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Computer PSU blowout.... help?

Discussion in 'PC hardware help' started by tompsp, Jan 18, 2008.

  1. tompsp

    tompsp Guest

    First of i accept that I was stupid. several times. I would just like to know what I could do to fix it.

    I have built a computer using an iCute atx 500w/p4/ce (thats what it says on the box)

    I put it in, started it up, seemed to be working ok. then the fan started turning off at random intervals, So I tried to figure out what was wrong. I looked at the back and it had a voltage meter. I turned it from 250 volts to 120(or thereabouts). I turn it on, FLASH! a green light comes from my psu. It stopped working.

    ok. I'll just use an old (very old, probably a mistake) psu 350W instead. I put it in, and things start sparking all over the place. LOTS of sparks.

    So.... my question is....

    Is ANYTHING salvageable?
     
  2. sammorris

    sammorris Senior member

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    Potentially. The two PSUs are probably well past it - the icute one certainly is. Putting the old PSU in isn't likely to be the cause of the issues though.

    Unfortunately, installing a new power supply in a PC requires a basic knowledge of electricity. No offense intended here, but that's obviously something you lack.

    A power supply works by taking the electricity from the supply in your house at high voltage (230W for people in the UK, which you probably are, 110/120 for people in the US) and converts it to the low voltage your PC needs (primarily 12V, though 5V, 3.3V and others are also used). It does this by using components which literally divide the electricity supply by 20. 230/20 is roughly equal to 12V. This is what it does if you use the 230V side of the switch.
    Americans of course only need the voltage divided by 10, so when you set the switch to 110V, it divides the 230V of the supply only by 10. As you might imagine, highly sensitive electronics might not be too happy about being given 24V rather than 12V. Anything in your PC that actually received the full blow of this would be demolished, no question. This will also destroy the PSU in good time. What decent power supplies are supposed to do if they detect a faulty circuit (which will have occurred due to components being destroyed) is to shut down the system - of course, if the PSU gets destroyed too, that will happen anyway!
    Using a very old PSU in a system may not always be a good idea, but unless your system draws more than the unit can handle, there's no harm in it. I'm guessing that the sparks that came flying were due to the


    You will need to buy a new power supply plus replace whatever's fried in the PC. You will have to figure that out by unplugging everything and starting in turn - adding components one at a time to see how things progress. As for the PSU, I would recommend not buying a cheap value one. That probably had no hand in what happened to you here, but equal devastation can occur all by itself if you use a cheap "bargain" unit. get a proper PSU like a Corsair unit. The VX450 isn't expensive as power supplies go. (it may well be three times the cost of the iCute unit you bought, but remember, you're buying quality here)

    When you get your new power supply, only plug it into the motherboard - leave the power connectors for everything else (including the 4-pin CPU power connector at the top of the motherboard if you have one) alone, and remove any sticks of RAM there are in your PC.
    All you should have plugged into your motherboard are the fan connectors (fans shouldnt be damaged by this), the connectors that run to the front of the case (USB ports, power switch, power LEDs etc) and the main ATX power connector (20 or 24 pin). Turn the system on like this and see if you hear (or see) any sparks. Don't worry, the new PSU should not be damaged if you do. If you do see/hear trouble, the motherboard is damaged and needs replacing. If that's the case, you'll have to wait until you have a new board before you can test the rest of the system.
    If however, the motherboard sounds OK, plug in your graphics card (if you have one) and test again. Then do the same for the sticks of RAM (do them one at a time if you have more than one) then the hard disks, also one at a time, then plug the CPU back in. Work your way through all the components that take power after that, optical drives, sound cards etc. Eventually you'll get a good idea of what's broken and what isn't and you can replace the parts as necessary.
     
    Last edited: Jan 18, 2008
  3. DedShadow

    DedShadow Regular member

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    Spot on Sam. I think the lesson to be learnt here tompsp is to not turn anything on/off if you dont know what it is. A mate of mine did the exact same thing as you, but his ocnsequences were alot more severe.
     
  4. tompsp

    tompsp Guest

    Thankyou Sam, for a long, and in-depth answer. I am following your advice, and so far, my motherboad seems to be alright. Thanks again :)
     
  5. sammorris

    sammorris Senior member

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    Hehe no worries, any more queries just post again.
    I've not been caught out by the PSU voltage scenario myself, but a friend has, and he had the same experience but without the pretty fireworks. I have indeed experienced a PC go up in smoke (literally) due to a power supply, but this was due to a faulty unit, not my own errors, and it's for this reason that I always advise against cheap units. One day they just decide to go nuts...
     

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