[Coco] CoCo Model 1 Cartridge Port

[Arthur Flexser]

Sounds like a lubrication problem, perhaps.  Look for accumulated gunk in
the parts that move during stepping.  You can attempt drive operations like
formatting with the drive's cover removed, and perhaps get a better idea of
where the problem lies.

If the drive steps 35 times before the IO error, that means it has
completed the formatting pass , (or at least the stepping that accompanies
that stage) and is moving on to the verification pass, where the head goes
back to Track 0 and attempts to read each formatted (?) track in turn.  A
common pattern is that an IO error occurs right after the head has returned
to Track 0 and attempts to read the contents of Track 0.  This could mean
that nothing was actually written to the disk, or at least nothing readable.

Art

On Fri, Dec 24, 2021 at 9:48 AM Charles Hudson <charles484 at twc.com> wrote:

> Following your advice I moved the cable to the last connector (on the
> end with two connectors) and repeated the process of "dksini0".  This
> time the drive light came on and I could hear the stepper motor move the
> head.  I failed to count the steps - I was completely surprised - but a
> dozen steps or more activity ceased and the light went out.  The result
> on the screen once again stated IO ERROR.
>
> I then tried repeating the disk format.  This time I heard the mechanism
> straining; no regular repeated stepping and after a few steps with long
> pauses between them the activity ceased and I got another IO ERROR message.
>
>  From this I suspect that communication is good but maybe the drive
> mechanics or electronics are at fault.  It could be a tight sleeve, I
> guess, but I will eliminate that possibility after inspecting the drive
> mechanics.  I'll post back if I find something.
>
> Thanks for your suggestions.
>
> -CH-
>
> On 12/24/2021 8:13 AM, Arthur Flexser wrote:
> > Sounds to me like the problem may well be with drive selection, that is,
> > the drive or cable is not properly configured to make the drive behave as
> > Drive 0.  It is normal for the drive motors of all drives to come on when
> > any drive is selected, but the red light not coming on seems like a
> tipoff
> > that drive selection is the problem.
> >
> > Drive selection is accomplished in one of two ways.  If the cable is one
> > that originally came with the original (oldest) controller, model
> 26-3022,
> > it should have teeth pulled in the cable connector to accomplish drive
> > selection, by effectively disconnecting the select lines for the unwanted
> > drives.  Look at the end of the cable that plugs into the drive, head on,
> > and see if there are teeth that have been pulled.  Does the cable have
> > three connectors altogether, one at one end, which plugs into the
> > controller, and two more or less near the other end?  If so, try plugging
> > the drive into the opposite one that is near the other end, if you've got
> > pulled teeth in your cable.
> >
> > The other way drive selection may be accomplished is by jumpers inside
> the
> > drive.  If your drive has a DS0 jumper, you want to turn on that one and
> > turn off any other jumpers that are designated DS1 or DS2.  There should
> > also be a removable terminating resistor inside the drive.
> > The terminating resistor should only be plugged in for the drive that is
> > last in line, that is, farthest from the CoCo.
> >
> > Hope this helps!
> >
> > Art
> >
> > On Fri, Dec 24, 2021 at 6:40 AM Charles Hudson <charles484 at twc.com>
> wrote:
> >
> >> Yesterday I connected the controller to the CoCo and to the TCDD,
> >> following the procedure illustrated in the Tandy CCDS documentation.  In
> >> specific, the ribbon cable's red stripe toward the rear of the machine,
> >> using the non-keyed end of the cable, and the keyed middle connector to
> >> the drive.  I issued the command "dskini0" to format a disk and the
> >> motor turned, but no red light showed on the drive and after a few
> >> seconds a message indicating an I/O error appeared on the screen.
> >>
> >> Looking at the error message list in the documentation three remedies
> >> are listed: make sure the disk is inserted properly, try another disk (I
> >> did both) , and call the Radio Shack Repair Center.  Not sure how to
> >> accomplish that one.  But I will take the drive apart and see if there
> >> is anything obviously wrong.  It occurs to me, however, that the fault
> >> may be with the controller or the cable.
> >>
> >> Does anyone have experience with this issue?  I'd appreciate some
> guidance.
> >>
> >> Thanks,
> >>
> >> -CH-
> >>
> >> On 12/23/2021 3:15 PM, Arthur Flexser wrote:
> >>> No, Disk Basic 1.1 resides exclusively in the Disk Controller's ROM.
> You
> >>> must have Extended Basic to use any Disk Basic version, though.
> >>>
> >>> Art
> >>>
> >>> On Thu, Dec 23, 2021 at 8:40 AM Michael Miller <mvmiller12 at hotmail.com
> >
> >>> wrote:
> >>>
> >>>> I may be wrong here, but my understanding is that you need to update
> the
> >>>> ROMs in the actual computer to get DECB 1.1. The Disk Controller ROM
> >> just
> >>>> "expands" by adding a handful of commands.
> >>>>
> >>>> -----Original Message-----
> >>>> From: Coco <coco-bounces at maltedmedia.com> On Behalf Of Charles Hudson
> >>>> Sent: Thursday, December 23, 2021 7:12 AM
> >>>> To: coco at maltedmedia.com
> >>>> Subject: [Coco] CoCo Model 1 Cartridge Port
> >>>>
> >>>> On to the cartridge port, which seems workable.
> >>>>
> >>>> Verified that the Deluxe RS-232 Program Pak (Cat. 26-2226) can be
> >> invoked
> >>>> with "Exec &HC000"; I/O TBD.  Got modems and cables, need to find /
> >> create
> >>>> a driver.
> >>>>
> >>>> Also verified same for Disk Controller (Cat. 26-3022) which boots up
> >> with
> >>>> the message "Disk Extended Color Basic 1.0".  I have the disk cable, a
> >>>> drive and blank disks but no software.  End-to-end communication yet
> >>>> unproven.
> >>>>
> >>>> I think there are later ROM versions used with (some version of) the
> >> disk
> >>>> controller; can they be used in this cart?
> >>>>
> >>>> -CH-
> >>>>
> >>>>
> >>>> --
> >>>> Coco mailing list
> >>>> Coco at maltedmedia.com
> >>>> https://pairlist5.pair.net/mailman/listinfo/coco
> >>>>
> >>>> --
> >>>> Coco mailing list
> >>>> Coco at maltedmedia.com
> >>>> https://pairlist5.pair.net/mailman/listinfo/coco
> >>>>
> >> --
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> >>
>
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