Sudden Power off for no reason

By themaxster · 20 replies
Feb 16, 2007
  1. I have recently upgraded my motherboard, fan and processor as my last one broke, some how all the pins were bust. My new spec is shown in the picture on the right:[​IMG]

    Only trouble is when i was running my HP printer install it seemed to be installing and then when i came back to my pc it had gone off completely. I thought maybe it had shut down and not restarted after the install until its been doing it a few times not only when im installign things but just randomly, it doesnt run a shutdown it just goes off like ive pulled the plug, ive tried different sockets etc, and i am just not sure if it is liek i have read on other forums do i need to replace my power supply, i am not experienced with any of this, please help.

  2. beef_jerky4104

    beef_jerky4104 Banned Posts: 822

    I think it is the power supply. If you used the one that came with your case than that is probably the issue.

    Try to replace it.
  3. themaxster

    themaxster TS Rookie Topic Starter


    any specific one i need to get for this type of board and processor?

  4. themaxster

    themaxster TS Rookie Topic Starter

    If Anyone Reads This Please Help Me Out, I Need My Pc For Coursework Asap.
    Thanks :)
  5. beef_jerky4104

    beef_jerky4104 Banned Posts: 822

  6. damienb

    damienb TS Rookie Posts: 55

    What about the RAM??

    Hey there,

    You said you upgraded the mobo, fan and CPU, but what about the RAM?? If you are still using the original RAM, do you know that it is 100% compatible with your new mobo???

    Installing software uses quite a bit of RAM and if its used itensively with a mobo that isn't 100% compatible then it could cause it to fail and shutdown instantly.

    Although I would say that there is a 95% chance of it being your PSU, you should really make sure the RAM is compatible with the mobo first.

    I would recommend a 600W Zalman.
  7. KingCody

    KingCody TS Evangelist Posts: 992   +8

    1. first off, CPU pins don't just randomly bend on their own. it is always the result of human error. why did you replace your motherboard and fan because of "busted" CPU pins?

    2. RAM errors will usually crash the computer, resulting in a BSOD/reboot, not a random shutdown.

    3. there are a few reasons why your system may shut off without warning.

    • overheating

    • motherboard short circuiting (being grounded where it shouldn't)

    • cheap, underpowered power supply

    3a. I would check your temps first, Athlon64 max temp is 65°C (although your motherboard may be set to shut down at a lower temp, check your BIOS for temps and shutdown thresholds). if your heatsink was improperly installed, then your CPU will overheat very easily. did you install it yourself? and if so, did you use any thermal compound between the CPU and heatsink? did you apply it per the manufacturer's instructions?

    3b. if your temps check out fine , then verify that nothing is causing a short circuit. when changing the motherboard, you may have left a metal standoff where there is no mounting hole (which will ground whatever it touches on the back of the mobo). a loose screw behind the mobo could also cause a short. the only way to rule out a short circuit is to remove the motherboard from the case and "table test" it on a non conductive surface (like a piece of cardboard). while the board is out, double check to make sure that there are only standoffs where there is a corresponding mounting hole on the motherboard.

    3c. if [3a] and [3b] are ok, then look towards a bad PSU as the culprit. you should look for a quality PSU by a known reputable brand such as PCP&C, SeaSonic, Corsair, Antec, Enermax, or Fortron. (the latter offers decent quailty high-power PSU models at very affordable prices). use a PSU calculator to find out your system's needs and get a PSU rated higher. watts don't matter, pay close attention to the +12V amperage rating.

    for a mid-range system, a single rail PSU should have 25AMPS or more, a dual/triple/etc rail PSU should have a max combined rating of 25AMPS or more (you cannot simply add the rails together, look at the PSU's specs to find the combined rail maximum)

    for a high-end system (high end video card), you should shoot for a minimum of 30AMPS

    cheers :wave:
  8. themaxster

    themaxster TS Rookie Topic Starter

    Finding a PSU

    my current PSU is 250w

    maybe this is not enough, by your information.
    thank you for your help, but i require further help lookign for a PSU unit.

    is a 400w ATX AMD supported 24 pin super queit and super cool technology PSU any good?

    As i have one here which is exactly that.

    My mobo is : FOXCONN 761GXK8MB - RSH MicroATX M/B

    SKT 939.

  9. kitty500cat

    kitty500cat TS Evangelist Posts: 2,154   +6

    What brand is that power supply? You should probably get only brands that KingCody mentioned. Something like this should be good.

    Regards :)
  10. KingCody

    KingCody TS Evangelist Posts: 992   +8

    themaxster, it sounds like you are looking at a generic PSU. I can't stress enough how important a quality PSU is for the safe and stable operation of your PC (especially since you just bought new components ;))

    modern computers need alot from the +12v rail and very little from the +3.3v and +5v rails. the total PSU wattage is calculated based on all output rails and can be misleading when trying to determine a PSU's actual usable power output. that is why I say watts don't matter. the +3.3, +5, +5SB, and -12 rails will pretty much always have enough power, but cheap PSUs will not have sufficient power on the +12v rail.

    kittycat linked a good PSU. at $40 it's affordable and it provides a combined 25A on the +12 rail. (300w). if you're really strapped for cash then you could get away with this one for under $30. the specs are almost the same, but it's not as "pretty" and it will be louder.

  11. themaxster

    themaxster TS Rookie Topic Starter

    Okay welll on all the power calculators tehre tellign me i need around 300w, but you reckon that i need around 400w? i dont want to dodamamge by putting to much power onto it, if that damages it. I dont know what the rating on my current rail is all i know is that its 250w.

    Thanks Again.

  12. kitty500cat

    kitty500cat TS Evangelist Posts: 2,154   +6

    No, it won't damage it.

    A power supply will only give your system what it needs. So if your system only needs 300w, the power consumption will only be at 300w (assuming 100% efficiency). 400w is just the maximum amount that PSU can give.

    Regards :)
  13. themaxster

    themaxster TS Rookie Topic Starter

    Thanks kitty500cat, I have checked my settings before the PC boots up in the CMOS and the settings where it says the shutdown thresholds and all the temperatures are set but it says Disabled, could this be anything to do with it?

    Thank you to everyone for your help.

  14. KingCody

    KingCody TS Evangelist Posts: 992   +8

    the fact that the temp shutdown threshold is set to "disabled" rules out overheating as the cause. it is now pretty much certain that your PSU is to blame...

    250w is not enough for most modern systems. since you have that 400w PSU already, you should use that one instead. chances are it will fix your problem right away ;)
  15. themaxster

    themaxster TS Rookie Topic Starter

    KingCody and all others

    Thank you for your help, i shall try that out and let you know how i get on.

    You are all a great help and id just like to thank you for your advice and help.

  16. themaxster

    themaxster TS Rookie Topic Starter

    New PSU 400w And Extra RAM 512MB, All sorted and fine, thanks for all your help.


  17. KingCody

    KingCody TS Evangelist Posts: 992   +8

    glad to hear you got it working :)

    cheers :wave:
  18. beef_jerky4104

    beef_jerky4104 Banned Posts: 822

    Knew it was the power supply.
  19. themaxster

    themaxster TS Rookie Topic Starter

    OR MAYBE ITS NOT :mad:

    I installed my printer which is really demanding for teh pc and it shut down again :( this is after i added another 512mb memory and with a new psu. any othe sugegstions?

  20. Jakovasaur

    Jakovasaur TS Rookie

    Possibly the new mother board as long as this PSU is doing ok, I'd be suspicious of the MB
  21. themaxster

    themaxster TS Rookie Topic Starter

    Thanks mate , i will try a different one and see what happens, ill let you know.

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