dead motherboard?

By alwyzdreamin04
Dec 31, 2006
  1. So my brothers computer one day just wouldn't turn on at all. Tonight, he swore up and down that it was NOT his motherboard because there was a led light that was working when he tried to turn it on. I took it home with me and plugged it in and everything. It makes no noise, and does aboslutely NOTHING when I try to turn it on. But that ONE led light(on the mobo) does turn on when I hit the power button. I believe the motherboard is dead. I figure, if nothing happens(when powered) except for a light turning on that it means the computer is just getting power and the mobo is dead. Am I right? Is the motherboard dead? And is there a way to test all these parts(I'm in school for computers, just haven't learned how to test things)?
    Thanks guys.
  2. chuck4456

    chuck4456 TS Rookie Posts: 37


    Detailed system specs and POWER SUPPLY ?
  3. alwyzdreamin04

    alwyzdreamin04 TS Rookie Topic Starter

    The power supply is 115V, and specs, I have no clue. Its my brothers computer. I'll have to ask him about them.
    Me and my dad just tested his motherboard battery and the battery has the right voltage, and then we tested the power supply and there is an open circuit. So I think maybe it is the power supply. After we tested his power supply, we tested mine, and mine actually gave off something, instead of an open circuit. They are both 115V. But I'll get the specs from him and let you know.
  4. N3051M

    N3051M TS Evangelist Posts: 2,115

  5. Tmagic650

    Tmagic650 TS Ambassador Posts: 17,244   +234

    Power supplies need to be under load to accurately measure output voltages. This means that the power supply needs to be connected to the motherboard. You can check voltages from the molex connectors on the hard drives or on the CDROM or the ATX (motherboard) connector
  6. alwyzdreamin04

    alwyzdreamin04 TS Rookie Topic Starter


    This is all I could find on the psu.
  7. raybay

    raybay TS Evangelist Posts: 7,241   +9

    You can also use an inexpenisive, but very effective power supply tester available at, or at CompUSA and other computer stores that sell parts and power supplies. It will test all circuits outside the motherboard. It will not test power output, but it will tell you what you need to know for your current task. Cost about $10 to $12 most places.
  8. alwyzdreamin04

    alwyzdreamin04 TS Rookie Topic Starter

    I checked the voltage output through the molex connectors. It said 0. Nothing came up.
  9. Tmagic650

    Tmagic650 TS Ambassador Posts: 17,244   +234

    The molex connectors carry +12v and +5v. It is very unusual to loose both these voltages at the same time. You may have a blown fuse inside the PS. In any case, replace the supply. Please beware, Dell may have used a proprietary supply here. They are not wired like a standard ATX supply
  10. raybay

    raybay TS Evangelist Posts: 7,241   +9

    How was the power supply connected, and what did you use to test for voltage... a multimeter, or other? How did you assure you should have output? It is so easy to get false readings without a test device.
    However the signs and symptoms are typical.
    Can you trade out another power supply.
  11. alwyzdreamin04

    alwyzdreamin04 TS Rookie Topic Starter

    I switched out his power supply with my power supply after checking to make sure they were the same and stuff...and his computer still didn't work. I talked to my brother and he said some dell guy told him if the green light was on that it probably wasn't the motherboard that was dead. I think the dell guy is nuts, because his computer does nothing. The motherboard is the thing that makes it work, if it does nothing, then the motherboard isn't working right?
  12. Tmagic650

    Tmagic650 TS Ambassador Posts: 17,244   +234

    The green light (LED) is a status light. Green means the +5 volts is present. Normally this would mean all is ok, but there are many other things that can be bad...
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