This pinout is as standard ATX v.1 Except for PWR_OK and PS_ON.
20 pin MOLEX 39-01-2200 connector at the PSU cable.
|1||+3.3V||+3.3V/RS in Deskpro EN|
|14||COM||Aux COM in Deskpro EN|
|4||Fan OFF||may be +3.3VSB in some server PSU|
|8||COM||RTN/RS in Deskpro EN|
- A Compaq SP750 Server Power supply (Such as PS 7431-1) uses the same pinout as an ATX power supply, except that PS_ON is inverted, and PWR_OK is replaced with 3.3VSB. The wire colors are also different.
- To use this supply with a normal ATX motherboard:
- cut PWR_OK and tie the motherboard side of the wire to 5v
- leave the power supply side of the wire unconnected
- use an inverter such as a 4096 or 7404 to fix the PS_ON signal
- tie the chip’s Vcc to 5VSB and GND to GND
- cut PS_ON, and hook the motherboard side to an inverter’s input, and the PSU side to the inverter’s output
- tie all remaining pins to ground
- An Inverted PS_ON signal is also common in G3 iMacs.