Over the years, I've kept a few ATX power supply from old computers. Now, I'm thinking about upgrading my computer and add more hard disks. The problem is the current power supply might not be able to support so many hard disks running at the same time. Instead of buying a new, more powerful power supply, I am planning to use one old piece (350w) to serve the motherboard, CD, and 3 hard disks, then another power supply (350w too) to serve 3 to 4 more hard disks. All components are connected to the same motherboard. I need to know how I could turn on both power supply with a single press of the power button on the case.
In other words, only one power supply can plug to the motherboard, how can I jam the wires together so that the second power supply receive the power-on signal when I press the button? I was thinking about the Power-On (Green), Power-Good (Gray) and 5 VSB (Purple) wires. the second power supply would only support the hard disks and nothing else, but I need them to be powered up at the same time other hardware are up (and down when it's shut down).