[Coco] CoCo floppy disk subsystem

[John Mautz]

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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