Sign in with
Sign up | Sign in
Your question

Problem When I Plug In 4 pin ATX 12V

Last response: in Motherboards
January 24, 2010 8:34:50 AM

Everytime i plug in the 4 pin ATX 12V the comp boots up for 2 seconds and keeps shutting down.

When i remove the ATX 12V the comp seems to boot up and stays on, all fans going.
tried with just running power supply, cpu with heatsink, but everytime i switch it on it cuts off after 2 seconds.

No post beeps. Power supply is checked and changed as well.

January 26, 2010 3:42:56 PM

System specs:
Gigabyte GA-8IR2003
Intel Celeron 1.8 GHz
PSU : 400w and 500w

I am sure that the PSU is not bad. Because i have already changed the PSU and checked the voltage reading of yellow and red wires through multimeter.

BTW my one is not a new build PC. Its running from 2003 onwards and all of a sudden this happened. So is it for a bad CPU or motherboard. Any way to be sure of it? Is there any chance that a bad CPU would resist the motherboard to supply power??

Thank You
Related resources

Best solution

a b ) Power supply
a b V Motherboard
February 9, 2010 7:12:35 AM

Have the same problem on an ECS P4M800-PRO.

Plug in ATX_12V (4pin) with the ATX2.x 24pin and computer boots for 1sec and dies. Disconnect the ATX_12V and the computer powers on, but does not go into POST. Previously, computer was running fine until it needed a windows update--it auto-rebooted and died. Was a CCTV server with about 2 yrs uptime.

Just replaced it with an Biostar board and it POSTs & boots. So, conclusion was it was the motherboard--likely the regulators were shot. What I hate was I had a 3.2Ghz PentiumD (was nice), and thought it was the CPU, so I got a cheap Celeron E3200...somewhat a waste since it appears the CPU is good. Also, the old MB had DDR ram, and the new MB only uses DDR2 ram--so it's off to the shop again :(  Also, my nice AGP integrated graphics is now a paper weight since the new board as no AGP, but PCIe ... ugh. Oh well, it's going to be another $40+DDR2 memory to fix this problem...

Lessons learned:
+ Check P/S leds for voltage. Also if you ethernet light comes on, PS is likely ok.
+ If you can POST but no boot, it's memory or CPU (remove then and see if the bios reports the right errors)
+ If you get no POST/Beeps, it's the MB--even if it powers up, it's still the MB.
a b V Motherboard
February 17, 2010 1:03:26 AM

Best answer selected by r_manic.