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Old 02-17-2013, 09:42 PM   #1
miketen587
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Default Had Power Outage...Now PC will not start

Earlier this afternoon, apparently there was a power outage at my house. I wasn't home, but my girlfriend told me the power flashed on and off a couple times pretty quickly.

After the first outage, she shut down my PC thinking she was doing some good, now it will not turn on.

It was plugged into a surge protector at the time. Everything else plugged into the surge protector is working fine.

When I flick the power switch of the PSU on and off, the green light on the mobo turns on and off accordingly.

Does this sound like a fried PSU? What should I do?
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Old 02-17-2013, 09:56 PM   #2
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Surge protectors protect components from voltage spikes but not undervoltage, which occurs during brownouts. So, if the lights go dim, this is when undervoltage would occur.

It could be either the PSU or motherboard. You will need another good PSU to see if the PSU got toasted.
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Old 02-17-2013, 10:04 PM   #3
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Post the specs for your PC. The green LED indicates the mobo is powered and when you turn off the PSU switch it should remain lit for several seconds afterward, until any residual voltage dissipates, and then go out. Does it stay lit for a few seconds after you switch off the PSU, or does it instantly go out when you flip the switch?
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Old 02-17-2013, 10:07 PM   #4
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Thanks for the reply.

I'm just a little confused as to why the green light on the mobo turns on and off when the PSU is switched on and off. Would this indicate the the mobo is ok?

I really hope its not the mobo. I'll have to go pick up a new PSU tomorrow and give it a whirl.
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Old 02-17-2013, 10:25 PM   #5
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Posting the specs for your PC, and providing some feedback as to your result of trying the suggested diagnostic steps, will make this a lot easier.
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Old 02-17-2013, 10:37 PM   #6
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Ok so I actually had an old PSU lying around...it only has one 4 pin connector to the mobo as opposed to the 2 4 pin connectors my mobo requires. I just connected the 1 connector and obviously the 12 pin main connector, and it fired up a couple of my fans. I turned it off right away however because I wasn't sure whether or not it would be safe keeping it on for any amount of time with only that 1 4 pin connector.

Does this hopefully isolate the PSU as the problem?

My Specs are:

CPU: i5 3570k
Mobo: Asus P8Z77-V LX
PSU: Coolermaster Extreme Power Plues 700w
GPU: GTX 670
RAM: 8 gigs
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Old 02-17-2013, 10:38 PM   #7
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Also, the green light on the mobo stays lit for a few seconds.
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Old 02-17-2013, 10:58 PM   #8
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That's a good indication that the mobo is OK (but not a guarantee). Don't attempt using an old PSU not designed for a modern board; wait until you can test a suitable PSU. In the meantime; it wouldn't hurt to unplug, inspect, then reseat every single connection including all the front panel (power button, usb, etc.) wiring connectors.
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Old 02-18-2013, 10:35 AM   #9
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With your old power supply, when you press the power button, look carefully at the PSU exhaust fan.

If, when you press the button, you see the fan budge for a second and then stop, then you likely have bad capacitors in the PSU.

This is the way I see most PSUs fail. Sometimes you have to push the button a couple of times to get them going, and when they're on, they work fine. Then, one day, it just doesn't turn on anymore. I personally wouldn't run one of those PSUs thats failing but I see plenty that do.
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Old 02-18-2013, 02:39 PM   #10
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Thanks for the advice and replies everyone. It was indeed the PSU. I went to microcenter earlier and picked up a Corsair CX600. I'm completely back in business.
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Old 02-18-2013, 06:38 PM   #11
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Quote:
Originally Posted by miketen587 View Post
Thanks for the advice and replies everyone. It was indeed the PSU. I went to microcenter earlier and picked up a Corsair CX600. I'm completely back in business.
Might be a good time to invest in a decent UPS as next time, you might not get off so easy.
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Old 02-18-2013, 08:59 PM   #12
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Quote:
Originally Posted by Steltek View Post
Might be a good time to invest in a decent UPS as next time, you might not get off so easy.
No doubt about it. I actually have a spare one at work that I will be taking home with me tomorrow. I've been meaning to take it home for a while now and just haven't. Probably could have saved myself a few bucks had I.
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Old 02-18-2013, 11:12 PM   #13
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Quote:
Originally Posted by miketen587 View Post
No doubt about it. I actually have a spare one at work that I will be taking home with me tomorrow.
Another power cycled a computer that failed. Then I did a PSU analysis (got the PSU working). Due to too many hours of operation, a bootstrap resistor failed. Resistor's only useful function is temporary power during power on. It probably failed months earlier. But that defect was only apparent when the PSU power cycled.

Using observation, they blamed power cycling. Actual failure was created by too many hours of operation. They left it always on.

What will avert your failure? Nobody can say without such details. But a UPS typically does not extend electronics life. Its purpose is temporary and 'dirty' power during a blackout. So that unsaved data can be saved. Better is to power off (ie hibernate) when done for the day.
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Old 02-22-2013, 01:47 AM   #14
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Quote:
Originally Posted by miketen587
Thanks for the advice and replies everyone. It was indeed the PSU. I went to microcenter earlier and picked up a Corsair CX600. I'm completely back in business.
Im glad ya got things corrected buddy.. Im sorry you went thru this!
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Old 02-22-2013, 10:45 AM   #15
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Quote:
Originally Posted by westom View Post
Another power cycled a computer that failed. Then I did a PSU analysis (got the PSU working). Due to too many hours of operation, a bootstrap resistor failed. Resistor's only useful function is temporary power during power on. It probably failed months earlier. But that defect was only apparent when the PSU power cycled.

Using observation, they blamed power cycling. Actual failure was created by too many hours of operation. They left it always on.

What will avert your failure? Nobody can say without such details. But a UPS typically does not extend electronics life. Its purpose is temporary and 'dirty' power during a blackout. So that unsaved data can be saved. Better is to power off (ie hibernate) when done for the day.

yes. turn off your devices when needed. most capacitors inside computer components have a 2000 hour rated life last i checked... of course most people get a lot more then that out of them, but they arent working to what they were rated at after that point.
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Old 02-22-2013, 08:13 PM   #16
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Theres was a long thread some months ago about leaving computers on all the time to possibly lengthen the life of harddrives and that had quite a number of proponents.
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Old 02-23-2013, 09:32 AM   #17
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Theres was a long thread some months ago about leaving computers on all the time to possibly lengthen the life of harddrives and that had quite a number of proponents.
Most people only believe the first thing they are told. And rarely demand what is always required to have knowledge: the reason why with numbers. Same reason why so most in the 1950s believed smoking cigarettes increases health.

Power cycling is destructive. And then we apply numbers to that claim. Power cycle a disk drive seven times every day for .... 39 years .... to do damage. The niave know by ignoring numbers. After 39 years, a disk drive has been replaced how many times? Power cycling is destructive when myths, subjective reasoning, and knowledge from emotion replaces what everyone was taught in elementary school science.

Why PSU failures? Is a power outage destructive? Of course not. But so many will use observation. See a failure after a power outage. Then assume power outages must be destructive. Total nonsense. But so many know power cycling must be harmful even to disk drives.

Last edited by westom; 02-23-2013 at 09:35 AM.
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