Here is the Pinout for the Female XBOX 360 Power Connector. I tracked down this information from: Llamma.com
Specifically it is on Page 9 of the pdf, but be aware that this document contains an error
. Under the Note: it states that "Pin 7 Turns Pins 4, 5, 6 on when it is tied to ground" but this is incorrect.
Power is enabled when 3.1V
is fed to Pin 7 when measured directly from my 360 motherboard. I have done further testing and found that ~1.5V to 5V
will enable the power (aka the green light activates and you get +12V).
As a result of my testing i found that one can easily enable the power supply on by wiring a switch between the +5VSB and the PWR ENABLE Pins