Dell OptiPlex GX520 User Manual page 152

22 VCC (+5V) Red
23 VCC (+5V) Red
24 GND Black
*Use 22-AWG wire instead of 18-AWG wire.
DC Power Connector P2
Pin Number Signal Name 18-AWG Wire
1 COM Black
2 COM Black
3 +12 VDC Yellow
4 +12 VDC Yellow
DC Power Connector P3
Pin Number Signal name 18-AWG Wire
1 +12 VDC Yellow
2 COM Black
3 COM Black
4 +5 VDC Red
DC Power Connector P4
Pin Number Signal Name 22-AWG Wire
1 +5 VCD Red
2 COM Black
3 COM Black
4 +12 VDC Yellow
DC Power Connector P5 and P6