[Coco] Coco3 System problem

[gene heskett]

On Saturday, August 27, 2011 05:07:28 PM john T Chasteen did opine:

> I finally had to take the 5.25 inch floppy drives out of their case.
> Drive
> Zero finally refused to read disk or format disk. I changed he option
> clips
> on drive one and optioned it to be drive zero. The failed floppy unit
> will
> still spin and the select light comes on but I cant format or read
> diskettes.
> Any suggestions will be appreciated in trying to "Fix" this floppy drive
> problem.
> I did use a "Cleaning Diskette"  to see if that would help.
> I am sure I can replace the floppy with one that is still good.
> Any suggestions will be appreciated.
> 
> John
> 
The amount of power for moving the head is miniscule in most floppies, and 
precisely moving the head depends on the lubrication and cleanliness of the 
rails or rods the head carriage slides on.  And in those drives that use a 
small stepper direct driving a long screw with spiral threads, and usually 
a small piece of piano wire riding in that spiral, the spiral needs to have 
all that 25 year old hardened grease cleaned out of its grooves and 
replaced with fresh grease.  I have used a dollop of std grease gun grease 
on several occasions, and had even had to remove the wire and turn it when 
it can be felt that there is wear enough that the 'threads are sloppy'.  
There is, on that type of drive mechanism, a bronze spring that rides the 
far side of the 'screw', and in the case of the amiga drives, has worn so 
badly that it wore plumb thru and then dug into the screw preventing the 
motor from backing up!

You will need a fresh box of q-tips, and/or an acid brush, and a can of 
acetone (obviously no smoking when the can is open) to clean out that old 
caked in grease.  Use the acid brush to poke at it and break it up, the the 
q-tip to remove it.  Do NOT put the dirty q-tip back in the acetone can, 
but grab a fresh one every time, they are cheaper by far than the acetone.

If that doesn't do it, along with a swipe or 4 across the heads face with 
the acetone to clean it, then something else has gone aglay.

Don't forget that one and only one floppy drive, the one on the far end of 
the cable, needs the terminator resistors installed.  Something I have been 
known to forget when I am shuffling drives around.  :)

Cheers, gene
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