PC Hardware Gurus... Advice Needed...
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Duncan

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Hi All,

My PC has, this morning developed an unusual fault - maybe you can advise me which way you'd go...

I can turn it on, and passes the POST no problem, and can - at times go in to Windows, and work perfectly normally, but seemingly increasingly - the PC can just randomly shut itself off - Now, everyone may well say its an PSU failure, and I would be inclined to agree apart from one thing...

...The power light of the PC remains lit - even when the power goes off (everything, including the PSU!!), and I have to hold the power button in for three seconds as per normal for ATX to switch it off / on again... so, I'm wondering if this could be a motherboard problem?!

...I can only afford this month, to replace one part, or the other - and I don't really want to be without a fully operational PC for the next three weeks, so - any advice most gratefully received
 
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PsychoZX

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What os are you using?
 
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Duncan

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Win XP SP2 - with all the updates
 
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stevesurf

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Are you letting windows control your power profiles? Go inti the Power Properties and choose "Always On" and make sure that under "advanced" it says "Do Nothing" twice and disable hibernation. That will rule out the hardware switches.
 
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Stephonovich

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Quote:

Originally Posted by stevesurf
Are you letting windows control your power profiles? Go inti the Power Properties and choose "Always On" and make sure that under "advanced" it says "Do Nothing" twice and disable hibernation. That will rule out the hardware switches.


I second that. If it's something else, I'd be more inclined to think it's memory than a PSU, since you mentioned it doesn't always POST. Usually PSU problems are when put under strain, or after having run for awhile. I suggest getting Memtest86 (download the ISO, burn it to a CD) and letting it run for awhile. It'll take quite some time; 8-12 hours isn't out of the question if you have a sizeable amount of RAM, but at least this is free, and will give you an answer on at least one of the possibilities.
 
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Duncan

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Quote:

Originally Posted by stevesurf
Are you letting windows control your power profiles? Go inti the Power Properties and choose "Always On" and make sure that under "advanced" it says "Do Nothing" twice and disable hibernation. That will rule out the hardware switches.


Hiya...

No, nothing has changed in the power profile... same as always...

I find it quite weird that it quite literally 'dies' at random points whilst loading in to Windows (as said in the previous post, which i'm not sure I made clear with Stephanovich's reply - it does go through the POST with no problem)... but that the power light remains on... I wonder if it could be the PSU still, and that the 12v line is shot, but the 5v line (which I would assume would power the 'power' LED) is still good?

I'm genuinly puzzled by this one... I'm at work right now, and have unplugged my PC from the AC whilst here - maybe it'll have sorted itself out, and be business as usual this evening... if not... I don't know.
 
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philodox

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If it is not the PSU or the power settings I would think that it is a motherboard problem unfortunately.
 
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go to Control Panel/Administrative Tools/Even Viewer, then look under application or systems and see if you can find some errors that are causing the problem.
 
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Voodoochile

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Have you tried booting into VGA mode? It's a bit of a stretch, but it might be some wanky driver issues. I'm thinking either that, or heat. Are all the little fans still spinning/not too much dust in there?

Last diagnosis: Has your PC been fraternizing with Rick's? If so, you might need some pennicillin.
 
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rickcr42

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Quote:

Last diagnosis: Has your PC been fraternizing with Rick's? If so, you might need some pennicillin.


Or a sledgehammer
 
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Quote:

Originally Posted by Duncan
Hiya...

No, nothing has changed in the power profile... same as always...

I find it quite weird that it quite literally 'dies' at random points whilst loading in to Windows (as said in the previous post, which i'm not sure I made clear with Stephanovich's reply - it does go through the POST with no problem)... but that the power light remains on... I wonder if it could be the PSU still, and that the 12v line is shot, but the 5v line (which I would assume would power the 'power' LED) is still good?

I'm genuinly puzzled by this one... I'm at work right now, and have unplugged my PC from the AC whilst here - maybe it'll have sorted itself out, and be business as usual this evening... if not... I don't know.



Sounds like failing memory.

If you have more than 1 DIMM remove all but one and try to start the computer. Test each individual DIMM one at a time in the unit until the problems reappear - that's the faulty module. Yes, you can free download MemTest86 but in a multi-DIMM configuration you may have trouble pinning down the exact DIMM based upon the reports.
 
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Duncan

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Hmm... Interesting...

Just got home, and the PC booted up fine first time, is still running now (fingers crossed) BUT.. had to switch out an USB cable, and got zapped by a screw in the back of the case...

Nothing has been touched inside / outside for several months... so, I wonder if it is the PSU - maybe the earth has failed inside (bizarelly the whole case is aluminium, and it is only the screws on the rear fan that shock me - which is right by the PSU...)

The mystery deepens... but, either way, I would envisage it being imminent PSU failure
 
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tkam

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Sounds like a dying PSU but if it isn't I'd check out the RAM as the next likely cause.
 
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Quote:

Originally Posted by tkam
Sounds like a dying PSU but if it isn't I'd check out the RAM as the next likely cause.


I agree. I think its also a PSU problem. My Dell was like this for a while. But I mean it is a Dell...
 
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rickcr42

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Quote:

Nothing has been touched inside / outside for several months... so, I wonder if it is the PSU - maybe the earth has failed inside (bizarelly the whole case is aluminium, and it is only the screws on the rear fan that shock me - which is right by the PSU...)


The reason for the IEC connector is for a safety ground to the case and no way you should have been "zapped" .Leakage current to the chassis points to a short but a dead short would mean fuses blown inernally to protect the computer and blowing a breaker in your home to protect your life so this is a puzzler.


It does sound PSU related but you know where I have just been on the computer power supply front and maybe the "sledgehammer" idea is no as silly as it first looked.totally encased units that really are not very user serviceable.Kinda disposable over fiaxable.

BTW-you may want to just open up the computer with the power off and unplug,inspect,and re-plug all the boards plugged into the motherboard.A common occurrence is bad contact integrity.another part to look at is where these boards actually mount to the panel and check for secure and grounded hardware PLUS plug/jack integrity.I can not count how many times I had a loose parallel port due to unplugging my monitor for one reason or another and instead of just the plugs screws backing out the whole assembly turned and became loose.

POWER OFF FIRST !!!!!!!!!

The internal battery will not harm you but 25 amps or better at +5 volts can !
 
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