hp 9153 floppy & disk

Actually, having re-read the HP CE manuals on hpmuseum.net, I think I was mistaken. All 9153s and 9154s used the Nighthawk drive. It's the one part that's common to them (the PSU, controller board and floppy drive did change). I have a later one, a 9154B. The controller board in that has a large ASIC that cotnains the floppy and hard disk cotnrollers, etc. The -A models have larger controller board stuffed with chips, inclduing a couple of Adaptec chips for the hard disk controller. The Nighthawk is a curious drive. It uses a stepper motor for positioning, but it microsteps it (there's a dual DAC on one of the drive PCBs with an ADC for postion feedback). The interface is raw data to/from the reaad/write chain (clock separation, ID location, etc is done on the controller board, not the drive) but with an 8 bit data bus and strobes to read th ADC, write to the DAC, etc. I haev some detials, but not enough to make a replacement drive. The Nighthawk was used in some models of Vectra from what I've read. I beleive you could reformat a Vectra drive to use in a 9153/4 but not the reverse. -tony