Hello manicx :-)
It would not be a good idea to power a 3.5" Hard Drive from the motherboard floppy power connector as the printed circuit trace at these place are simply too thin to cope with the current the HD will request.
You can easilly burn these traces and damage your motherboard, sure this will take some time but it will arrives!
Amigalement,
Jean-François, Amiga ONLY since 1985.
