Pc fully boots, then turns off

taisamarietaisamarie
edited January 2007 in Hardware
After transfering all our pc components to a new case with new power supply (the old power supply was *just* keeping up), we tried turning on and it powered up beautifully... at least for a few minutes. Got into Windows, everything fully loaded, go to open up the start menu and the pc turns off. After a few more times of this happening, we move everything back to the old case and power supply. Same thing happens. We try the new power supply in the old case, same problem. As a last resort we try booting into safe mode, which it initially does... until the computer does one loud and long beep and turns off again.

I am having a really bad feeling it is the motherboard... does it sound like it? Any other thoughts? Tips?

Comments

  • LeonardoLeonardo Wake up and smell the glaciers Eagle River, Alaska Icrontian
    edited January 2007
    Please check all the fans, including the fan in the back and/or bottom of the power supply. Are they all spinning? This appears to me to be a processor overheating problem. Your motherboard probably has a built-in function to shut down the machine when the processor reaches a threshold temperature. From what you describe, it seems that the time from startup to shutdown is about the same each time, right? That could mean it takes that amount of time for the heat to build up. Gently tug on it and try to push it. If it moves or wiggles, it's probably loose. It's a critical component, as the excess heat generated by the CPU is absorbed by the heatsink and exhausted out of the computer.

    Do you know what the CPU heatsink is? (sorry, I don't know your knowledge level) It's a metal block, usually with a fan mounted on top, that sits on top of the CPU (processor) near the middle-top of the motherboard. It could be that this heatsink was jostled loose during the components transfer.
  • taisamarietaisamarie
    edited January 2007
    All the fans are running, I was thinking it might be the heat sink was loose (as whoever put the motherboard in, in the first place put the board in so tight that it took us an hour to carefully remove it), but didn't think it would overheat in a matter of a minute or two. I'll try some heatsink grease to see if that helps, it would be a lot cheaper than a new board. Thanks :)
  • RyderRyder Kalamazoo, Mi Icrontian
    edited January 2007
    A CPU will overheat in seconds (micro seconds with no heatsink) depending on the contact with the heatsink. It is possible that it was jarred loose during the move or if you didn't get it back on fully if you removed it.

    What type of PSU is the new one? It sounds as if something is shorting and causing he protection circuit to be engaged.

    Most PSU's will respond to a jumpstart which can be performed like this:

    Disconnect the PSU from everything (wall, mobo, etc) ...then plug the unit back into the wall socket and connect a couple hard drives to a molex connector to provide a load.

    Now....with the switch on the back of the PSU in the off position...locate the Dark Green wire in the ATX connector and using a paper clip (or something similar) "jump it" to any of the black wires in the connector....Now flip the switch on the back to On.......the PSU should start up and run.

    Pictures of the jumpstart are here: http://www.bleedinedgesupport.com/ocz/forum/showthread.php?t=5577

    The PSU will run as long as there is sufficient load and the paperclip is inserted, if the PSU runs normally until you shut it off in this manner, you can "semi" rule out the PSU (there are other things that could cause the shutdown when connected to everything) but in general, it should be fine.

    Hope that helps.
  • taisamarietaisamarie
    edited January 2007
    RyderOCZ wrote:
    A CPU will overheat in seconds (micro seconds with no heatsink) depending on the contact with the heatsink. It is possible that it was jarred loose during the move or if you didn't get it back on fully if you removed it.

    What type of PSU is the new one? It sounds as if something is shorting and causing he protection circuit to be engaged.

    The problem happened with both the old and the new power supply, and I brought the new power supply to work this morning to test on another computer and it has no problems. It is a 500w CoolMaster IGreen.

    I am 90% sure at this point it is the heatsink and after work will be making a trip to the parts shop to get some arctic silver. Will let everyone know what happens. Thanks for your advice. :)
  • LeonardoLeonardo Wake up and smell the glaciers Eagle River, Alaska Icrontian
    edited January 2007
    Do you have experience applying thermal paste? Do you know how to apply it properly?
  • taisamarietaisamarie
    edited January 2007
    Yes, after cleaning the old pad of the heatsink very carefully as to not scratch it, put a smal drop about the size of a grain of rice in the center of the heatspreader on the processor. Set the heatsink on, gently twist back and forth to eliminate bubbles, clamp on and (hopefully) happy computing.

    I know a fair amount about computers, its just after a few days of sleep dep everything that happens makes my mind scream worst case scenario. :P
  • taisamarietaisamarie
    edited January 2007
    Won't be able to get the thermal paste until tommorow, but I was just noticing as well that the stand for the heatsink is loose. It is a black, plastic square that the heatsink edges sit in and then a clip holds the heatsink on the stand and cpu... any ideas as to what to use to reattatch the plastic stand to the motherboard?
  • PterocarpousPterocarpous Rosie the Riveter Lives On in CA, USA! New
    edited January 2007
    taisamarie wrote:
    Won't be able to get the thermal paste until tommorow, but I was just noticing as well that the stand for the heatsink is loose. It is a black, plastic square that the heatsink edges sit in and then a clip holds the heatsink on the stand and cpu... any ideas as to what to use to reattatch the plastic stand to the motherboard?
    That's pretty significant. If the heat sink is not seated flush and snug against the processor then it cannot wick the heat off of the processor effeciently. The end result is your processor overheating and causing the system to shut down. Sounds like a new HSA + heat sink compound (thermal paste) is the ticket. :smiles:

    EDIT://
    Re-read your post. This clip assy (assembly) is part of the motherboard not the HSA, right? Are there plastic pins or tabs (coming off this assy) that go thru the motherboard? How is this assy. attached to the mobo? Bottom line is, if it's broken away from the mobo, it has to be repaired or replaced. You might want to check w/ the motherboard manufacturer online. Others here will have suggestions as well. (There may be alternatives if the clip assy cannot be repaired.) Hopefully a simpler resolution. Bottom line is the heat sink must be flush against the processor or you will not be able to adequately cool it.

    PS:
    RyderOCZ, thanx for the link! Great tip for testing PSUs. :)
  • taisamarietaisamarie
    edited January 2007
    The clip on the hsa is just fine, but it is where the assembly attatches to the motherboard (the plastic little pins are lose). One thing I've never had to completely replace is the heatsink assembly... so they typically come with new heatsinks or ?? :P
  • PterocarpousPterocarpous Rosie the Riveter Lives On in CA, USA! New
    edited January 2007
    taisamarie wrote:
    The clip on the hsa is just fine, but it is where the assembly attatches to the motherboard (the plastic little pins are lose). One thing I've never had to completely replace is the heatsink assembly... so they typically come with new heatsinks or ?? :P
    Hmmmm.... I'm not quite clear about exactly what is loose. However, if this affects how tightly the HSA will be able to attach (or be clamped down) against the CPU, then it poses a significant problem.

    To get a clearer understanding of what you are referring to, it would be best if we have a picture of the motherboard. To that end, please, let us know what motherboard you have. If you don't know how to determine this, w/ flashlight in hand, look closely at your motherboad and look for etching or silk screening on the board in the form, usually, of a combination of numbers and letters. Look for a revision number, too. That will usually be near the model number of the board but in much smaller print. Of course, if you find the manufacturer's name there, too - let us know that as well. (e.g. MSI, Asus, etc.) Once we have this information, we'll be able to obtain a picture of the board from the manufacturer (or some other source online).
  • taisamarietaisamarie
    edited January 2007
    The board is a Socket 478 with a P4... this motherboard is very close... http://images.tigerdirect.com/itemDetails/A455-1044/A455-1044-out2-hl.jpg what is loose (loose pins) is the black assembly that normally holds the heat sink that surrounds the chip socket.
  • profdlpprofdlp The Holy City Of Westlake, Ohio
    edited January 2007
    If you take the motherboard out of the case you should be able to tighten the bracket down from the back. :)
  • taisamarietaisamarie
    edited January 2007
    I wish it was that simple, they are these little white pins, not screws, that pop in and out and they are worn so they are loose. :P I think I found a place online though that sells the bracket mount assembly for the board. Only $8 so it is worth a shot. :) Here is to hoping.
  • PterocarpousPterocarpous Rosie the Riveter Lives On in CA, USA! New
    edited January 2007
    taisamarie wrote:
    I wish it was that simple, they are these little white pins, not screws, that pop in and out and they are worn so they are loose. :P I think I found a place online though that sells the bracket mount assembly for the board. Only $8 so it is worth a shot. :) Here is to hoping.
    That's what I was afraid of... Hopefully the bracket will fit properly. Do they include instructions re: how to remove the existing bracket w/out damaging your motherboard??
Sign In or Register to comment.