Back in the days when CDROM drives were very expensive and I had a brand new A3000: I used my old A500 with an A570 attached as CDROM 'server' via Parnet.
Late one night I had to print a page for the next morning, so I removed the Parnet cable, plugged in the printer cable and repowered the A3k - realizing that nothing happened and there was a smell of something burning in the air...
Of course I had plugged the printer to the SCSI port, situated very conveniently directly above the parallel port. Fortunately only two picofuses (pretty hard to get those days) and a vaporized board trace had to be replaced. And I added a blind DB25 plug to the SCSI port, just in case. ;-)