[Coco] ATX to CoCo3 conversion

[Frank Swygert]

Details for connecting an AT or other PS to a CoCo are in "Tandy's Little Wonder". The CoCo2 and 3 only need +5V and a little +12V and -12V for RS-232 operation. If you don't use the bit-banger you can get by with just a 5V PS in the 2 and 3 -- +/112V is needed for RS-232 traffic.

A CoCo with a pair of floppy drives (including the power the drives pull) only requires a total of about 30W, so can be run from the same PS. A newer model HD only pulls a few more watts -- a 60-65W PS would be all that's needed. I wouldn't use a PC type PS unless mounting the system in a PC type case. There are a number of surplus electronics places that have smallish (40-150W) power supplies that would work. Try Alltronics and Weirdstuff.

A mini-tower 80-150W PS would be suitable. Make a box for the PS and run wires to the drives and CoCo, or better make a box to hold the PS and drives then run power from that to the CoCo. A mini ITX case could be modified into a drive case and comes with a 80W or so PS. It's hard to find old drive enclosure cases! CD-ROM enclosures work, you may be able to find one for 2-4 CD-ROMs at a reasonable price that has a PS.


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Date: Tue, 25 Sep 2012 00:32:17 -0500
From: David Ladd<drencor at gamepixel.net>

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.