My shooting club has motorized target carriers on the indoor range. They
use "Maxtorq" gear motors, and one isn't working. The motor shaft spins,
but the output shaft doesn't. It doesn't make any excess noise like
grinding of gears or anything. These have been in place since at least
1970, and they have been so realible that I don't know if anyone is around
who knows much about them.

I suspect either a set screw or Woodruff key has let go in the gearbox, but
it's also possible that a shaft has snapped or a gear hub has busted loose.
I've never worked on one of these things & was wondering if I should
concentrate on finding a spare (we may have some someplace), or try to
repair it. If it's likely to be a quick fix, I can leave it wired up &
work on the gearbox end. Otherwise I'll have to completely dismount it.
The winter pistol league has just started, and we need every firing point
we have.

Thanks!