If it's one of the Tantalum-type "blasting caps" then there isn't
much of an issue, provided that the board isn't damaged. It's
probably a bypass cap, so the drive might even run without it, and
there is quite a range of things that will work just fine. Pull one
that's close (and meets the voltage ratings) off of one of your scrap
boards (don't worry, Tony - nothing too nice in mine, mostly PC stuff).