Here's another type of PC floppy drive modified for Amiga use - this time an ALPS DF354H (Revision 148F, but I don't think the revision matters - I've done this to a 121G too.)
Image attached, labelled as follows: (Feel free to cringe at my dodgy soldering!)
A: Use desoldering braid to remove solder from DS1 pads, bridge DS0 pads with solder. (Cause the drive to appear as unit 0, as expected by the Amiga.)
B: Cut trace leading from pin 2 of socket to chip. (Disconnect the redundant HD signal)
C: Cut trace leading from pin 34 of socket to chip pin 5. (This is the diskchange signal, which we re-route to pin 2 in step E.)
D: Solder a wire from pin 34 of the socket to pad marked "RD". (Makes the Disk Ready signal available to the Amiga)
E: Solder a wire from pin 2 of the socket to pin 5 of the chip. (Re-routing the diskchange signal.)
F: Solder a wire from the pad marked HD2 to the pad at the top left which happens to be a convenient ground. (Bypasses the HD detect switch so all disks are treated as DD - thus no need for tape over the HD holes.)
Hope someone finds that useful.