Home made lab power supply?

Alright I dug out an old Dell 4600 ATX power supply. P-1 plug is the main board 20 pin. Position: lock tab up, wires in your hand towards you. From the right side, top row of wires. Count in 4 wires, it is a green wire. Only one in the loom. This PSU is in size approx. 3.5 X 5.5 X6 inches. Looked at the link you left, both types appear smaller. Would not think Dells PSU vender would swap wires around. Hope it helps.