Double or High Density? As HD magnetic surface is too dense for use in SD/DD/QD drives reliably - it might be you are using the wrong type of disks in your drives?
A good giveaway that a disk is DD is they usually have a hub ring. Hub rings were necessary on DD disks because some drives (Apple II?) couldn't grip disk without one.
Thx for the reply. DD. Definitely using DS/DD with hub rings. My zorba seems to spin them fine. I bought a still shrink wrapped box of dshd 3Ms (out of curiosity) and I managed to format roughly 30 of the tracks.
A good giveaway that a disk is DD is they usually have a hub ring. Hub rings were necessary on DD disks because some drives (Apple II?) couldn't grip disk without one.