4-pin CPU power problem

By megaderp
Dec 1, 2011
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  1. Every time I connect the 4 pin CPU my whole computer won't start up and then when i take it out it starts up but with a red LED near the CPU thingy. Just yesterday everything was working fine and I did the system BIOs settings and then I had to re-plug in my hard-drive because it didn't recognize it. So when i took out the power cable and put it back in into the hard-drive the computer wouldn't start up anymore. I Checked every-single part with another computer and they all work perfectly fine.

    Attached Files:

  2. Leeky

    Leeky TechSpot Evangelist Posts: 4,378   +97

    You need to use both 4 pin connectors and populate all 8 pins on that motherboard connector. If it has 8 pins you use both of the connectors as per the first picture. If it has 4 pins it will be square, and only requires one connected.

    The leads are split to facilitate the fitment of both ATX connector designs.

    If it still doesn't work once connected with both connectors there is something else not right.
  3. megaderp

    megaderp Newcomer, in training Topic Starter

    I did what you said and the mother board had three green lights when I turned on the power supply but it won't even boot. D=
  4. Leeky

    Leeky TechSpot Evangelist Posts: 4,378   +97

    What exactly do you mean by won't even boot?

    Is there any display?
    You getting any beeps?
    Do you see BIOS?

    If you are confident everything is installed correctly, then it might be worth removing it and testing the motherboard on a bench on work surface that isn't conductive to rule out the motherboard earthing as an issue.

    EDIT: Is the power cable from the processor fan connected to a 4 pin power header on the motherboard? I can't make out if its connected to a three pin or four pin connector. If its connected to a three pin header you need to connect it to the four pin one.
  5. megaderp

    megaderp Newcomer, in training Topic Starter

    I don't get any display, no beep and I dont see BIOS but I did manage to set up the BIOS yesterday somehow.

    when i remove the motherboard and put it on a surface (non-conductive) which parts can I put in? for instance like the CPU, VGA, RAM stuff like that
  6. megaderp

    megaderp Newcomer, in training Topic Starter

    okay everything works except for two things: no signal on my computer screen & when I plug in the two 4 pin connectors. When I do plug in the 4pin connectorss the whole computer will start up for barely a split second and shut down but there are still 3 green lights on my motherboard.
  7. megaderp

    megaderp Newcomer, in training Topic Starter

    =[
    if I only have the ram which is 4x4 and the cpu in my p8p67 asus mobo and only the eatx12v and eatxpwr which is the 8 pin and 24 pin power connectors my set-up won't boot
  8. Leeky

    Leeky TechSpot Evangelist Posts: 4,378   +97

    You will need the following:

    1. CPU attached, thermal paste and cooler
    2. Processor cooler fan lead connected to CPU_FAN 4 pin power header
    3. Both 4-pin connectors fitted (it might work with just one, but you have 2, so fit them)
    4. 24-pin ATX connector
    5. Graphics card
    6. SATA data connector connected to hard disk
    7. SATA power connector connected to hard disk
    8. At least one RAM module fitted.
    9. The case power lead connected to the PWR-SW header on the motherboard.
    10. System speaker connected to the speaker header (otherwise your getting no beeps)

    Please take some pictures of the system fully built up showing the whole motherboard. I'll take a look and see if you have missed anything.
  9. megaderp

    megaderp Newcomer, in training Topic Starter



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