PC Hardware forum


PC won't power off, won't power on - for awhile

by fredvirginia / May 13, 2011 10:18 PM PDT

I have a 9 1/2 year-old PC which will sometimes stop working when I'm using it. Let me define "stop working" - the monitor goes black, and I can verify that programs running on the PC have crashed. Yet the lights on the PC remain on. If I try to turn the PC off using the push-button switch, nothing happens. The only way I can turn off the PC is to unplug it. Then, if I try to power the PC on, it will not do anything - for about a day or so. Then it will start up.

The interval between the PC crashing and the time I can turn it on next makes me think of a capacitor that needs time to discharge, but that's just pure speculation.

The most recent time the PC stopped working, it had been running all night with a light load, but crashed when I was browsing internet pages.

So, is this likely to be a bad power supply problem or a bad motherboard problem?

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All Answers

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Or it's old parts?
by R. Proffitt Forum moderator / May 14, 2011 2:29 AM PDT

For example Electrolytic Capacitors are found in old (and new) machines that need replacing. Have you inspected yours?

And then we have heat sink compound. Have you replaced such and while doing so cleaned the machine?

BEWARE those older Socket A machines. Savvy repair shops will reject those at the service counter.

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What I've done
by fredvirginia / May 14, 2011 2:59 AM PDT
In reply to: Or it's old parts?

I have not inspected the capacitors - are you talking about a visual inspection?

This problem first happened awhile back, before a hard drive failure. Recently, I got the machine up and running again by putting in another hard drive and installing Windows XP. I also installed used RAM, a used but faster CPU, and a heat sink/fan, with new thermal paste between the heat sink and CPU. While working on the machine, I vacuumed out as much dust as I could. I did not use compressed air on it. I think in general, it seems relatively clean inside, but there could be some dust in nooks and crannies.

Yes, this is a socket A (462) motherboard from ECS.

Thanks for the reply.

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WAG here
by Willy / May 14, 2011 6:13 AM PDT
In reply to: What I've done

On an old PC, wear&tear can effect anything to include the whole PC in general. I mean, the combo of it all puts strain that finally gives up the ghost. Probably known if it appears to happen after a certain time. I would replace the PSU with similar or better wattage just to cover that side. Everything else becomes suspect due to age if they are of the same period. What happens is th weakest link will cave and that could be anything. As for "bad caps" google for examples of what to look for. It needn't be an extreme bad cap, but a slightly "bugled one" is a failure and at times whole rows are bad. Also, if your system was build at a time when the "voltage regulator pcb" a minor area of the mtrbd. can fail and causes iffy operation. You mentioned you've cleaned, be sure to check the frt. panel area(many are removable) and clean there as a dust blanket is hidden and blocks the "airflow intake" and causes heat stress to include all components inside the PC.

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by R. Proffitt Forum moderator / May 14, 2011 8:37 AM PDT
In reply to: WAG here

After years of dealing with the BAD CAPS plague my inspection is such that nothing but PERFECTION is accepted on the inspection. This is after dealing with far too many machines and a few of the folk telling me "it doesn't look too bad."

If it has even the slightest dome, blown bottom, tilter, leak of any kind, bulge, corrosion or "looks funny" we know to replace it if they will pay the bill.

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by fredvirginia / May 14, 2011 10:05 AM PDT
In reply to: WAG AMPLIFIED.

I opened up the case and examined the capacitors on the motherboard. I couldn't find any that had any bulge on the top, nor did I see any electrolyte leakage. A handful were leaning a small amount.

IF replacing those leaning capacitors requires soldering (I'm assuming they would, but couldn't verify from my vantage point), I probably won't have time in the foreseeable future to take that on. So trying to replace the power supply seems like a better option at this moment to me.

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About "tilters". The inspection is a little harder as you
by R. Proffitt Forum moderator / May 14, 2011 10:29 AM PDT
In reply to: Inspection

It's alright if they don't stand up straight if the bottom is fully intact.

Here's a bad tilter -> http://sites.google.com/site/jimwarholic/Rubycon-MCZ-Bad-Capacitors.gif

See the bottom of the cap on the bottom of the picture. The rubber is distended and can cause that cap to tilt when it should be standing up straight.

Tilting is just a sign to inspect the bottom of the cap.

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Dead horse, don't beat it
by Willy / May 14, 2011 3:00 PM PDT
In reply to: Inspection

Here's a problem with "bad caps" they can also "dry out". A common problem for older caps. They look good and all but lost much of its working value. The tilter Bob offered, notice it isn't much. Once, you find one, its likely others are also. Thus, a decent shop will replace many or a series in order to be safe in the repair. A good scope to test works too. Hint: I use a mag. glass to better view some items nowadays and put light on the subject. Understand that the PSU is hiding alot from view too, that's why I just replace(swap) them out when I test bed a mtrbd.. I have found more "iffy" PSUs than I care to and fixing is not an option, replacement is the cure. Parting shot, "don't take anything for granted". -----Willy Happy

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"electrolytics fail with age by drying out or leaking"
by R. Proffitt Forum moderator / May 15, 2011 1:51 AM PDT

"electrolytics fail with
age by drying out or leaking electrolyte following internal corrosion"

Google that. At nearly 10 years on what we think is a 5 year design you are looking at replacing something.

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Will try the Power Supply
by fredvirginia / May 16, 2011 12:10 PM PDT

I decided to gamble a little money on a new power supply. We'll see if that helps.

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Power supply installed
by fredvirginia / May 24, 2011 11:56 AM PDT

Just wanted to give an update - I installed a new Rosewill 350W power supply on Thursday evening, and have been using the computer since then without any sign of problems.

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Rosewill brand
by Willy / May 25, 2011 12:45 AM PDT
In reply to: Power supply installed

FYI- The Rosewill brand isn't top end. They're a low price brand, so take that into consideration, net time. Wink I realize saving some $ is worthy cause, but it can bite ya. AND yes, I have used them, which is why I know some end results. Sad adios -----Willy Cool

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Why I went with this model
by fredvirginia / June 1, 2011 12:09 PM PDT
In reply to: Rosewill brand

Well, taking into consideration that this was a 9 1/2 year-old computer, I didn't think it wise to spend the money required to get a top end power supply. But there were cheaper models that seemed to be more susceptible to voltage spikes and had scarier reviews than the Rosewill model and I stayed away from them.

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Enjoy and don't fret much.
by R. Proffitt Forum moderator / May 25, 2011 2:13 AM PDT
In reply to: Power supply installed

It's working and since it's one of those Socket A machines, enjoy and don't fret about the rosewill line. At least you avoided the shop counter.

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