Does this sound like the motherboard or power supply?

Discussion in 'OT Technology' started by Oh Its Joe, Jul 18, 2009.

  1. Oh Its Joe

    Oh Its Joe OT Supporter

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    I went to turn on my computer today but only the hard drive, and the fans would turn on. My usb devices wouldn't work, monitor wouldnt work and i noticed my cpu fan not spinning. I checked to see if the cpu fan was blocked but it wasn't.

    I checked all the connections and everything looks to be in order. I plugged my cpu into another CPU fan header and that didn't work. I have an extra fan but it only requires 3 pins and not 4 like a cpu fan. But I plugged it into the cpu fan header and still nothing. It's either the CPU fan isn't working and the mobo notices that and it wont let me boot up or the mobo is shot or the power supply
     
    Last edited: Jul 18, 2009
  2. Doomsday

    Doomsday XXX

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    that'll be my first guess,... some mobos will refuse to boot if it doesn't detect any rpm in the cpu fan. replace it
     
  3. Oh Its Joe

    Oh Its Joe OT Supporter

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    replace the cpu fan or power supply?
     
  4. Oh Its Joe

    Oh Its Joe OT Supporter

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    I just installed a new cpu fan I had lying around but the fan didn't require 4 pins only 3. But I did still try to plug it into the 4pin CPU fan header but it didn't spin.
     
  5. Oh Its Joe

    Oh Its Joe OT Supporter

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    Can you plug a 3pin fan into a 4 pin header?
     
  6. Doomsday

    Doomsday XXX

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    usually its fine but it depends on the mobo/bios
    some will refuse to boot (i believe dell machines does require a 4-pin fan or it won't work)

    the 4th pin is for fan control, without it, the fan will be always on and its at max rpm. but if the bios requires a signal for the 4th pin, it will detect '0' and will not boot.

    btw,... are you sure you plugged it correctly? pins 1, 2, and 3?
    [​IMG]

    if its not the cpu fan, its more likely a dead mobo since the power supply powers up your hdds and case fans
    but of course, i wouldn't rule that out. its easier/cheaper to test/replace a power supply than a motherboard
     
    Last edited: Jul 19, 2009
  7. Oh Its Joe

    Oh Its Joe OT Supporter

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    I know im plugging the pins in correctly. I've unplugged and plugged it back in dozens of times today.

    My computer is custom built but the mobo is GIGABYTE GA-965P-S3
     
  8. Doomsday

    Doomsday XXX

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    3-pin should work on that board,.. try resetting the cmos

    if it still doesn't work,... not much you can do but to try a different psu (or test with a PSU tester) or replace the motherboard
     
  9. chips

    chips ...

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    any beep codes?
     
  10. Oh Its Joe

    Oh Its Joe OT Supporter

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    How do I reset the cmos?

    I do have a 300w power supply in an old HP. I could use that to just check with the barebone essentials.
    No beeps at all.
     
  11. Doomsday

    Doomsday XXX

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    1. make sure pc is off, unplug power cord from outlet

    2. on the motherboard,... two ways to reset cmos:
    a. look for the cmos header (it should be near the cmos battery), short it with a jumper; or
    b. take out the cmos battery (it looks like a clock battery)

    3. press the power button (note that power cord is still unplug) to drain the capacitors

    4. wait for 1 minute, then take out the jumper, or re-install the battery

    5. plug the power cord to the outlet, then power on

    yeah, try the HP's psu
     
  12. silent008

    silent008 New Member

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    I had faced a similar problem after installing a new RAM module. While installing the RAM module, the pressure made the mobo bend to a certain extent.
    (My system won't boot and only the HDD busy light would lit. the power and fans were not working)

    But because of the screws used to hold the mobo in place the mobo remained that way. Because of this paths in the circuit were touching each other. I unscrewed the mobo, lifted it up and then put it back again with the screws. This solved my problem.
     
  13. Oh Its Joe

    Oh Its Joe OT Supporter

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    Well I had to unscrew the mobo to install that CPU cooler I had. After I screwed it back down nothing.
     
  14. Oh Its Joe

    Oh Its Joe OT Supporter

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    resetting the cmos didn't work.

    I tired that psu and all i got was one long beeeeeep and no power. That big strip that pluggs into the mobo had 4 less pins. :dunno:
     
  15. Oh Its Joe

    Oh Its Joe OT Supporter

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    I'll try to buy a psu today. I hope it's that. I dont feel like replacing my motherboard quite yet.
     
  16. Oh Its Joe

    Oh Its Joe OT Supporter

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    Scatch that thing about the extra psu. It won't work. My mobo doesnt have an onboard video and the psu doesn't have the proper wiring to hook my video card up so I won't be able to test it.
     
  17. Oh Its Joe

    Oh Its Joe OT Supporter

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    I bought a new psu today, It seemed to fix the problem with the CPU cooler but i am still getting no video. The psu i had before was 650w and the new one is 550w. I'm pretty sure the graphics card is getting power since the fan is running. Is it possible that the fan can run but still not recieve enough power to fully run?
     
  18. SeeVinceRun

    SeeVinceRun Currently In Prison OT Supporter

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    550 should be plenty. Test the card in another system if possible, run your onboard video and see if that works (if you have it)
     
  19. Oh Its Joe

    Oh Its Joe OT Supporter

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    My motherboard doesn't have on board. :hs:
     

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