[Coco] CoCo 1 troubles

[Gene Heskett]

On Thursday 24 December 2020 12:43:00 Salvador Garcia via Coco wrote:

>  Yes, totally agree. The only problem is that when I connect it to the
> cable's drive 0 connector, the LED does not light at all and the drive
> is not recognized. The motor spins up though, but that is all.
>
> Currently, I believe I have two problems:
>
> 1. Drive 0 is not recognized
> 2. Drive 1, while recognized, is still giving IO ERRORs
>
Its sounding as if that drive is not programmed to be drive one, which 
would make the twisted cable work, but as some other drive, selectable 
by jumpering the drive address wanted with a flea clip moved from ds0 to 
ds2. You'll find that on 5.25" drives but the 3.5"ers generally had a 
solder blob connecting the #1 PCB dots, look carefully.

But DS3 isn't available for OS9/Nitros9 because its miss-labled. its 
actually the side signal that OS9 uses to access double sided drives.

In that event replace any connectors on the drive cable that are missing 
teeth, with fully equipted connectors and do away with the twist. I 
usually just replaced the whole cable with new as it wasn't the best 
quality of cable to start with.

Then the drive will be same drive # regardless of where it is on the 
cable.

And remember that the resistor packs that plug into a 14 pin dip socket 
on the drive board, are only installed in the last drive on the far END 
of the cable.  It is not all that fast, but that cable IS in fact a 
transmission line that MUST be terminated at both ends.

> My next steps are:
>
> a. Try with a different floppy to see if that makes any difference
> while testing drive 1 

> b. Follow Bill P's advice and clean the heads 

> c. Swap cables. Barry Nelson provided information on how to make this
> cable, even providing references to the parts needed 

> d. Possibly test 
> the speed using the flourescent lamp method already suggested (I say
> possibly because I don't have a flourescent light here)
>
> Thank you for your continued help. It is much appreciated! Salvador
>
>
>
>
>
>     El miércoles, 23 de diciembre de 2020 07:08:52 p. m. CST, Arthur
> Flexser <flexser at fiu.edu> escribió:
>
>  If the drive is regarded as Drive 1 as you have it currently
> connected, it seems like it should be regarded as Drive 0 if you plug
> it into the other drive connector on the cable.
>
> Art
>
> On Wed, Dec 23, 2020 at 7:11 PM Salvador Garcia via Coco <
>
> coco at maltedmedia.com> wrote:
> >  Thanks again, much appreciated!
> >
> > I see the socket. It is populated. It looks like a white IC, stamped
> > "Beckman". Most certainly that's the resistor pack.

Yes.

> > Nope, DSKINI 1 it is. Trying to access drive 0 does nothing, only
> > the motors spin up then the IO ERROR.
> >
> > DSKINI 1 starts the formatting process and after stepping 34 times
> > and doing a seek, I get IO ERROR.
> >
> > Yes, looking straight into the drive connector I see some dark
> > areas. That's probably where the pins are missing.
> >
> > I can not access files on an already formatted diskette
> >
> > Salvador
> >
> >
> >
> >
> >    El miércoles, 23 de diciembre de 2020 04:29:14 p. m. CST, Arthur
> > Flexser <flexser at fiu.edu> escribió:
> >
> >  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
> >
> >
> >
> > --
> > Coco mailing list
> > Coco at maltedmedia.com
> > https://pairlist5.pair.net/mailman/listinfo/coco
>
> --
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Cheers, Gene Heskett
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