Nowhere in the interfaces does the IBM unit have the same interface as the DEC RX01/02 unit. Well, maybe at the 120VAC plug :-). If you want to replace a DEC RX01/02 with something else, there were a bazillion RX01/RX02 clones made with their own Q-bus/ Unibus/Omnibus interfaces. Again, not the same as the serial bus between the bus interface and the DEC drives, but actually far more generic. Usually the clones use very standard Shugart 801 type interfaces somewhere along the way. Some have a Q-bus or Unibus card that has the 50-pin floppy bus on a header connector. Others have their own serial-type bus and a "formatter" card at the drive that turns that into the Shugart floppy bus. There were probably 20 different manufacturers of 8" floppy drives using the 50-pin Shugart bus. Maybe, just maybe, the head load pads in the IBM drive will work in a DEC RX02 :-). Tim.