reproduce it.

Spinner linkage is probably snapped inside the spinner itself. If so, you can fix it with music wire quite easily.

This is actually unlikely to be the case.

Try to lube the spinner wire where it rides on the metal supports. A very small amount of the teflon lube goes a long way.

Its been the case with my own, 9 year owned No Fear on two occasions with original spinners. The original wire goes all the way through the spinner body itself. To tell if its snapped, all you have to do is look at the spinner dead on and see if the end of the wires are in line with each other. If not, its snapped or about to. Not so sure that's the case here, just what i have experienced.

ebay.com link: NEW K S Small Diameter Music Wire Asst 20 520