Hey Jules,
Try giving Matt Skaggs an email.
m.s.k.a.g.g.s@access-music.de (minus the .'s)
I broke two keys one time on my ti kb. And Matt sent me them. The XL rack has been out of production for a while, maybe they still have parts for it...
What's the issue? Are your pots crackling?
You can contact access and ask where the nearest repair facility is, message them and see if they can fix it.