IBM 5160 with oddball MDA input/output card

Ray Jewhurst raywjewhurst at
Fri Jul 26 15:21:48 CDT 2019

I have been out of the PC tech game for almost 20 years and even I know the
difference between ISA, PCI, MCA and AGP. I've never actually seen an EISA
in the flesh though.


On Fri, Jul 26, 2019, 4:04 PM Paul Berger via cctalk <cctalk at>

> On 2019-07-26 4:53 p.m., Fred Cisin via cctalk wrote:
> > On Fri, 26 Jul 2019, Jules Richardson via cctalk wrote:
> >> Someone on one of the Facebook vintage groups found an IBM 5160 with
> >> an MDA display for sale in Australia, except that it's a bit odd in
> >> that the machine had what appears to be an MDA card, the output of
> >> which is then connected via a short external cable to the input on
> >> another card, and then an output that card is what's actually hooked
> >> up to the monitor.
> >>
> >> The only internal photo of the machine is very poor, unfortunately.
> >> I'm reasonably confident that the "first" card in the "mystery" chain
> >> is MDA, it's full-length and alongside the DE-shell video output has
> >> the usual DB-25 for parallel. The "mystery" card is also full-length,
> >> and there's another full-length card immediately adjacent to it with
> >> no external connectors - that one could easily be RAM, or the hard
> >> disk controller etc.  but I suppose it's possible that the mystery
> >> item is actually a two-card set.
> >>
> >> Anyway, any guesses as to what it might be? The implication is that
> >> the mystery card adds functionality to the MDA card (reminiscent of
> >> 3DFX boards years later), but of course is operating within the
> >> confines of what the MDA display's capable of.
> >
> >
> > Genlock?
> > MOST video add-ons were combined onto a board with their own video
> > card, rather than connecting to IBM's
> >
> > Co-processor?
> >     Diamond Computer Trackstar was an Apple2 on an ISA card. It was
> > even sold [briefly] by Radio Shack.
> >     Quadram Quadlink was an Apple2 on an ISA card.  The college bought
> > 20 of them.  14 were DOA.  8 of the replacements ("THESE ones are
> > thoroughly tested") were also DOA.  One had a connector (right angle
> > dual row?) mounted backwards, and could not be connected for testing.
> >
> > But, MDA (or MDP as described) seems less likely.  "Who would want to
> > do Visicalc or word processing without COLOR??"  There did exist a few
> > after-market CGA cards that had DE9 and DB25 (printer).
> >
> >
> > Was it in working order?  Or had somebody merely cabled the MDA video
> > to a DE9 serial port?  And 5151 will physically connect to CGA (and
> > not work)
> > We had a couple of "instructors" at the college who didn't see
> > anything wrong with connecting any cables that fit, including swapping
> > bus mouse and video, or wanting gender changers to try to connect a
> > parallel printer to a 25 pin serial port ormodem to printer port.   It
> > is frustrating to try to deal with some people.
> I know of a "trained" service technician who inserted an PCI card into a
> ISA card slot and then call for assistance because it did not work.
> Fix.. swap technician...
> Paul.

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