AT Power Supply - Which wires to short/load to turn on power?

Started by omarspinouts, Aug 10, 2014, 09:30

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So everyone knows everything about ATX power supplies (and then some), but ask about the older AT power supply and you get people stumped.

So I am asking here... I have removed an AT power supply from an old desktop PC I have, hoping to be able to use it as a bench power supply.. etc. But I cannot figure out whether I need to short one power lead to ground or throw a resistor (load) on one to turn the power supply on. And if so, which wire gets shorted/loaded?

The cables that connect to the motherboard are perfectly described under this listing/link:

It has both the P8 and P9 and they do line up as described, with the black wires from both connectors are next to each other.

Thanks in advance to anyone who can provide any information.


As far as I remember AT PSU features separate cable with the power switch. It physically turns PSU on or off. It's impossible to turn them on via P8,P9 connectors.