Floppy Disks and Bad Sectors

Is there any physical marks on the diskette media .. scoring etc.?

Have you given the drive heads a good cleaning?

Most common cause of floppy media failing is damage from a dirty drive, which is usually visible on
close visual inspection. Next most common cause is "old media" flaking away... this should still be
visible.

If you do see physical scoring or spots - check the drive heads closely. There may be
little bits of material stuck on them - which will score the media.

If you don't see visible damage, the disk may have been exposed to a magnetic field which would
corrupt the orientation of the magnetic domains which would make the data unreadable,
the disk would probably recover if re-FORMATed.

Might also have become desensitized, and need a good hit from a bulk eraser. (Write head not coercive enough to flip state, due to large homogenous domains)

An old VHS bulk tape eraser works great.

if the repair does not go according to plan, pull out the metal core from 3.5" floppy disks, you can make a tambourine out of them (yes, yes, like the one for a system administrator). a homemade tambourine can be a chic gift for experienced computer specialists

SD Card reader like this guy?
https://hackaday.com/2016/02/28/floppy-drive- … -sd-card-reader

DaveDDS wrote on 2025-03-24, 17:49:

Is there any physical marks on the diskette media .. scoring etc.?

Whenever I looked, the surface looked fine. I previously had problems with an Amiga chewing up disks and scoring was visible, but not with my own collection (yet).

Have you given the drive heads a good cleaning?

I have one of those head cleaning disks with the fabric disk, and I use some video head cleaning fluid with this (the fluid that came with the cleaning disk dried up long ago). Are there any other suggestions?

If you don't see visible damage, the disk may have been exposed to a magnetic field which would
corrupt the orientation of the magnetic domains which would make the data unreadable,
the disk would probably recover if re-FORMATed.

I think the disks I marked as "bad" were showing bad sectors after a format. I forget if I did these in my Windows 2000 laptop or my DOS 6.22 machine. I should check again, and try this NFORMAT program mentioned in the other thread.

i though a bunch of my floppys had had it, they would fail to format and a couple reported bad sectors in a similar area, turned out it was the floppy drive that had had it, i hadnt used it for a long time and it was packed with dust, so try a different drive just to be sure.

Quantum Fireball wrote on 2025-03-25, 20:12:

I have one of those head cleaning disks with the fabric disk, and I use some video head cleaning fluid with this (the fluid that came with the cleaning disk dried up long ago). Are there any other suggestions?

I would urge you to use a good amount of cleaning fluid .. the cleaning disk should be fairly moist
(not dripping wet, but not just slightly damp). If you feel you've used a bit much, let the drive dry
out a bit (after cleaning) - this stuff does evaporate.

I would also suggest using the "Clean heads" function of my own ImageDisk software
(available at "Daves Old Computers") - It will move the heads back and forth, essentially
"scrubbing" them on the cleaning media - much more effective than just sticking the
cleaner in and doing something that runs the drive (DOS will go to track 0 to read the
directory/FAT - which will fail, and stay there).

I also suggest trying a bulk eraser (if you don't have one, a good electromagnet driven by AC (transformer)
will do basically the same thing).

The idea is to scramble any magnetic domains which have become strongly aligned in some direction.

The important thing to do is activate the erase - move it over the disk side a few times, then
slowly pull it a fair distance away BEFORE TURNING IT OFF! - you want the AC field to grow weak, not just
"cut off".

You can get bulk erasers on ebay.

Like this recent listing.

https://www.ebay.com/itm/226515442305?_skw=vh … ABk9SR9Ddm_S5ZQ

I had good success with Dave's IMGDisk Erase Disk command. I repeat it a couple of times then go back to DOS and do FORMAT. Several cases got fixed with this method. Give it a try yourself.