IBM PC 350 power supply

[tmadushan]

Do not I need to switch the PSU on??

[Neo]

On AT no. When you switch it on, power unit starts. On ATX, the motherboard should give a pulse to two pins on the ATX cable. However I agree with you, IBM (also other branded ones such as Dell) power supplies are too incompatible. So they might have put the wires going to power on of switch through motherboard. It looks like you need to trace from the motherboard.

[tmadushan]

Thanks bro. Im gonna try it