Greaseweazle

On 2/3/21 5:59 PM, Fred Cisin via cctalk wrote: I didn't ever send him an F85 diskette, just a sampling file from a Catweasel. One thing about those 5.25" 100 tpi diskettes is that data is clocked at about 350 KHz, as opposed to 250 KHz for a standard drive. The upshot is that even you find a 100 tpi drive, the drive electronics probably will require a bit of "tweaking" to give a bit more headroom in the bandpass. When I tried a stock MPI 52 100 tpi model, I had to modify it slightly to get it to work reliably; same for a Tandon TM-100-4M. I think Micropolis drives worked without modification, but the ones I have are single-sided and so haven't been used in some time. One of the things that I meant to get around to doing, but never did, was to take one of my Drivetech 5.25" drives and add my own PCB to do the micropositioning. (Those drives have two positioning steppers on a sort of lever arrangement--one for coarse and the other for fine). Nominally, the drives are 192 tpi and use an embedded servo for the high-capacity capability (which is why the drive couldn't format its own high-capacity floppies). --Chuck