Built PC - Won't power on beside 4-pin +12 volt power connector plugged surrounded by to motherboard?

This is exotic to me - I built a PC and plugged in adjectives connectors and my system wouldn't turn on. I noticed it powered on the enthusiast and power supply for less than 1 second after turned off. I get the same result near a different power supply.



Then as I was using my power supply tester I notice the power supply didn't work, but it did work when I unplugged the 4-pin 12-volt power connector going to the motherboard. After I unplugged the 4-pin connector all is in good health. The system turns on, bios indicate fans and temp are correct, cpu running at the right speed, it boots up, no problem.



Any Ideas as to why this is happening?



My system -



Intel Celeron D 360 3.46ghz, socket 775 cpu

Mach Speed P4MSD-800D2 Motherboard

512 MB Ram

550 watt power supply

Built PC - Won't power on beside 4-pin +12 volt power connector plugged surrounded by to motherboard?

Sounds hugely much like a short. If you own access to a storage oscilloscope you can find out which of the power lines isn't coming up.



Another alternative is that the power supply is bad and simply can't whip the load once it is plugged within.



If you don't have a range:

- Reseat everything!

- Find another power supply to try.

- Replace the motherboard.



Come to think of it, you own pushed the soft power-on button? Some motherboards can be configured to not turn on when power is applied. They require the soft power button to be pushed.

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