Long story short, I have a CGA monitor and graphics card which I would like to use. The CGA board fits into an 8bit ISA slot, but I do not have a working motherboard with an 8bit slot, only 16bit ones. (Actually, I do have an XT clone, but no 360K drives to boot it with).
Is it possible to connect it to a 16bit slot? Does an adapter exist? I tried a search and couldn't find one.
It should just fit without any issue. 16-bit ISA is just an extra smaller bit of slot behind the 8-bit slot. The fact that you're asking this question and mention adapters suggests that maybe you're dealing with something other than 8/16-bit ISA?
Some 8 bit ISA cards won't fit because they have an edge were the 16 bit part of the connector is supposed to be
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Deksor wrote on 2020-06-18, 11:58:Some 8 bit ISA cards won't fit because they have an edge were the 16 bit part of the connector is supposed to be
Which is exactly the problem with the IBM CGA:
https://en.wikipedia.org/wiki/Color_Graphics_ … ics_Adapter.jpg
The OP could use an ISA riser, perhaps, but those most often also use 16 bit slots. So you would have to desolder one of them and replace them with an 8 bit connector (which can still be bought, e.g. at Mouser). But then you could also modify your existing board and downgrade one of the slots...
Ah I see, yes he could use an ISA riser or backplane Short on ISA slots? Try this. .
Here's an 8 bit backplane which you could connect with flat cables like in the thread I linked... good luck.
Oetker wrote on 2020-06-18, 12:11:Ah I see, yes he could use an ISA riser or backplane Short on ISA slots? Try this. .
That last photo is fantastic 😁
Deksor wrote on 2020-06-18, 11:58:Some 8 bit ISA cards won't fit because they have an edge were the 16 bit part of the connector is supposed to be
Yes, that is the problem with this card. It doesn't physically fit. I would have to downgrade one of the existing slots by replacing it. I'm in Australia, so parts like the ones in the other posts are harder to get without expensive shipping costs. I may be better off just buying an old motherboard.
"ISA riser" is the object I'm looking for. I figures something like that existed, but had no idea what it might be called.
Something like this might do it.
https://www.waste.org/~winkles/isaRiser.jpg
You can always desolder and remove the 16bit portion of the edge connector.
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appiah4 wrote on 2020-06-18, 12:55:You can always desolder and remove the 16bit portion of the edge connector.
You might have to saw it off. Some 16bit edge connectors are one piece. Especially on boards that only have 16 bit slots.
root42 wrote on 2020-06-18, 13:00:appiah4 wrote on 2020-06-18, 12:55:You can always desolder and remove the 16bit portion of the edge connector.
You might have to saw it off. Some 16bit edge connectors are one piece. Especially on boards that only have 16 bit slots.
True, some boards have the two edge connectors separate but most are joined and you may need to saw off the second slot after desoldering it, so that you can remove it. If you are careful and don't saw into the motherboard, the 8-bit slot would still work though. Of course, this is all academic - you shouldn't do it the lazy way I am describing here. Desolder the whole 16-bit connector and solder in an 8-bit connector. 😁
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Exactly. Like this one:
If the card doesn’t have chips in the region where it would contact you could just saw the “end” of the 16bit slot off and it would slip down inside
You would need to ensure nothing shorts out
the safest route is probably just getting an ISA riser that includes at least one 8-bit slot
