Need help or service manual for RS COCO mini disk 26-3022... - test-drb@ccmp.vtda.org

15 Oct 2000

From: Joe &lt;rigdonj(a)intellistar.net&gt;

...
 >Coco were Shugart SA400s.  That is a 35 track drive
with the spiral groove
...
 >disk.  Allison pointed out that there was a later
model (SA400L) that
>could handle 40 track.  BTW, if you have decent machine shop capabilities,
...
  the SA400 could
easily be modified for more tracks, but it is NOT a
handheld Dremel task. 

   How many tracks can they be made to handle? Any details about how you go
...
 about changing them? 

The number is 40 and it's at 48tpi.  Te trick before the SA400L (40 tr)
version
was around was to mill the groove further and mill the end stop.  Both
were
done at high precision.  Or sub in the disk from the sa400L.

It was done back in the days when 35 tr was passe` and 40 tracks were
emerging as the standard for 5.25 floppies.  It was a big deal then as
with
single density that meant another 12.5k on an 90k disk.  If you had DD
controller so much the better.

Other common mods were to go to SA450s (40 cylinders two sides) or
other far better drives.

Allison