Korg Mono/Poly

hi.
i am a new member of this group, my name is erik.

i was wondering if anyone knew where to find potentiometers for the 
knobs. i'm aware you can sometimes find parts on ebay or other 
classifieds. but can parts be used from other manufacturers? 

i also have a broken key i would like to fix. does anyone know what 
keys are compatable with the m/p, or where to find them?

thanks a bunch!
erik