The USB (and SCSI, for that matter) Zip drives seem to be completely different beasts compared to both their internal counterparts, and their Jazz/Ditto siblings. The main board on those things simply has the external interface connector(s) and the internal mechanism connectors (i.e., custom ribbon cables for the R/W heads, spindle motor, etc); there are no 50-pin SCSI/40-pin IDE connectors in there.