Bummer.

If you can confirm it's a 1:1 perfect a/b swap:

Wouldn't it be correct if the slot was on the back?
I'm not loving the chance of no other fallout.

https://upload.wikimedia.org/wikipedia/common … SA_Bus_pins.svg

It looks like the data/address lines on the gus would get the brunt of it, but who knows where it was trying to earth

myne wrote on 2025-07-24, 07:26:

Bummer. […]
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Bummer.

If you can confirm it's a 1:1 perfect a/b swap:

Wouldn't it be correct if the slot was on the back?
I'm not loving the chance of no other fallout.

https://upload.wikimedia.org/wikipedia/common … SA_Bus_pins.svg

It looks like the data/address lines on the gus would get the brunt of it, but who knows where it was trying to earth

No biggie. We will get it soon. My wife is really pushing me now to finish it after seeing it being recognized in WinXP. Guess this is a full time project job now.

Yeah it's a perfect A/B swap, and you're right it would work on the back. Great idea! You saved me a bunch of soldering.
Well, there's only one way to find out, and we'll just keep fixing things until there's nothing left to fix!

For the GUS I believe the ISA8888 card sent -/+12v to U1 and earthed through the same chip. Or so I think based on tracing the traces on the GUS, might be wrong on that.

Lol good attitude at least

Ah yes, that ISA pin/sides numbering, It also seemed weird to me and I tend to swap it in the past but I double checked, measuring on a real card in hand, checking again... But on some other project I flipped pin numbering on display FFC cable (I temporaly solved it by manufacturing aux FFC cable that flipped it back choosing top/bottom contacts side, JLC can do cheap flexi PCBs now)... seems no one could avoid this kind of errors...

But in your case the fix would be very easy. Just remove the ISA slot by hot air and solder it on back side of the PCB. I see there are no components on back side that would collide, maybe that few elyts - you can solder some with a bit longer wires to move them along the slot. As you have the card on cable riser it mechanically doesn't matter on which side the ISA slot is... 😀 EDIT: heh, it was already told, just refresh the page...