[Coco] 24Pin to 28Pin EPROM Adapter PCB for sale

[Chad H]

Yea it was a pain trying to get it to fit correctly.  I had to trim the pins way down to the surface and almost flush the board against the FD-500 surface.  What FDC controller uses a different 24-pin wiring configuration?  I thought all of the ones that were 24 pin used the same configuration.  If this is true, then the design will work for all.

-----Original Message-----
From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of Mark Marlette
Sent: Saturday, February 07, 2015 2:09 PM
To: CoCoList for Color Computer Enthusiasts
Subject: Re: [Coco] 24Pin to 28Pin EPROM Adapter PCB for sale

Chad,
The reason my adapter board is a bit pricy($25) is because I used low profile machine individual sockets and pins. Each socket/pin is hand placed in a special fixture, this adapter is time consuming product to produce.
What is does give you is the ability to have the original lid on your floppy controller. There is no tolerance to allow for normal sockets and still have the lid go on.

The DOS Adapter's EPROM just touches the top and works in every FDC controller produced for the CoCo.

As the added wire fields work in you FD500 you will find that it will not work in other FDC applications.
Regards, Mark Marlette
http://www.cloud9tech.com
mark at cloud9tech.com

      From: Chad H <chadbh74 at hotmail.com>
 To: 'CoCoList for Color Computer Enthusiasts' <coco at maltedmedia.com> 
 Sent: Saturday, February 7, 2015 1:48 PM
 Subject: Re: [Coco] 24Pin to 28Pin EPROM Adapter PCB for sale
   
Self correction:
  * EPROM's supported: 2764, 27128, 27256, 27512

  * Controller Pictured:  FD-500 (26-3029)

-----Original Message-----
From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of Chad H
Sent: Saturday, February 07, 2015 1:44 PM
To: 'CoCoList for Color Computer Enthusiasts'
Subject: [Coco] 24Pin to 28Pin EPROM Adapter PCB for sale

With my recent acquisition and ongoing restoration attempt of a FD-500 controller, one of the things I wanted to do was get the 24-pin ROM out and put in an adapter for 28-PIN EPROMS (2764, 27128, 27256 & 25512).  I took a look around the web and at the Cloud-9 unit but honestly they were all a bit pricy for me and didn't give me easy access to the A13, A14 and A15 lines like I want because eventually I will be installing switches on the case to allow me to power down and switch ROM's quicker.

 

So. I designed my own PCB's and just tested one with the controller.  You can see pictures here .

http://tinyurl.com/m8992jh

 

The boards have header/wire access points for:  VCC, GND, A13, A14, A15 to make it easier to wire up switches.

 

The FD-502 controller pictured has a single green wire running from the A13 pin to the cartridge connector to allow the 16K rom to work properly and it has been very stable.  I will be adding switches for the A14 and A15 lines so I will be able to put 4 x 16K ROM's on a 27512 and have pretty much all my standard ROMs in one place, which I did on a EPROM adapter but not on floppy controller yet.

 

Anyways, I only really needed one of the PCB's so I have 2 extra if anyone is interested.


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