With some external drives, you can just open them up and plug in a new PC floppy drive.
I did this with an old Amitek External disk drive, just made sure the new drive had the 34 way connector on the correct side.
What made the task easy was a small PCB with a 16V8 PAL that dealt with the interfacing between Amiga and PC drive. I have made an image of this PAL but it will not transfer to newer PALs (and the 16V8 is near obsolete).
There are schematics that show how to interface a PC floppy to an Amiga, last one I tried would not boot all disks. Now I have a logic analyser, one day I may fix it.
Ian
