Computer shut down by itself... Any idea why

[Badboy]

Hi,

I was just running AH in offline mode and while I was working on something else, my computer shut itself down. I thought I must have accidentally hit a switch or something, so I turned it back on. It started to power up for just a few seconds before it shut down again. Now the power switch won't turn it on at all.

Power does seem to be getting to the MB, because when I press the power switch to turn on the computer, a small LED on the MB comes on, but that's all that seems to happen. Power supply doesn't seem to come on, none of the fans start up.

Anyone have any idea what the most likely cause for this kind of failure might be?

Badboy

[Skuzzy]

Heat?

[Denholm]

As Skuzzy mentioned, heat. I will go ahead and add in a Power Surge as well.

[Reschke]

Heat would have been my first thought but when you mention that the PSU doesn't want to run up then the possibility of a surge that burned you or the PSU just toasted itself. One other thing did you notice any funny smells coming from the system after the shutdown??

[Fulmar]

My guess is heat or possibly a bad PSU.  And there could be 1000 other reasons why too, motherboard etc.

Open up the side of the case and do a physical inspection.  Use your nose and see if you can detect any burnt plastic smells and also check for scarring.

If you have any spare parts lying around, I'd start with the PSU or use a PSU tester.  Then my next guess would be motherboard if the PSU checks out.

[TilDeath]

Heat would be first... then Power Supply, then MB is toast.  If it were the CPU, Memory or Video card you would get beep codes alerting you to such.  Since no beep code one of the first three

[OOZ662]

If it is the power supply, you may be better off replacing the system. Electricity is funny in that when a PSU dies, it has the habit of taking the rest of the powered components with it. Not always, mind you, but it can be cheaper to just buy a new rig than to go through and replace all the components one-by-one as they cascade through failures due to damage that doesn't show up immediately.

[Chalenge]

Migrating gremlins strike again. 

[Jenks]

Hey Badboy,

It could be heat.....and...it could very well be the PSU.  I just had to replace my PSU because of a similar symptom. The PC would load windows but the shut off after a few minutes.  Or if I tried to load a program or print something.  It gradually got worse for me and shut down sooner and sooner.  Of course I suspected heat early on and cleaned all the dust out and made sure of adequate ventilation. I happened to have a PSU on hand and the problem appears to be solved. 

Whatever you decide to do, best of luck.

Jenks

[Getback]

you can test the heat by using a program. Forget which one but there are several out there.

[TilDeath]

you can test the heat by using a program. Forget which one but there are several out there.

RealTemp will show temps but I don't think he can get there to install and check.  BIOS will show... but not staying on long enough to get there to check.

[TequilaChaser]

depending on your PSU ( Power Supply Unit ), you could have blown a fuse inside of the housing/casing on the PSU curcuit board........ some of the PSU's from mid grade on up have fuses in them....or used to anyhow......

but you did say you had one of your MB lights, light up.........

I have only had a fuse blow one time in one of my PSU's which was quiet a few years ago........(7 or 8 there abouts )

here's to hoping anyways.......

[Badboy]

Guys,

Thanks for the help!

The PSU was dead, it was fairly obvious, it failed the sniff test.

I'm guessing the PSU fan failed without me noticing and eventually that caused the smoke to escape from the wires

I swapped it with one I salvaged from an old system, its only 300 watts and barely man enough, but my AH box is back up and running smoothly until I can replace it with a better one.

Thanks again...

Badboy

[A8Jaraxl]

depending on your PSU ( Power Supply Unit ), you could have blown a fuse inside of the housing/casing on the PSU curcuit board........ some of the PSU's from mid grade on up have fuses in them....or used to anyhow......

but you did say you had one of your MB lights, light up.........

I have only had a fuse blow one time in one of my PSU's which was quiet a few years ago........(7 or 8 there abouts )

here's to hoping anyways.......

Chaser lights on the Motherboard do not really mean anything when looking at a PSU failure. Much like any multi phased transformer, you have differnet parts of the PSU that produce different Voltages. Heat will generally cause the higher voltages to die without always affecting the lower voltages that the MB used for the lights.

To the OP. Ensure you blow your computer (pay close attention to the PSU) out with clean compressed air at least every 3 months or so. Make sure to blow the air in both clockwise and counterclockwise directions over all fans to clean not only the blades but the bearing housings.

The 2 number one reasons for most all computer failures are HEAT and Electrostatic Discharge (ESD) from people touching components without first grounding themselves out.

[Fulmar]

If I had a dime for every time I've encountered a PSU that crapped out because the fan died, I'd have a lot of dimes.