I didn't answer this before because I don't know about 1200 drives - are they DD or SD? The 500 drive is SD and is electrically compatible (if not mechanically), but it's only single density (880 kb discs).
If the 1200 is DD, the old 500 drive won't give you that functionality. You'll be able to use it for 880 kb discs, but not 1760s. On the other hand, if the 1200 drive is only SD, you should have no problems except mechanical ones.
tony
