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Adding an ISA slot

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Raddit123

Experienced Member
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Feb 14, 2015
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Hi all,

So a while ago I bought a computer (Early 2000s, Celron single core, 700mb RAM) for a whole £2 off ebay. It has several PCI lanes on the motherboard, and notably the space for an ISA slot, however nothing was ever soldered in to it.

My question therefore is, if I soldered an ISA slot into this space, would it work? I'd quite like to get an old MFM drive spinning up on this machine to see if it actually works + various other things..

Thanks in advance guys.
 
Which chipset do you have? Some later chipsets lack support for ISA slots and you would need a PCI-ISA bridge chip. No slot means also probably no bridge chip. Does the ISA slot have traces running to it? Can you find a generic BIOS for the system? Too many unknowns.

I didn't have success trying a MFM controller in a 2000 era system but I might have done things wrong.
 
Likely that you're missing a bridge chip. I've got a P2-era motherboard here with a large connector on the side made to accommodate an ISA slot adapter--but the bridge chip there is on an adapter. I suspect that populating your board for a bridge chip, adding the BIOS support, etc. would cost you far more than the board's worth.
 
Well you don't have much to lose either. If no obvious unpopulated chips are missing, solder an ISA connector in and see what happens, that's what I'd do.
You might get lucky.
 
Not necessarily. Many (if not most) ISA MFM controllers allowed for placing that BIOS extension in something other that the C800:0 location. The conflict very often was due to I/O address issues. You should, however, be able to mix an 8-bit ISA MFM controller with a standard (16 bit) MFM controller. The port addresses are different.
 
Hi All,

Thanks for the replies, one of the MFM drives is a 1988 NEC D5147H packing a massive 66MB, this thing is huge at 5.25", especiialy when compared toteh 2.5" drive on top of it; the other one is in a system at the min and will be something similar.

So I've had a look inside, there are tracks going to the ISA slot, however there is a missing chip that near by that leads to the ISA slot (see pics). Chip set wise, the BIOS goes on about a 786 or something, not sure if that's what you're after?

12899982_10205969669787526_49408834_n.jpg12899982_10205969669787526_49408834_n.jpg11100007_10205969669747525_1007932876_n.jpg
 
Raddit123 said:
Thanks for the replies, one of the MFM drives is a 1988 NEC D5147H packing a massive 66MB, this thing is huge at 5.25", especiialy when compared toteh 2.5" drive on top of it;...
Click to expand...
Actually, that drive is RLL, not MFM, so if you use it with any MFM controller it will only be 44MB.

Also, it's only half height -- a full height would (obviously) be twice as big. :)
 
Thanks for all the info guys. Never new about RLL. I think I'll leave my motherboard well alone in that case.
 
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