Hi guys,
I've been imaging 1,000's of original disks from the 80's for my C64
project for years and this is very common. Some disks get what
appears to be a "clouded" film on them (perhaps mildew) that get on
the drive heads and is very hard to get off. The symptoms are as you
describe- once you try that disk all others will fail until you clean
the drive heads.
The scrubbing disks won't always clean them (I don't use these as they
can make the problems worse) but the drive is definitely not ruined.
You have to disassemble the drive and scrub the head(s) with alcohol
and cotton swabs and don't use that disk again. You can save the
disks if it's important by scrubbing the surface repeatedly with
alcohol and q-tips, but it won't last long after that- copy it
immediately and clean the drive again.
Some disks actually have some issue where the mylar coating will
actually come off when you try to read it. Same symptoms, but
different problem. When this happens you can look at the disk and see
where rings are scratched into it and the mylar will come off on your
finger. Usually I only see disks from certain software houses like
Synapse that have this mylar issue.
-
Pete Rittwage
C64 Preservation Project
http://c64preservation.com