So now that the SE/30 has been fitted with a replacement motherboard, it neither boots from a HDD (which in a former life booted, unless it has an OS which isn't supported -- I have no idea what's on it) or FDD. Upon insertion, the disk scans for a second, then promptly ejects.

It's a proper boot floppy, from 7.5NAD to a 7 boot disk to some F4.2/S6.0 disk. Nothing.

Cause? Shot FDD? PRAM battery is brand new.