Well, I've ordered TOS 1.04 in a 6 chip set.... The floppies are mostly pirate copies of games and they're all on Sony Brand Micro Floppydisk Single Sided MFD-1DD disks, so I'm sure it's the disks and not the drive,
I've also got an SF314 I bought for $3.... it said "bad" on the price tag. I couldn't get it to take a floppy on insertion. Tonight, I opened it up and found something that looked like it had gotten caked up so I cleaned old lube out with ronsonol and re-lubed it with white lithium grease. Then I put a disk in and it didn't like the disk when I tried to format it, so I had it "format" a cleaning disk instead.... It was then able to format a double sided floppy, but then it started reporting that the disk wasn't responding when I tried to view it on the desktop... but after retrying and rebooting a few times and making it try to access repeatedly it seems to be working every time. It's very noisy... I wonder if it will still work when I come back to it in the morning.
Oh... check out that yellow SF314. ooh... and the lovely crooked picture on the SC1224.