I've now tried a third drive, another Samsung SFD-321B. it also does not work. I'm sure this was working as I pulled it from a PC that was working last month. Now I have three drives modified (1 Panasonic, 2 Samsung) that don't work in my Amiga
. Later on I'll undo the modifications so I can test them in a PC.
I'll have to track down some more Panasonic drives because I have 4 Amigas and only two working drives, both are original and old.
EDIT: All four of the floppy disks I was testing with are bad, including my original WB1.3 disk. It appears that my modified Panasonic drive did the damage. Both Samsung drives work wonderfully! I used them to copy a working Zany Golf disk, and boot from it (original and copy). But when I tried to boot the copy from the Panasonic drive, it did not work, and that disk is now unreadable.
I'll take pictures of the modded Samsung drive and post them soon. They were easier to mod than the Panasonic drive (larger solder pads).