IBM 5160 with oddball MDA input/output card
jules.richardson99 at gmail.com
Fri Jul 26 17:15:34 CDT 2019
On 7/26/19 2:53 PM, Fred Cisin wrote:
> MOST video add-ons were combined onto a board with their own video card,
> rather than connecting to IBM's
It seems odd within a 5151/MDA context though - plus the system seems
entirely self-contained, i.e. not designed to interact with any other video
> 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.
Something like that is certainly sounding plausible to me - not necessarily
Apple II, but *something* that provides non-x86 processor ability, and
presumably which involves video output above and beyond MDA (otherwise why
wouldn't it drive the MDA card directly), and yet still monochrome and
compatible with a 5151.
> 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).
I did manage to locate the original seller's listing, which didn't really
provide any new information - but there were a couple of pictures of the
monitor confirming that it is a 5151.
> Was it in working order? Or had somebody merely cabled the MDA video to a
> DE9 serial port?
The thought had crossed my mind, too. Seller's claim was that they had it
booted to a DOS prompt, then smoke came out of the PSU; if they're honest
then it's likely age-related demise of RF suppression caps or maybe a
I did get the impression that they don't really know what they have, i.e.
to them it's just an old XT (and therefore worth a small fortune).
The cable connecting the MDA's output to the mystery card does rather look
like it was made for the purpose - it's conveniently long enough to bridge
between one or two slots, and the cable appears to exit the connectors at a
45 degree angle to account for the MDA's output being toward the top of the
card while the input to the mystery card is toward the bottom.
> 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 suppose that's the only good thing about the modern "everything is USB"
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