How to enable PC supply as 12V DC power source?

[anne]

I have unlabelled PC supply - about 3 x3 x10 inches - with standard Molex plugs and 2x10 connector.
I have read somewhere that to use PC power supply it has to be "enabled" by hardware connection.

Could somebody give me a hint what to ask Mrs Google ?

I need 12V DC supply for NOT powering amateur equipment.

PS I believe the 2x10 plug has standard PC designation - such as J xxx.

[gnuuser]

a pc power supply is a switching power supply and can often make a lot of unwanted electrical noise in radio equipment.
If I remember correctly
what needs to be done with an atx supply is to locate the power good wire and add a switch to it to ground, this will turn the power supply on!

one of the 5 volt positive wires needs a 5 ohm 5 watt wire=wound resister to ground.
and last there is a couple small pots on the board you may have to adjust to either raise the voltage to 13.5 volts or 12.8 volts
there are various videos on you-tube on how to do this.

a 400 watt supply producing 12 volts will provide 33 amps of current

an at power supply however does not have a power good circuit, but you need the switch from the case taking care to reconnect the wires exactly as they were or risk burning the supply up. these type supplies were in win 95/98 era and earlier.
yellow wire was 12 v+ black was ground, red was 5 volt +
in atx orange wire was 3 v+

[whit]

I don't know if you've found what you're looking for yet or not but try doing a search for "ATX Power Supply to Benchtop Power Supply". There's also a decent post on the Dronebot Workshop on Youtube.