The near-mythical IBM color MDA

Eric Schlaepfer schlae at gmail.com
Thu Aug 23 22:31:43 CDT 2018


I'm not that lucky! But yes, an early card with the light pen connector
should work.

The card I used for the demo is a somewhat later revision. I added rework
wires to match the schematic in the technical reference manual of the
earlier revision.

With either an early MDA card or a modded card, if you fire up DOS 5.0 and
have QBASIC, you'll find that the COLOR statement... just works! It's quite
strange.

On Thu, Aug 23, 2018 at 8:24 PM Fred Cisin via cctalk <cctalk at classiccmp.org>
wrote:

> On Thu, 23 Aug 2018, Ali via cctalk wrote:
> > Which revision MDA is this? I have an original NEC Multisync and I have
> > a tone of MDA cards including one in one the first 5000 IBM 5150s
> > produced. I would love to get color out of it just for the sake of doing
> > it. Do you still have your demo programs?
>
> Do any of yours have the 6 pin Berg connector near the top of the mounting
> plate?  Some did.   On CGA, that connector is for light pen.
> Supposedly some early MDAs had pins 3,4,5 connected (not connected in
> later ones).  That MIGHT be the same ones as have the light-pen?
> connector.
>
> https://www.seasip.info/VintagePC/mda.html#cmda
>
> http://www.minuszerodegrees.net/5150/early/5150_early.htm
>


More information about the cctech mailing list