Since schellbl shared, thought I would too. We had one system whose floppy just wouldn't work. We tried different boards, cables, drives, floppies, etc with no luck. Finally we thought to take the drive out of the cage (just set it somewhere for testing but keep it connected) and it booted to a floppy with not prob. It must have been some sort of odd short with the drive and the case.
Though unlikely to be you prob, ya just never know!
Though unlikely to be you prob, ya just never know!