IBM 5160 with oddball MDA input/output card
phb.hfx at gmail.com
Fri Jul 26 15:04:16 CDT 2019
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.
> MOST video add-ons were combined onto a board with their own video
> card, rather than connecting to IBM's
> 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...
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