View Full Version : AT power switches

January 27th, 2014, 09:54 AM
What type of switch is a standard AT power switch? Just from looking at it, it looks like a standard DPDT latching on/off switch. Is there anything special about it, or would any latching/rocker DPDT switch technically work for this application? I need one for testing a bunch of old AT motherboards I have lying around.

Also I'd like to use the switch with an ATX power supply with an ATX-to-AT adapter, but the adapter only has black/green leads for the power switch. IIRC most AT power supplies have brown and blue leads as well. Where do the green and black go on the AT switch, and am I going to need some other wires/parts to make it work?

January 27th, 2014, 10:18 AM
Yeah it's a standard switch - either ON or OFF - nothing fancy. But mains voltage runs through it, keep that in mind, so you'd want one rated for 110 or 220V (depending on where you live) and make sure it's mounted so you don't accidentally short the pins with your fingers.

For ATX supplies - mains voltage is always applied, but the PSU stays off unless the green wire is shorted to ground.
For AT supplies - you switch the mains voltage (110V) - just like you might turn something ON or OFF at the wall - Brown/Blue carry 110V or 220V (depending on where you live)

To use an ATX supply on non-ATX motherboards - you connect green and black to a switch.
Although the last time I did this, I just shorted green/black, and kept the original AT switch at mains voltage - because in that situation it was less hassle.

January 27th, 2014, 11:36 AM
DPST, no? What would the other DPDT throw position be used for?