First post, by thp
I got my hands on an IBM Aptiva 2168-857 (66MHz Intel 486DX/2). I wasn't able to fully test it yet due to lack of drives. However, it POSTs and I can get into the BIOS setup, but sometimes it just switches off and on again randomly, I suspect (hope) it's the power supply.
Checking inside, the power switch on the front doesn't seem to be a normal AT power switch - it goes (2 wires) to the mainboard, and there's an additional 3-pin connector going from the main board to the power supply. The power connection (power supply to mainboard) seems to be standard AT.
What is the pinout for the 3-pin connector? Would replacing the AT power supply with an ATX power supply (with ATX-to-AT adapter) (and NOT connecting the 2-pin power switch and 3-pin motherboard-to-power-supply) connector work, or do these IBM boards "require" the 3-pin connector to the power supply to function?