| Pin | Pin Name |
Description |
| 11 | +3.3V | |
| 1 | +3.3V | +3.3V/RS in Deskpro EN |
| 12 | COM | |
| 2 | +5V | |
| 13 | COM | |
| 3 | +5V | |
| 14 | COM | Aux COM in Deskpro EN |
| 4 | Fan OFF | may be +3.3VSB in some server PSU |
| 15 | +5VSB | |
| 5 | +12V | |
| 16 | +3.3V | |
| 6 | -12V | |
| 17 | COM | |
| 7 | PS_ON | |
| 18 | COM | |
| 8 | COM | RTN/RS in Deskpro EN |
| 19 | COM | |
| 9 | -5V | |
| 20 | +5V | |
| 10 | +5V |
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 chips Vcc to 5VSB and GND to GND. Cut PS_ON, and hook the motherboard side to an inverters input, and the PSU side to the inverters output. Then tie all remaining pins to ground. An Inverted PS_ON signal is also common in G3 iMacs.
correct
incorrect