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Resolved [dead desktop - only power supply LED lights]

Discussion in 'PC Hardware' started by Dave932932, 2011/08/27.

  1. 2011/08/27
    Dave932932

    Dave932932 Inactive Thread Starter

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    This PC won't turn on at all. You push the power button and nothing happens. No CPU fan noise, no hard disk spinning, nothing. The only thing that works on the machine is the power supply LED.

    Power cord is plugged in, yes. Tried a different AC cord.
    Is plugged into working outlet, yes. Verified with lamp.
    Unplugged wifi adapter, leaving only power, PS2 keyboard, USB mouse, VGA monitor, 3.5mm speaker cord.

    The only change that's recently happened was a move of several hundred miles, but I don't see any physical damage.
     
    Dave932932,
    #1
  2. 2011/08/27
    PeteC

    PeteC SuperGeek Staff

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    Working in the dark here without knowing any details of the computer, bit late now, but ....

    Please enter your System Details. It helps us in answering your questions!

    By power supply led do you mean the power led on the motherboard or one on the case?

    Could be that the power button on the case has failed. This can be checked by locating the connections from the power switch at the motherboard (mobo manual) and carefully removing them. Then briefly short the two pins - if the power button is at fault the computer should power up. If it does not the problem lies elsewhere.
     
    PeteC,
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  4. 2011/08/27
    rsinfo

    rsinfo SuperGeek Alumni

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    Also make sure that none of the buttons [power & reset] are jammed.
     
    rsinfo,
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  5. 2011/08/27
    Dave932932

    Dave932932 Inactive Thread Starter

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    The power LED is a green one on the back belonging to the power supply. The motherboard's power LED is on the front. There's three twisted pairs leading to the front, which I believe are for the hard disk activity light, power button LED, and power button switch. The three twisted pairs connect with a 9-pin plug to the motherboard.


    HP Pavilion a255c
    Windows XP SP3
    Intel P4 2.66GHz
    512MB DDR1 (single stick)
    Nvidia Geforce4 MX440
    Seagate 120GB PATA
     
    Dave932932,
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  6. 2011/08/27
    PeteC

    PeteC SuperGeek Staff

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    If that is the case - in my experience of building my own computers there are 9 individual plugs, but I have not owned an OEM computer for 15+ years and OEM's may do things differently.

    The best you can do is to try and identify which leads come from the power switch - this may involve partial dissembly of the case and once you are clear which pins connect to the power switch remove the 9 pin plug and proceed as I posted earlier.

    As rsinfo posts check as far as possible that the power/reset buttons are not sticking. They should return to the null position each time they are pressed and released. As the power button is push on/push off you may detect the noise of the contacts as they make passing contact.
     
    PeteC,
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  7. 2011/08/27
    Whiskeyman Lifetime Subscription

    Whiskeyman Inactive Alumni

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    Sounds like the motherboard has shifted and is shorting against the case. Make sure the screws holding the motherboard to the stand offs are tight.
     
    Whiskeyman,
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  8. 2011/08/30
    Patonb

    Patonb Inactive

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    The movement can do a lot, from shifting the mobo, dislodging a ram stick, or slightly uplugging the 20/24 or 4/8 pin.

    I'd suggest going over all the major plugs to ensure theyre all solid.

    Ads to the 9 "pin" front panel, ASUS use to make a connector that the individual connections would plug into, so you could easily plug everything in, then just stick it onto the mobo.
     
    Patonb,
    #7
  9. 2011/09/09
    Dave932932

    Dave932932 Inactive Thread Starter

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    Well, after tightening a loose mobo *****, unplugging and re-plugging the mobo power plug, I finally tried just shorting the switch. Touched pins 1+2, nothing. Touched 2+3, nothing. Touched 3+4 whirrrrrrrrrrrrrr. It works!

    edit: It appears that the word for fasteners characterized by spiral grooves is blocked.
     
    Last edited: 2011/09/09
    Dave932932,
    #8
  10. 2011/09/09
    rsinfo

    rsinfo SuperGeek Alumni

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    Good work & thanks for the update.

    Please mark your thread as 'Resolved'.

     
    rsinfo,
    #9

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