This may be a Sony MP-F52W-50 drive. That drive is used in the 9114B and 9153 drive units. The pinout matches sort-of (in that a couple of pins you have tied high are in fact drive select signals, but it would be sensible to tie them high if not used). 6 DS3/ 10 DS0/ 12 DS1/ 14 DS2/ 16 Motor On/ I am a bit suprrised you didn't mention pin 10. This is DS0/, and could possibly be tied to ground in a single-drive system. The pinout is close to that of a PC drive. But a PC drive will _not_ work without major changes to the controller because the HP (or Sony) drive rotates at 600rpm -- twice as fast. If you have the old Sony drive, it's worth knowing that many of the parts (head, stepper motor, analog ASIC, motor driver chips, etc) are the same as in an Apple Mac 800K drive. Those are relatively common and make a good source of spares.