[homers54321]

For the past few months, my desktop would turn off by itself and I would not be able to power it up again. However, a day or so later, it would automatically boot up by itself. At that point, I figured it was an overheating problem and had to do with the fan.

That is until a month ago. It turned off by itself again and this time, it did not turn back on again. So for the past month, I have not been able to power it on.

Worst comes to worst, I remove the hard drive and buy another desktop but I would like to salvage my current desktop. Any advice?

 

[earthpeople]

Bad power supply perhaps?
That can cause unexpected shutdowns if it's overheating or damaged. It's also not too uncommon a problem, so I would take a look at that if you haven't already.

 

[allezz]

Quote:

Originally Posted by homers54321 /img/forum/go_quote.gif For the past few months, my desktop would turn off by itself and I would not be able to power it up again. However, a day or so later, it would automatically boot up by itself. At that point, I figured it was an overheating problem and had to do with the fan. That is until a month ago. It turned off by itself again and this time, it did not turn back on again. So for the past month, I have not been able to power it on. Worst comes to worst, I remove the hard drive and buy another desktop but I would like to salvage my current desktop. Any advice?

Lots of things can cause a computer to shut down by itself. CPU overheating(auto shutdown safety feature), video card loose, incorrect ram timings in bios...Actually that usually leads to a bsod, to name a few.

However you saying it turns back on by itself makes me assume there's something wrong with your motherboard or psu. When you say off and on, do you mean sleep mode...Are your computer's power saving features off in your OS and Bios? If you have wake-on-lan bios setting on, something could of been overheating then when adequately cooled down force your computer to auto turn on in an endless loop.

Did you check the case to motherboard cable/pins that give power to the on/reboot case buttons, they might of been loose then finally came undone as they are very thin and flimsy.

 

[homers54321]

Quote:

Originally Posted by squid+ /img/forum/go_quote.gif Bad power supply perhaps? That can cause unexpected shutdowns if it's overheating or damaged. It's also not too uncommon a problem, so I would take a look at that if you haven't already.

I am thinking it is a bad power supply as well. But what causes a bad power supply? I am almost certain this problem arose from overheating/fan problems. FYI, ive had this desktop for about 5-6 years so could it be old age?

Quote:

Originally Posted by allezz /img/forum/go_quote.gif However you saying it turns back on by itself makes me assume there's something wrong with your motherboard or psu. When you say off and on, do you mean sleep mode...Are your computer's power saving features off in your OS and Bios? If you have wake-on-lan bios setting on, something could of been overheating then when adequately cooled down force your computer to auto turn on in an endless loop.

I am pretty sure its not in sleep mode and I have not tampered with any of the settings.

 

[allezz]

Power supplies usually don't just go on you if they lasted that long, unless the fan dies and you don't notice leaving it fanless for a long time, even then they don't get that hot you can run lower wattage ones fanless. Was it a good brand psu or some crap that came with your case?

What happens when you press the power button on your computer, do the fans start or is it completly dead silent and nothing?

Have the case side panel off while doing this, if nothing happens at all when you push the power button; first thing I would do is check to make sure the case to mobo power pins are on correctly and not loose...Here's a picture of what I'm talking about:

http://farm2.static.flickr.com/1096/...8a636535_o.jpg
into
http://img.hexus.net/v2/motherboards...KDA3+/Pins.jpg

It's bottom right corner basically, check your manual if you don't know what I'm talking about.

If that's not the problem and no fans come on at all anywhere in the case then you most likely have a dead psu or fried motherboard. Do you have a psu from an old computer you could try?

 

[homers54321]

I will definitely try what you suggested tomorrow (it is late in NY). When I press the power button, I hear nothing and it does nothing. Is there a way to tell if it is either the motherboard or the psu without having to go to a computer repair shop? I do not have a spare psu lying around.

 

[eightbitpotion]

It could be a few things-

1. You have an alarm on your computer for whatever temperature, and it's not getting enough air and it's triggering the alarm when your pc, room, or house gets hot which would shut it down. Check the bios setting for the alarm if this may be the case.

2. Your PSU is going out or it may be filthy, simply examine it...clean it if needed, and check for 'odd' smells when it's turned on. A PCB smell is normal, but if you smell anything that is similar to a curling iron or hairdryer smell...it's possibly bad.

3. If you've upgraded any components recently, you may not have enough juice from the PSU... and a CD rom or something will spool up and trip the reset.

All in all, I'd just check your alarm settings...all else seems unlikely to be honest, unless it's just a very crappy psu.

 

[olblueyez]

Clean the crap out of it and if that doesnt work then I say motherboard. I would also replace the bios battery if you have not tried that yet.

You MB is the on/off switch. If your computer stops for any reason it may be set to "restart upon error" or something like that. Scenario: Computer dies for whatever reason, bios battery is drained so it stays off. The battery gets a chance to rest, the bios becomes active for a moment and it restarts. I would not think the battery would cause it to fail when powered on but if it does then this cycle would repeat, but, how many times? Once or twice before the battery is completely dead?

 

[eightbitpotion]

Quote:

Originally Posted by homers54321 /img/forum/go_quote.gif I will definitely try what you suggested tomorrow (it is late in NY). When I press the power button, I hear nothing and it does nothing. Is there a way to tell if it is either the motherboard or the psu without having to go to a computer repair shop? I do not have a spare psu lying around.

This is a sign of a few things, I'd first test the PSU by unplugging everything and bending a paperclip into a "U" and sticking it into the GREEN and any black wire on the main mobo connector....see if it starts up without anything hooked up to it.

If it boots up, try swapping your RAM sticks around as this will almost definitely be the cause.

PS. Unplug the psu when you insert the paperclip first...then plug it back in...

 

[olblueyez]

Its not your power supply, if it were then the computer would not have restarted the second time. Very unlikely, especially if you dont smell anything burnt.

 

[allezz]

Quote:

Originally Posted by eightbitpotion /img/forum/go_quote.gif This is a sign of a few things, I'd first test the PSU by unplugging everything and bending a paperclip into a "U" and sticking it into the GREEN and any black wire on the main mobo connector....see if it starts up without anything hooked up to it. If it boots up, try swapping your RAM sticks around as this will almost definitely be the cause. PS. Unplug the psu when you insert the paperclip first...then plug it back in...

Yeah that's a good way to tell, he probably won't know what you are talking about though as you were rather vague.

Here's a pic Connect! or do a Google search for turning on a PSU without a computer.

 

[homers54321]

So I opened up my tower today and there were no loose plugs and surprisingly, the PSU did not have much dust in it. The fan didn't either as I cleaned it out about a month ago.

One thing that I noticed though is, when I plugged the power supply cable to the PSU, a green light on the back of the PSU turned green. However, when I pressed the power button, that green light goes off. So, I unplugged the cable and then replugged it so the light turned green. Again, when I press the power button, the green light disappears instantly.

Is this significant?

 

[olblueyez]

How bout a 3 dollar battery and then go from there.

 

[CDBacklash]

It does sound like a PSU problem to me. Perhaps it has degraded and can no longer adequately power your components so the computer turns off once the capacitor is depleted?

 

[Uncle Erik]

Sounds like a bad power supply to me. The MTBF on your filter caps is probably due around five or six years of daily use - they might be passing some AC. I'd pick up a PSU from a junk or surplus computer store for a few bucks and swap it to see if that's the cause.