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

14 Oct 2000

From: Claude &lt;claudew(a)sprint.ca&gt;

...
 These are the 1st floppy disks for the COCO made by RS.
The units are
TEC FB-201.

Large full size mounted on their side in silver case with power supply. 
...

When dskinit (format) command issued, they go about 35 tracks then an
error is reported on the COCO screen. 

You sure it isn't the first drives for the TRS-80?  The symptom would be
the older SA400 drives designed for 35 track operation used within.
The later drives were SA400Ls that  were designed for 40 track operation.
Both used the spiral groove cam but one was a bit different.

Open up the box and see which you have.

The other possibility is old (really old) media ment for the 35 track
drives and this media has a smaller "window" in the jacket that will
limit head travel.

...
 They can't read a disk formatted on a good drive.

That suggests teh head follower is out of the groove or
the stepper has been rotated or other wear probems.

...
 These drives use a plastic disc with a
"spiral" grove stuck to the
stepper motor shaft to step the head along. I have seen this in Apple II
drives, it seemed reliable...but I have been told these RS drives were
not really realiable... 

SA400 drives were very poor over time for reliability.  You would
need an alignment disk to set it up or lot of trial and error assuming
the head moves freely on it guide rails.

Allison