[Coco] Mystery "FDC (EAGLE FORMAT)" Schematic on MaltedMedia FTP

[Chad H]

I gues with it being a deviation away from the standard controllers it would not be the best choice for trying to reproduce floppy controllers based around this chip.  I have been off and on investigating if such controllers could be reproduced for a reasonable cost.  I know I can get the WD1773 chips but they are a bit costly.  The MD8877A chips like was used in some of the FD-500 controllers is cheap.  I also found scans of what appears to be Tandy's own schematics for some controllers but they appear to be hand-written and somewhat difficult to make out.  Also, not every component is clearly identified.

I now have a total of 3 Floppy controllers, 2 FD-502s and 1 FD-500. I'm good with this for now but with them seemingly becoming more scarce and most of them with the non-gold contacts suffering from increased oxidation I thought it would be nice to reproduce some with the nice gold ENIG contact finish we have been seeing on some of these new projects.  We could even take the opportunity to upgrade the EPROM IC to support up to 27512's or maybe even something like the 256K EEPROM I'm working on that may be programmable from the CoCo itself. 

Of course, I have no idea how much interest there would be out there in this sort of thing as a lot of people seem to have abandoned floppies altogether.  If I invested the time and money trying to cobble up some prototypes it's very possible it may just be a one on one off deal.

- Chad

-----Original Message-----
From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of Darren A
Sent: Sunday, February 08, 2015 3:46 PM
To: CoCoList for Color Computer Enthusiasts
Subject: Re: [Coco] Mystery "FDC (EAGLE FORMAT)" Schematic on MaltedMedia FTP

On Sun, Feb 8, 2015 at 2:35 PM, Chad H <chadbh74 at hotmail.com> wrote:

>
> From comparing the board view, yep that's definitely the same board.  
> Was a version of Disk Basic ever made?  I'm guessing NitrOS9 
> compatibility is out of the question.
>


I did get a version of Disk Basic running on it.

Chuck was developing the NitrOS-9 driver himself and had reported some success. I don't know if he ever posted it anywhere, but if you found the schematic then I guess it could be out there.

- Darren

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