Plugging in 4-pin 12V supply causes power to shut off

By htetickrt
Sep 17, 2006
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  1. Hello all,

    I built an Athon 64 3000+ about 2 1/2 years ago, and had no problems; then one day in the middle of an e-mail it up and shuts off on me, refusing to turn back on. I've detached every piece of hardware from the motherboard, including the CPU, with no effect.

    With just the 20-pin power supply connector, the fans run, there is power to the motherboard, and the motherboard lights inform me that the CPU is not posting (as one would expect it not to with no power and now no chip). However, the minute I plug the extra 4 pin 12V supply in to the motherboard, the whole thing shuts off. The 4 pin connector reads 12V when the 20 pin connector is plugged in.

    Any ideas? The MB is an MSI K8T Neo. I didn't jostle it before turning off, I don't think, and a 300W power supply I have leads to the same effect: the fans run with the 20-pin connector in, but as soon as the new PS's 4-pin 12-V supply gets plugged in, everything shuts down (no fans, no MB lights).

    Thanks in advance for any help!
  2. Vigilante

    Vigilante TechSpot Paladin Posts: 2,120

    At the least you must try another power supply. It could be any rail, or a short, that is causing it.
    And if it's not that, I would suspect the CPU or motherboard died.
  3. htetickrt

    htetickrt Newcomer, in training Topic Starter

    Thanks, Vigilante,

    I did try a different, working, PSU, with the same effect.

    Short of owning a spare Mobo with the appropriate socket (754), is there a way to test which of the two (CPU or Mobo) is blown? I don't want to buy a new socket 754 Mobo if the chip might be shot too.
  4. Rik

    Rik Banned Posts: 4,985

    Unfortunately, you need 1 to test the other. You can however visually inspect the mobo, look for domed or leaking capacitors (can shaped components). You can also check for overheating components with a finger.
    That's about all that can be done tho.
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