Skip to main content

Model A1311 / Mid 2011 / 2.5 & 2.7 GHz Core i5 or 2.8 GHz Core i7 Processor

429 Questions View all

PSU power on signal

I’m trying to to use the iMacs PSU to build a mini-itx hackintosh.

Is it possible to use the power-on button in the iMac and then somehow connect it to the PSUs pin12, which should be the power-on signal?

PSU pin-out: Power Supply (PSU) pin-out diagram

I have removed the main board to make room for a display converter board to use the screen as a monitor, so I need to connect the power-on button directly to the PSU if possible.

Answer this question I have this problem too

Is this a good question?

Score 0
Add a comment

1 Answer

Are you using the Apple power supply or the one that came with your conversion kit?

You will need to emulate the circuit Apple uses on the logic board which feeds the Apple power supply the power on signal. Remember this is a soft power button, it is a momentary switch driving a signal line low (chassis ground).

Was this answer helpful?

Score 0


Hi Dan


I want to use the Apple power supply for the entire Mini-ITX build. Currently, I’m using an external power brick to power the screen, but if I can get the Apple PSU to power up I want to switch to it.

Yes, I figured its a soft power button. Question is:

Does the PSU power up if I just connect Pin 12 to ground?

IF this works, how can I then turn the soft power button signal into a permanent signal for the PSU to remain on?

Does the PSU require any load like a normal ATX PSU, where a small 10-20W resistor can be applied to the 5v rail to emulate the motherboard (seen here:


You'll need to experiment!

I have not dug that deep into the circuit and its not documented any where.


Add a comment

Add your answer

Justice will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 0

Past 30 Days: 3

All Time: 67