Thread: PC still shutting off randomly

  1. #1
    Registered User VirtualAce's Avatar
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    PC still shutting off randomly

    I'm still having problems with my PC shutting off randomly. I have wiggled every connection in the machine and have been unable to force it to shut off. However a tap here or there or sometimes closing the front bezel door can cause it to shut off. If it is not a short then what is causing this?

    I have a 1000W Antec PSU and am probably using about 600 according to the ASUS web applet for my mobo. Antec has stated they believe a voltage spike is causing a massive drain on the PSU and it shuts off to protect the system. Whatever. Every component in my system is only about a year old and the video card is only 2 months old. When I built this I replaced all my old components, connections, and cables with new ones.

    I'm completely lost as to what is going on and even moreso how to fix it.
    Last edited by VirtualAce; 12-30-2010 at 10:28 PM.

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    It sounds like a faulty power supply... possibly cold solder or a broken wire.

    I'd try patching in a different supply and see if the problem clears up.

    If not... disconnect/remove the components in your system one by one and see if the shutdowns stop. The missing part will be the bad one.

  3. #3
    Registered User VirtualAce's Avatar
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    Well thats the thing...it doesn't shut off all the time. So I would have to remove a component and leave it our for a long time to see if that was the culprit. Sometimes it hums along just fine and other days it shuts off. A very strange problem. I'm going to investigate the internal case wiring to see if perhaps that is where the issue is. It can't be any of my components. If it is the PSU as I first suspected it has a 5 year warranty on it so I'm good for an RMA. It started doing this about 6 months ago about 6 months after I built the thing. The first time it did it was when I was programming some GPU shaders. I honestly thought my shader code killed the GPU or my other code triple faulted the CPU when it happened.
    Last edited by VirtualAce; 12-30-2010 at 10:49 PM.

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    Master Apprentice phantomotap's Avatar
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    However a tap here or there or sometimes closing the front bezel door can cause it to shut off.
    O_o

    If that's not a variety of short in action, I'll eat my hat.

    I've seen micro fractures in a motherboard cause similar behavior. (The thing was improperly mounted.) It would fail for virtually any reason, but one thing always caused it to fail: slightly jarring the VGA cable.

    If I were you, I'd try to keep a journal of failures. With luck you'll see some consistency to point you in the right direction.

    Soma

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    Quote Originally Posted by Bubba View Post
    Well thats the thing...it doesn't shut off all the time. So I would have to remove a component and leave it our for a long time to see if that was the culprit. Sometimes it hums along just fine and other days it shuts off. A very strange problem. I'm going to investigate the internal case wiring to see if perhaps that is where the issue is. It can't be any of my components. If it is the PSU as I first suspected it has a 5 year warranty on it so I'm good for an RMA. It started doing this about 6 months ago about 6 months after I built the thing. The first time it did it was when I was programming some GPU shaders. I honestly thought my shader code killed the GPU or my other code triple faulted the CPU when it happened.
    Well, your other choice is to unplug clean and reconnect every connector in your machine. Especially the power connectors leading to your motherboard.

    Another possibility... how hot is it running? I've seen a couple of situations where the CPU heatsink isn't seated correctly or doesn't have enough grease on it... things head up under load and poof, thermal shutdown, completely without warning.

    It's not likely to be a short... it's far more likely to be an intermittant open... a connection that is not solid and breaks occasionally. This is easily tested by taking a pair of tweezers and wiggling each of your power leads very gently... If it shuts down, you're probably holding the faulty wire.

  6. #6
    Registered User VirtualAce's Avatar
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    thermal shutdown
    Heat has definitely been on my mind as well. However it can shut off right after I turn it on or 4 hours after I turn it on. If it is heat the first case does not make any sense. ASUS PC Probe shows my CPU temp at 62C under load and 40C to 44C at idle. I would like to keep it under 60C at load but Phenom II's do run a bit on the warm side. I also have a GTX 465 in the case so I'm sure that is increasing the ambient temperature and causing some heat dissipation issues.

    But I will try all of your suggestions fellas b/c I'm completely lost and it is quite annoying. It's like having a short in your car somewhere that annoys you to death but no mechanic can find it when you take it in. I installed the mobo personally and I did not tighten the screws too much so I'm fairly certain the board is ok...although one never knows if ASUS gave me a bad one. My dad has this same board and he RMAed 3 of them before getting one that works. Strangely when he turns his on it also shuts off immediately but then it is fine after resetting and turning it back on.

    This ASUS Crosshair board is quite finicky and I'm really close to scrapping it and moving to an Intel I7 board from ASUS. I can't blame AMD or ASUS for this one but I'm so tired of it I really could care less and am about ready to rebuild the entire thing. I have been building my own systems since the 80386 and I know this is one of those nasty problems that you may never figure out.

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    Expediency may indeed become an issue in any situation... but I wouldn't be in a hurry to trash AMD just yet... I've been using their chips almost exclusively for a long time without troubles.

    There are a few more things to try...

    CMOS Reset ... an old Asus trick, I'd almost forgotten... remove the cmos battery from your motherboard... unplug the computer for half a minute or so... now start it back up, get into the CMOS setup... and while still on, CAREFULLY reinstall the cmos battery. Do your cmos setup and save it...

    Loose Bolts... If you are so sure you did not over-tighten the board mounts... are you sure you didn't under-tighten them? A loose ground will do what you seem to be experiencing.

    Overclocks/Timing... When you do your CMOS Reset... let it auto-detect CPU and Memory timing for a while... see if maybe it's a settings issue.

    Also... for reasons I'm lost to explain... AMD seems more stable on Gigabyte boards than on Asus. So if you're doing a mobo replacement you may want to try GigaByte with your existing hardware.
    Last edited by CommonTater; 12-31-2010 at 11:49 AM.

  8. #8
    Registered User kryptkat's Avatar
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    if it is a thermal issue you should get a temp warning. sometimes you get the warning on reboot.

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    Quote Originally Posted by kryptkat View Post
    if it is a thermal issue you should get a temp warning. sometimes you get the warning on reboot.
    That's going to depend entirely upon software installed in the system. If there's no temperature monitor running in the OS... Nope, no warning.

  10. #10
    Master Apprentice phantomotap's Avatar
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    I would like to keep it under 60C at load but Phenom II's do run a bit on the warm side. I also have a GTX 465 in the case so I'm sure that is increasing the ambient temperature and causing some heat dissipation issues.
    I have a similar setup in one box and have never had a heat problem even though I only tossed in the cheap OEM fans the thing came with.

    I know this is going to sound crazy, but when I was having to verify heat problems on some old (and now gone from the world entirely) kit I... taped up all the exhaust ports and timed timed the shutdown under differently loads. (I traced it to a bad fan. The thing would simply stop under load. I don't know why.) If it doesn't fail under such extreme conditions from heat, it isn't a heat problem.

    My dad has this same board and he RMAed 3 of them before getting one that works. Strangely when he turns his on it also shuts off immediately but then it is fine after resetting and turning it back on.
    I'm guessing that the RAM is not properly paired. Seriously, I've experienced the issue myself on an ASUS board. (I only buy ASUS after having never ending problems with MSI and Gigabyte.) The OEM I ordered the RAM from (as a pair) sent me two single sticks marked with the same specifications. Eventually I tracked it down to the RAM and then the BIOS expectations. (The chips both worked fine when just setup as two single sticks.)

    That's going to depend entirely upon software installed in the system. If there's no temperature monitor running in the OS... Nope, no warning.
    Several BIOS distributions will warn you about such an issue even if the machine has no operating system. As far as I know, absolutely every early Alienware laptop does this.

    Soma

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    Quote Originally Posted by phantomotap View Post
    Several BIOS distributions will warn you about such an issue even if the machine has no operating system. As far as I know, absolutely every early Alienware laptop does this.
    Yes, most laptops have this feature because heat is a significan't problem when you're jamming so much stuff into such a small place... But desktops are a somewhat different realm. There it is assumed you are able to --and will-- provide adequate cooling on your own and very often there is a hardware monitor in the bios but no warning interrupt is issued.

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    Master Apprentice phantomotap's Avatar
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    O_o

    I love the internets.

    Soma

  13. #13
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    I have a similar problem with my computer, except instead of shutting down, it freezes and the video gets all screwed up.
    I'm pretty sure it's because the Intel chip on the motherboard that handles the I/O, Video, Sound, and just about everything else all in one it overheating (when I measured it with an infrared thermometer it was really hot). I tried 2 different ASUS motherboards and 1 Gigabyte motherboard that all have the same Intel chip and they all have that problem in Windows & Linux.
    I finally decided to buy a little fan and power cable (soldered them together) and glued the fan onto the heatsink of the chip.
    It still locks up every once in a while, but not quite as often as before.
    Now I have a frankenstein machine with a loud fan...
    "I am probably the laziest programmer on the planet, a fact with which anyone who has ever seen my code will agree." - esbo, 11/15/2008

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  14. #14
    Registered User kryptkat's Avatar
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    the system the op described asus i believe that they all have the hardware thermister built in.

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    Quote Originally Posted by kryptkat View Post
    the system the op described asus i believe that they all have the hardware thermister built in.
    Yes they do. However the mere presense of the thermistor and the SMBuss do not mean the BIOS is actively monitoring over-temp conditions or will shut down the machine if it overheats.

    Intel CPUs, for example, don't shut down... they slow down until they cool off.

    AMD machines do the opposite, they try to stay cool at all times, running at low speed and staying cool until demand increases.

    You cannot simply shut down a PC, like that...
    Consider the disaster of a desktop system in heavy use for, say, data entry... The operator has been working for hours, there's a ton of pending data, then out of the blue the BIOS pops up with an overheat warning and shuts down the system... How much data --and data is money-- is going to be lost in that instant?

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