how do you hack an AT power supply?

[krkchn 0]

I need a power supply for use for my circuitry project since it has 5V and 12V. I currently have an AT power supply but the problem is that it automatically turns off when not connected to a motherboard. I need a circuit hack of sort to make the supply constantly turned ON. I appreciate any help.

[felix 0]

I think you mean an ATX supply.

 

The ATX supply design is "always on" with a relay start switch which then closes the circuit.

 

You would be better using an AT supply that has an actual switch which controls the power and was used in older systems.

[jmmijo 1]

If this is indeed an ATX power supply, then check out the specs at THIS site for more info. Look at section 3.3.2 for the PS_ON# pin which needs to be an active low

[AndyFair 0]

In other words, if you connect pin 14 (old-style 20 pin connector) or pin 16 (new style 24-pin connector) - green wire - to any ground connector (black wires), the PSU will start - as long as the power lead is plugged in

 

[jmmijo 1]

Originally posted by AndyFair:

Quote:

In other words, if you connect pin 14 (old-style 20 pin connector) or pin 16 (new style 24-pin connector) - green wire - to any ground connector (black wires), the PSU will start - as long as the power lead is plugged in

 

Correct