Electricity went out while operating computer and now it wont power on

4evrnyt

Honorable
Apr 25, 2012
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10,510
Today the lights dimmed mementarily and then the power went out for a couple of minutes. When it returned my PC was dead. It was running just fine before the outtage. Nothing happens when I hit the power button, the mobo has a pwr switch and it also does nothing. I disconnected the psu(ocz 700w), grouned out the 24 pin connector and turned on the psu and the fans started. I put a multimeter on the rails and all of them read fine except the 12v's all read 11.3. Is 11.3 enough to at least power up the system or not?
If that voltage should be at least enough to get to bios then I'll have to assume that the motherboard itself has been damaged.

Thanks for your help. Considering running to BestBuy and grabbing a psu to just see if that fixes it or not.


Incase it matters the rig is a i5-2500k(stock), ocz-gxs700 psu, 8gb, hd6870. The computer is plugged into a decent surge protector but not currently using a ups.
 
If your voltage is more than 5% off, the PSU is considered to be functioning improperly. For 12V, that means it should be between 11.4V-12.6V. So long story short, yes, it appears there's reason to be worried that your power supply was damaged.

I would try to swap it out for another one and see if the system will start. When the PSU blows out, the damage could be anything from just the power supply itself, up to everything in the whole system. If you're lucky, it damaged the PSU and nothing else.
 

4evrnyt

Honorable
Apr 25, 2012
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10,510
OK so this is one of the most weird situations I've ever experienced with a computer. After confirming the voltage was in fact fine under load I ordered a new motherboard. It's been nearly two weeks since the computer stopped working and the new motherboard is due to arrive tomorrow. While sitting next to the machine this afternoon it decided to turn itself on. Now can someone please explain to me what the heck is going on? The computer fired itself up, and seems for the most part to be working fine other then it now gives me a CMOS failure message upon reaching the bios screen but will still boot to desktop and function just fine. I'm assuming the CMOS message is from a dead or dying battery but at this point I should stop assuming things. I'm certain that I will replace the motherboard anyway when the new one arrives but I would very much like to know what people think would have put my computer into a 'coma' for the past two weeks and then have itself literally turn itself on.
 

dedekind

Distinguished
Apr 14, 2012
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18,690
Well, most likely, if you hadn't ordered a new motherboard, then the old motherboard would have never worked again. This usually happens, and sometimes the only explanation is bad luck.

There should be a technical reason, but it doesn't rule out the bad luck!

EDIT: now that I'm here, what do you people recommend for an UPS? I have a PPC Silencer 760W PSU, but I have no idea what UPS should I get. I just want something to be safer in these situations.