[Coco] [COCO] ATX to CoCo3 conversion

Brian Blake random.rodder at gmail.com
Tue Sep 25 08:09:47 EDT 2012

I did this with a (I think) 150w ATX ps from an HP computer to power 
everything (CoCo, MPI, floppy disks, VGA converter and fans) in my 
repack project - http://tandycoco.com/blog/ (which is now basically dead 
since I sold it last year when money got tight). I used this website: 
to rewire it for use as a 'lab power supply'. Then I used Frank's 
'Tandy's Little Wonder' book to figure out what modifications needed to 
be done to the CoCo and MPI and where to connect the required voltages 
to make them all work. The hardest part I had trouble finding was a 10 
watt resistor...

Good luck,


On 9/25/2012 1:32 AM, David Ladd wrote:
> I am not sure if anyone has tried to work out a circuit that would
> allow us to use a ATX power supply to power a CoCo3's motherboard and
> other devices in a PC case conversion.
> Back in the good old days I had gotten the document off of Delphi for
> the AT PS to CoCo3 conversion.  Though these days getting harder to
> find places that sell new AT PS.
> I know based on what I have seen the ATX PS provides a +5v line at all
> times for use in a circuit so that when you press the button on a
> normal desktop PC motherboard it then sends the +5v to the PowerOn
> line.
> What I would like to know is how safe it would be to just use a
> standard on/off switch with a pull up resister to send a on status to
> the PowerOn line on the ATX PS?
> --
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> Coco at maltedmedia.com
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