I haven't seen the guts of a USB Zip, but the SCSI internal is a different machanism than the external unit. A conversion didn't look possible to me, so I traded a guy an external(I have 3 or 4) for an internal to stick in the floppy spot of my old 8500. Works fine now, had to widen the slot in the bezel about an eighth inch each side to accomodate the Zip disk.