I'd make sure the drive heads are very clean, and try other drives (also very clean) if you can.
You can use my ImageDisk to see what sectors you can read, and to make a backup even with sector errors
in some places.
(ImageDisk also has "clean heads" function where (with some cleaning solution - or at least some alcohol - it
will "scrub" the heads back-and-forth, much more effective that "doing dir to make it spin.")
ImageDisk has to run under pure DOS because it access the floppy controller
directly and in traditionally non-standard ways. (ImageDisks primary purpose
is to archive/restore "vintage computer" media - that means ANY format the
the PC FDC can physically read/write - not just DOS/MicroSoft formats - I
even use it for old 8"s systems - I give information of making an adapter on
my site).
For this reason, ImageDIsk does not "go through BIOS" or make use of BIOS
floppy-drive configuration (my ImageDisk systems does not even have the floppy
configured in BIOS).
Best place to get it is: "Daves Old Computers" -> "Download Software/Images"
(near the bottom).
Dave ::: https://dunfield.themindfactory.com ::: "Daves Old Computers"->Personal
- Dave ; https://dunfield.themindfactory.com ; "Daves Old Computers" ; SW dev addict best known:
ImageDisk: rd/wr ANY floppy PChardware can ; Micro-C: compiler for DOS+ManySmallCPU ; DDLINK: simple/small FileTrans(w/o netSW)via Lan/Lpt/Serial