On Wed, May 1, 2024 at 5:38 AM Paul Berger via cctalk <cctalk@classiccmp.org> wrote: > > As Mike said there are two models 9114A and 9114B, they are functionally > equivalent, however the B model uses a 1/2 high drive mechanism and I > believe there are changes to the controller as well, but I have only > seen the inside of a B model.
I've got both types and not surprisingly have been inside them. The controllers are similar in design -- the main changes are for the different drive type and the better battery status monitor on the 'B' -- but are not interchangeable. You probably could get it to work, but.. The -A uses the original Sony 3.5" double-head drive. This always runs at 600rpm, the HP one is not modified. The -B uses a later drive, also 600rpm, which shares a lot of parts with the Apple 800K drive (head carriage, stepper motor, analogue IC...) should you need to do repairs. The older drive has a 26 pin data cable and separate 4 pin power cable, the later drive has a 34 pin cable for data and power (power is on some of the odd-numbered pin, they are not all grounds as you might expect). The disk-inserted sensor on the -A is a spring-loaded plastic part which interrupts the beam of a slotted optoswitch on the motor PCB when a disk is present. Amazingly it lines up with the 'high desity hole' in 1.4M disks. So unless you rigidly block that hole it is likely the drive will not detect such a disk. As others have said the 1.4M disks are higher coercivity so using them is unreliable at best. -tony
