|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. Then 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. Then tie all remaining pins to ground. An Inverted PS_ON signal is also common in G3 iMacs.