PC turning itself off randomly

Shurakai

Ever since I moved into my new Dorm, my PC has been shutting off at random intervals. It was perfectly fine before I moved.

When I say random, I mean pretty random.

It shuts off after 2 weeks, or right when you press the power button to turn it back on, or 15 minutes after you start everything up. Sometimes it refuses to respond at all (its easy to tell, because my PC has a ton of LED's on it. They dont even light up when it doesn't respond).

At first I thought it might be the power grid. It seemed to shut off at peak times and for all I know my dorm might have the shittiest wiring ever and my power hog of a PC didn't like it. Now thats its been happening longer it seems it doesnt matter if its peak times or not.

Another theory is obviously something got jostled in the move. It was pretty securely fashioned in the vehicle so I doubt this would have done anything but who knows. I checked the inside of the comp and nothing seems out of place.

Another thing that I thought Might effect it was that one of my fans (a side fan) is making a groaning, grating noise and perhaps it is taking too much power to run, causing it just to shut off for safety purposes. I actually hope its that simple, because then all I have to do is unplug or fix the fan somehow. Anyway, any thoughts?

I really am just guessing here, and I'd like to be able to fix it myself without having to take it in to someone as they charge buttloads.

Shurakai

Also, there is a "mystery dial" on the back of my PC right by the Power Supply, that I believe controls the power supply fan. Previously, it was right in the middle of two extremes. It has no label of what is higher or lower, so I tried cranking it to one extreme to see what happened.

My PC is a tad louder, so it seems the fan speed has increased. Could the Power supply have been overheating?

mspencer

Have you had enough time to determine if changing that dial setting improved anything?

Fans in a PC generally consume a nearly fixed amount of power, even when defective. Old brush motors definitely did not -- when they were stalled they would consume a MASSIVE amount of current compared with normal operation.

If the motor is in good working order, that fixed amount of power will turn the fan blades at a decent speed, and all is well.

If the motor is failing, it will start making more noise and the fan blades will be a bit harder to turn, physically -- but the motor is applying the same torque so the fan still spins, but slower.

If the motor is getting closer to completely failing, a stopped fan might require more torque to start than the motor can output -- so the fan will appear stalled, but if you push on a fan blade with your finger that will start the fan back up, slowly.

Finally when the bearing in the motor has gone completely bad, the fan will require more torque to turn than the motor can exert, so the fan won't turn any more. It's still using nearly the same power, but it isn't spinning.

Bad fans aren't a good thing -- they were put there to cool something that needs it, and since PC manufacturers tend to be very cheap, every fan in a machine is probably necessary for stability because if it wasn't necessary it would have been omitted. But bad fans won't kill your PC instantly.

Bad or dirty utility power can cause frequent lockups, absolutely. I'm no expert on fixing this problem, but this guy might be.

(I just wish I could get ahold of one of those ferroresonant power conditioners he talks about. The idea of using pure old-fashioned heavy iron and transformers and physics to handle power surges and dips appeals to me, and I hear they make a cool sound when they're powered up.)

I also like this page of his, titled "How To Destroy Your Computer," which sarcastically describes many things you should avoid doing while attempting to fix your machine.

Also, once you find the problem and get everything square again, his article on fan maintenance might help.

Shurakai

The PC failed again shortly after my last post, so it didnt seem to do anything.

I have considered getting a power filter but I wanted to be sure that was what was causing the problem.

The fan that is slowing down is an unneccesary fan, just part of my case. It blows air onto my cpu heatsink, but the heatsink does a good job by itself.

st0ned messiah

If you can get your hands on a UPS plug it in and see if the problem is inside your computer or inside your walls.

Moridin

Shamelessly stolen from: http://www.microsoft.com/windowsxp/using/helpandsupport/learnmore/russel_02may13.mspx

1. Right-click My Computer, and then click Properties.

2. Click the Advanced tab.

3. Under Startup and Recovery, click Settings to open the Startup and Recovery dialog box.

4. Clear the Automatically restart check box, and click OK the necessary number of times.

5. Restart your computer for the settings to take effect.


I know your computer isn't restarting--its just turning off, but I had a similar problem and this caused the computer to throw a blue screen when it decided to randomly shut off. This should at least point you in the right direction of the error that you're having.

nexuscrawler

If it was a power issue the computer would tend to reboot rather than shutdown totally.After the next crash reboot and go into your BIOS and see what the temps on your mobo and CPU are. If you have struggling fans it may be overheating. Most modern comps have auto shutdown features to prevent damage to components when they're overheating.

TheBurritoMan

nexuscrawler wrote:

If it was a power issue the computer would tend to reboot rather than shutdown totally.After the next crash reboot and go into your BIOS and see what the temps on your mobo and CPU are. If you have struggling fans it may be overheating. Most modern comps have auto shutdown features to prevent damage to components when they're overheating.

It depends on the power issue weather it would reboot or turn off. It is a good idea to check for overheating first, although I don't think that's the issue as the OP has said it's been completely random, sometimes even during startup, when the CPU shouldn't be anywhere near hot enough to trigger such an occurance. But yes, do this first.

What it reall sounds like is a bad PSU. The side fan, is it connected to the PSU or the Mobo? It dying may just be a symptom of a failing power supply.
Things to try:
Plug your computer into a UPS or Line conditioner and see if it continues: If it fixes the problem, The problem likely lies within your home wiring.
If it doesn't fix it
Unplug all of your PSU cables from their components, clean with compressed air, reattach. If this fixes your problem something likely got jostled in the move.
If it doesn't fix it
Pull out your PSU, and buy a new one that's equally or better rated. Plug it in. If this fixes your problem, your PSU went bad. It could have overheated, or just have been a cheap PSU.
If it doesn't fix it
It could be a variety of other things, overheating, short, dust, mobo, et cetera!

FyreWulff

does it have an AMD processor? AMD processors, from my experience, tend to shut down the entire computer when they overheat.

the muffin

Something like this happend to me, what I did was I set a hairdryer to cold and blew away all the dust in the system, then I removed the heatsink on th CPU, dusted it off and then put a little extra glue on the cpu, the part that touches the heatsink, dunno what kind of glue it is though sorry, anyways try that.

Grimm

the muffin wrote:

Something like this happend to me, what I did was I set a hairdryer to cold and blew away all the dust in the system, then I removed the heatsink on th CPU, dusted it off and then put a little extra glue on the cpu, the part that touches the heatsink, dunno what kind of glue it is though sorry, anyways try that.

You mean thermal paste?

redx

uh... everything I've heard about thermal paste, pretty much less is more.

you want some, but really just enough to make a good connection and maximise the contact area. having more than a thin layer, is just going to have it act like in insulator.

cleaning off the old stuff, and putting a wee little bit, isn't a horbile idea, but just throwing some more on, isn't really going to help much.

Shurakai

The CPU isnt overheating, I have temp monitors and such to tell me such things, but the system may be dusty so I guess I have to clean it.

I didn't build my computer myself, unfortunately. Its a custom job but at the time I didnt feel comfortable doing it myself, so I am not sure what is exactly hooked up where. I followed the wiring however and it seems to go into the PSU, though I'm not certain.