HELP Comp wont turn on anymore

[jibbajoe0129]

Its my first week back at college and last night my computer started shutting down randomly, almost like the power flashed, but it didnt. the first time it happened i was able to turn the system back on and it worked for maybe a half hour then it turned off again. it would sometimes turn on again but only for a few seconds, it wouldnt even get to loading windows and it would shut down again. This morning it wont turn on at all, not even for a moment. I was able to see during the few seconds it ran last that all the fans were moving, PSU, CPU, and all the others. Last semester i was having similar issues where the system would randomly turn off but i went home for christmas break and bought a brand new Corsair HX750, and everyone was working perfectly fine. Before i thought it was a PSU issue but i dont know anymore. Power IS getting to the board. the LED on the mobo lights up and the external harddrive i had plugged in would also be on, but the computer wont boot. I dont know if its important but when the computer did boot up again after turning off it wanted to run a disk check which i let it do. Heres what ive tried

Different outlets
unplugged everything from the system except power
ive unplugged all of the hard drives to see if it would turn on but nothing
i unplugged the whole system and waited overnight but still no boot
I had hardware monitor running one time before it shut off but nothing was overheating

Heres whats inside
3 HDDs nothing fancy
1 dvd drive
AMD Phenom II x2 555 O.C.@ 3.7
Sapphire HD 6870
4gb Gskill
ASUS M4A79XTD EVO mobo

Like i said, i had no issues at home and ive had my cpu overclocked for a while and have never had an issue.

 

[o1die]

The board or power supply may have decided it didn't jive with your overclock. This can happen without warning even if the overclock was working fine for awhile. I would reset the bios by removing the board battery with the power supply unplugged. Then try posting again.

 

[jibbajoe0129]

When you say unplug the power supply you mean just from the wall right? i dont need to disconnect it from the mobo? assuming that is the case, i just tried this, and still nothing. The light on the motherboard turns on but still no boot

 

[o1die]

Yeah. Either unplug from the back of the case or wall socket. I would try a different ps first. I use antec or ocz ps. Both are pretty affordable and reliable.

 

[jibbajoe0129]

So i used to have a Corsair 500W last semester when i was having similar issues. over christmas break i got the Corsair 750W and it worked perfectly fine at home. then 4 days after coming to school it shits the bed and you still think it could be the power supply?? i know antec and ocz are good but Corsair is like THE name in power supplys. And just to say it again, the mother board is getting power.

Do you have any other ideas? could i be getting bad power from the outlets?

 

[jibbajoe0129]

So i was going to try to test my power supply today with a multi-meter, but when i tried shorting out the power on wire with a ground wire the PSU would not turn on(the fan would never start spinning), assuming i did this correctly, the green power wire to any black wire on the 24pin connector. Does this mean my PSU is dead?


Also i checked the voltage accross the green and black wire and got just barely over 2v

 

[jsc]

Sounds like a bad power supply if you have disconnected the PSU from the motherboard and everything else.

The green wire is a control line going to the PSU. As long as the PSU switch is turned on, it sould have 5 volts on the line. It should drop to 0 when you press the case power switch.

What do you measure on the violet wire? Should be 5 volts as long as the PSU switch is on.

 

[jibbajoe0129]

i measured 5 volts on the violet wire but only 2-2.5 ish volts across the green wire, but i still cant short the green wire to get the supply to turn on.

 

[jibbajoe0129]

Best answer selected by jibbajoe0129.

 

[jibbajoe0129]

New PSU from corsair solved the problem