[Coco] CoCo 1 troubles

Arthur Flexser flexser at fiu.edu
Wed Dec 23 17:22:52 EST 2020


On some systems, especially those Tandy initially sold for the CoCo 1,
drive selection is done by having pulled pins on the different cable
connectors, rather than by jumpers within the drives.  If you look at the
cable connectors end-on, you should see different pins pulled on the
different connectors.  You should still have a terminating resistor in the
last drive in line.  Is there a prominent empty socket within the disk
drive that looks like a resistor might go there?

Do you mean DSKINI1, not DSKINI0?  Ordinarily, with just one drive, that
one would be Drive 0.  That DSKINI gets through 34 steps and then bombs
means that correct formatting did not take place, in that DSKINI has gone
back to Track 0 and begun its verify pass, trying without success to read
from the just-formatted tracks

Can you access files on an existing, already formatted disk with data on it?

Art





On Wed, Dec 23, 2020 at 2:59 PM Salvador Garcia via Coco <
coco at maltedmedia.com> wrote:

>  Thanks!
> I located a jumper labeled A/B MX. The jumper is on the center pin and B.
> Not sure if this is it. I can't find any reference to DSx
>
> OK, update: I connected the drive to the outmost cable connector and tried
> DIR 1 and got good activity on the drive. The LED came on :-D.
>
> I then tried DSKINI1 and the diskette started to format. I counted 34
> steps then the heads seem to have done a seek then another IO ERROR.
>
> This looks like a good step. Switching the cable connector made a
> difference. Thanks!
>
> Salvador
>
>
>     El miércoles, 23 de diciembre de 2020 12:10:12 p. m. CST, Arthur
> Flexser <flexser at fiu.edu> escribió:
>
>  There could be a problem with drive termination--a terminating resistor is
> supposed to be on the highest-numbered drive only.  Depending on the make
> of drive, this may be controlled by a jumper inside the drive.
> If you have only the one disk drive, you would want to turn on the DS0
> jumper and have DS1, DS2 and DS3 off.
>
> Art
>
>
>
>
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