5.25 floppies that read but don't write

Chuck Guzis cclist at sydex.com
Thu Aug 20 23:46:41 CDT 2015

Re:  Degaussing floppies.

Only part of degaussing a floppy is getting a strong enough degausser--I 
use on made for wiping VHS carts--it gets very hot after only about 3 
minutes of use and the thermal cutout belays my impatience until it 
cools off.  So it's definitely not wimpy.

However, to use it, you have to observe the correct mumbo-jumbo.  You 
press it against the floppy in question, hit and hold the power button 
and *slowly* pull the disk away, moving said disk in a roughly circular 

A quick check using Kyread shows no discernible magnetic pattern remaining.

On a related matter, I've found that using a very strong rare 
earth/neodymium magnet (i.e. if you get your fingers between it and a 
hunk of iron, you should not be surprised with broken bones or severe 
tissue damage)  on a "bad" high-density 3.5" floppy, followed by a pass 
with the degausser will often return the floppy to usability.  This 
comes up occasionally when I'm asked to repair a factory-labeled floppy 
that's developed issues.  You want to keep the original labeling and 
short of inserting a new "cookie", this approach actually works.

For what it's worth, I use the magnets with large steel ball bearings to 
roll dents out of sheet brass--so I do have a valid reason for having 
one around.

This goes to an observation that DSHD 3.5" media appears to develop some 
sort of "fatigue" after a certain number of write passes.

For what little it's worth,

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