[Coco] CoCo floppy disk subsystem

[Arthur Flexser]

I seem to recall using my 26-3022 controller with a CoCo 2 without a
multipak.  The reason this worked was presumably that I had had to replace
the WD1793 controller chip some time previously, and the replacement sent
to me was a Fujitsu 8877, which I believe doesn't require 12V.

Can anyone confirm this about the Fujitsu chip?

Art

On Thu, Jan 14, 2021 at 1:30 PM John Mautz <ejmautz2 at gmail.com> wrote:

> According to cocopedia.com the 26-3022 is not compatible with the CoCo2 or
> 3 without using a Multi-Pack.
>
> http://www.cocopedia.com/wiki/index.php/26-3022
>
> The controller is based on the Western Digital WD1793. It features an
> analog data seperator circuit, infamous for its inherent unreliability and
> has multiple potentiometers which are used to calibrate various delay and
> timing features of the disk-side interface. It requires a +12 volt DC
> supply to operate, and is thus not compatible with a CoCo 2 or 3 unless a
> Multi-Pak Interface (or other source of +12V) is used or the CoCo or
> controller are "hacked", also contains the Disk BASIC ROM chip, and the
> necessary interface logic.
>
> Hope you have a multi-pack.
>
>
> On Thu, Jan 14, 2021 at 12:39 PM Salvador Garcia via Coco <
> coco at maltedmedia.com> wrote:
>
> > Happy New Year all. Thanks to Rietveld's exploration with using the GoTek
> > with a CoCo and other computers, I was motivated to get a GoTek myself to
> > test my floppy drive subsystem that is not working correctly.
> >
> > I have the 26-3022 floppy drive and controller. I had this working back
> in
> > the 80s with my CoCo 1. This past December I decided to unpack it all and
> > give it a run. Much to my dismay, the floppy drive subsystem did not work
> > as expected. I got as far as getting the formatting process started with
> > DSKINI 1, but after the head steps 34 times and seeks, I would get the
> > dreaded IO ERROR.
> >
> > Since I was on vacation in Mexico, I decided to bring back with me the
> > 26-3022 controller (the drive was too cumbersome and heavy).
> >
> > My plan is to swap out parts, specifically, the drive and cable, hoping
> > that the problem is with one of these. I have no way to swap out the cart
> > controller. I got the GoTek to substitute the floppy drive and I already
> > ordered and got a new 5.25" drive flat cable, with no twist.
> >
> > I received my GoTek yesterday and am in the process of installing the
> > FlashFloppy firmware. Here is what I have:
> >
> > 1. CoCo 2 and 3
> > 2. 26-3022 cart controller plus original flat cable
> > 3. New 34 pin flat cable for 5.25" floppy drives (this has one connector
> > at each end)
> > 4. 34-pin edge connector to IDC adapter (to connect the 5.25" drive cable
> > to the GoTek)
> > 5. GoTek emulator SFR1M44-U100K-R
> >
> > Am I able to build a working floppy disk subsystem using these items? Or
> > asked another way, is the 26-3022 compatible with the CoCo 2 or 3?
> >
> > Any tips or advice on building this system?
> >
> > As always thank you all for your time and assistance. Salvador
> >
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> >
>
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