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Can't turn computer on after a power outage

by IAmMelinda / January 18, 2006 3:28 AM PST

My neighborhood lost power for a few hours this morning. When it came back on everything in the house was fine - except the HP desktop. It was not turned on when the power went out so I can't figure out why nothing happens now when I try to power up. It is plugged in to a battery back-up surge protector but everything else plugged into that goes on just fine right now. Any idea where to start. Thanks.


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First try unplugging the Computer's power supply
by Ray Harinec / January 18, 2006 4:24 AM PST

from the surge protector. Leave it unplugged for about 3 minutes, then plug it back in. Then try a normal turn on.

Doesn't work, then let us know of any powering up indications of any type that you detect when the problem is present. Any fAna, lights etc?

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No go
by IAmMelinda / January 18, 2006 5:29 AM PST

Nothing happens when I press the "on" button. There is a small faint green light next to the fan on the back that is blinking when the power cord is plugged in. But absolutely NOTHING when I try to turn the computer on. I was hoping it's not fried since it was not turned on when the power went out or came back on but I'm beginning to think I have a major problem.

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It's possible there was a large surge of
by retired / January 18, 2006 6:32 AM PST
In reply to: No go

current either when the power went off or when it came back on, enough to damage something. one other thing you can try is flip the switch on the back of the power supply to off for a few minutes, turn it back on and try again. If you have no experience on trouble shooting these you may to take it to a shop so they can check the power supply and go from there to other components.

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I need to know what state the computer
by Ray Harinec / January 18, 2006 7:14 AM PST
In reply to: No go

and the UPS was in when you say that it was off. First I am assuming that what you called a battery backup surge protector is probably a UPS [Uninterruptible Power Source]. If the computer was shut down by a normal windows shutdown and the UPS remained plugged into the 120 Volt line and the computer's power supply plugged into the UPS and the UPS NOT turned off, there would still be 5 volt standby voltage applied to the computer's mobo. ATX type computers never go completely off unless the power supply is turned off or unplugged.

The green light that you see is likely the LED that is lighted when the 5 volt standby is present on the mobo. The fact that is blinking seems unusual. HOPEFULLY it simply means that the power supply got zapped and simply relacing the power supply may fix the system. That 5 volts would have to on steadily for the rest of the voltages from the supply to turn on.

Power supplies are really not difficult to replace, except that to make nice little towers HP and the others pack the equipment in very tightly.

If you go to the HP website they may have a sequence of photos for your system showing how to remove and replace various items. I find the HP site provides much good info, at least for their computers of the last two years. You may get stuck having to buy a supply from HP rather than finding a substitute at much lower price elsewhere.

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I'll give it a try
by IAmMelinda / January 18, 2006 7:24 AM PST

Unfortunately I turned off the surge protector to stop the beeping and the power came back on during that time so I probably do have a zapped power supply. We've gone on to the HP site and are going through their troubleshooting process so hopefully will figure out what it is. I'll take it into a shop tomorrow if we can't figure it out. Just a stupid question since you're being so polite and helpful - if it is just the power supply that won't mean I loose everything on the hard drive will it? Haven't backed up in a while and have some recent new stuff I'd hate to loose. Thanks for you advice and I'll keep trying and update if I ever figure it out.


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With luck it will only be the power supply
by Ray Harinec / January 18, 2006 7:40 AM PST
In reply to: I'll give it a try

and it didn't take anything with it. To damage anything else the supply would have had to turn itself on.

I would think that the loss of the mobo [some parts on it] is far more likely than any damage to the hard drive.

If you take it to the shop tell them to unplug the drive while they troubleshoot, to preclude damge to the drive. A hard drive is not needed to do most of the troubleshooting they would do. Just the last check to be certain that the IDE port is still working.

The only other thing to check after the system is fixed is to be certain that the third wire ground is continuous from the computer to your main power box. Hope that no one broke a ground pin off to allow use of a two wire extension.

Also, with the UPS off, I'm not sure how the supply got damaged. I assume that the battery had time to get recharged after the power got restored. Some UPS's will not allow the battery to charge when it is turned off. I one that does and one that doesn't.

Have you tried plugging the computer directly into an outlet??

Usually some of the sockets on the UPS are direct from the power line and not actually going throught the UPS circuits. These could confuse the troubleshooting because the straight through ones will certainly work. Maybe hope that UPS failed. Their warranty is wild, because they will pay for damage to the computer but not the UPS itself.

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I'm up and running!
by IAmMelinda / January 19, 2006 8:59 AM PST

It was just the power supply. We took it apart and tested and found power went in but wouldn't come out. It would take a week or more to get the part from HP but they gave me contact info for local authorized repair centers and one had a universal power supply that did fit. I was afraid it might not because, as you said, the parts are jammed in there tight, but it did - lucked out. Have it up and running and it seems fine. I've learned a few lessons about backing up and surge protectors!

Thank you very much for your advice it helped us figure out some of the process.


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Ups Lights
by dsutton9 / January 20, 2006 10:17 AM PST
In reply to: I'm up and running!

One other thing you might want to have checked is the UPS itself it's possible that it is bad also, as it should have prevented any surge reaching you computer power supply.

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I created the problem myself...
by IAmMelinda / January 22, 2006 9:05 AM PST
In reply to: Ups Lights

I was annoyed at the "beeping" from the UPS telling me power was out and I turned it off. I know, I know, twenty lashes with a wet noodle for my stupidity. But, at least I learn from my mistakes and will NEVER turn that off again unless I first unplug the computer entirely from power.

Now if only I could get my laptop to stop dropping its WiFi internet connectivity and all the computers on my network to see each other I'd be a very happy camper. Right now, I'm not! Wink

Thanks again to everyone to all their suggestions and help. It's comforting to know that there are so many people willing to give good advice.

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not booting up
by baskie / March 25, 2008 3:06 AM PDT


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Thank you
by krisdyer / November 28, 2012 3:58 AM PST

Can I say how much of a stud muffin you are? Your solution fixed my problem in 3 minutes. Why did that work? Did you need to drain all the electricity out of it or something?

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Were you still plugged in to the UPS?
by BeelMars / January 24, 2006 2:03 AM PST

If the computer was still plugged into the UPS, it should be protected even if the UPS is turned off. I know you already got the P/S replaced, but many UPSs have a guarantee that will cover electrical damage to anything plugged into them. Check the warranty on your UPS, they may cover the cost of that new P/S

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by IAmMelinda / January 24, 2006 3:14 AM PST was still plugged in. However, the UPS is at least 5, if not more, years old so I don't think I'll pursue that. Thanks for the suggestion and when I replace it, I'll keep it in mind when selecting one. But, from now on, when there's a power outage I intned to totally UNPLUG the computer to protect it. Lesson learned.

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Surge protection:
by funkid7 / March 25, 2008 4:32 AM PDT
In reply to: Yes...

I tend to research my PC and accessories before purchase. This is based on 3 year old research, so it may have improved by now.

Here is the deal on Surge protection itself, the best ones can be useless after three good zaps from the power line surge. The best ones are UL listed and contain up to three capacitors. These capacitors can easily be fried one at a time by 3 large enough surges of hot electricity. The surge has to be higher output, than the capacitors can store and they melt through.

So, it could be possible that a brand new surge protector can become useless after one week of good solid lightning storms.

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power outage no power
by webster4477 / January 6, 2009 12:41 AM PST

had the same problem, it was the power need to replace the power supply box inside the pc...$80 roughly...if you do it yourself you won't have to pay another $50 for someone else to do it.Good Luck,Webster4477

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