New Power supply: P4 connector, boot issue?

Question

Hello
I've just replaced the power supply in my Gateway (420GR) due to a bad fan in the otherwise working old supply. With the new supply, the fans only spin-on (all case, cpu, and ps fans) only when the P4 connector is not attached. (the keyboard lights go on for a second as on reboot but then the mouse and keyboard show no life) When the P4 connector is attached, the fans begin to spin (for a very small moment) and then stop. In neither case does the system seem to boot.

This behavior is experienced with both the new power supply and the ond supply, but only after the old supply was re-installed. Before the supply upgrade, there were no issues with the system.

Does anyone have any idea what could be the cause of this issue?

Answer 1

When P4 connector is attached, your power supply seems to sense an overload condition and activates auto shutdown safety feature. Your unplugging and plugging connectors to the motherboard may have caused it to be grounded w/ the case. Try dismounting the motherboard and powering your PC w/ the board not electrically touching anything in the case.

Answer 2

Three possibilities come to mind.

1. It sounds like it could be a cabling issue. Either something's not plugged in that should be, or something is plugged in that shouldn't be. Don't know that motherboard or what types those power supplies are so I don't know what should or shouldn't be plugged in. I do know that my Intel board had two different ways it could be setup depending on whether you were using a PSU with a 24-pin motherboard connector or a 20-pin connector.

2. Something came loose while removing the old PSU. Check to make sure that everything from the video card to the CPU is properly connected/seated.

3. Worst case scenerio, when you removed the old PSU something happened to damage the system. (For example, did you unplug the computer from the wall and wait a minute before starting to unplug stuff? Did you use a grounding strap? Did you get a static electric shock at any time while working on the system?) Maybe, just maybe, the CPU's fried?

If you can't fix it yourself, I'd recommend taking it in to a computer repair shop and have them examine it.

Edit: Or try the above response 'cause he sounds like he knows a lot more about it then me.