Can a bad power supply ruin the motherboard ?

Discussion in 'Computer Support' started by Craig, Aug 7, 2005.

  1. Craig

    Craig Guest

    My computer was running fine and I left the room and when I came
    back in it was off. The monitor was on but the computer was off.
    When I tried to turn it back on, nothing happened at all.

    It is an old gateway 300.

    It was rather hot in here, so I waited an hour and tried to turn it
    on again, the power button just for a second lit yellow and then

    I put a new power supply in it and checked everything including the
    plug from the on/off switch, and the same thing happened,
    No power, no fans, nothing.

    Once in a while the on/off button would for a second light yellow.

    If my power supply did go bad, could that have ruined the

    Thank You
    Craig, Aug 7, 2005
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  2. Craig

    Toolman Tim Guest

    Yes. Very easily. Or the other way around: I have several systems at work
    that the motherboard failed, and it fried the PS when it went.
    Toolman Tim, Aug 7, 2005
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  3. Craig

    J-McC Guest

    Unfortunately YES!, a faulty power supply can fry your main board and
    hard disk etc.

    Take note that provided the power supply is ok that the highest
    voltage that will be on the mainboard will be approximately +/- 12
    volts, this will not hurt you but be carefull with any jewelery or
    wedding bands as being metal they could short out something.
    If you have access to a multimeter or DVM use it to check the voltages
    on the main connector to the motherboard, you should get +/- 12v, +/-
    3.0v and possibly some other voltages. If you get anything over 12
    volts then get someon who knows what they are doing to help you.

    If the suppy had really shit itself and put 240v (or 110v) onto your
    main board then you would instantly see a lot of physical damage, bit
    like either being runover by a small car or by a Mack Truck!

    Smell the main board and see if you can detect an epoxy smell. Remove
    the Ram, all cards that are plugged into any ide/pc/ISAi slots. Take
    note of which cards were in which connector so you can put them back
    into the same slots. Feel the tops of all the larger ic's and see if
    you can feel any bumps/imperfections on the tops, if you do then use a
    magnifying glass and carefully inspect the tops, if you see any
    bubbles or blisters then I think the mainboard will be damaged and
    need replacement.

    If you are unsure get someone who is experienced with hardware to
    check for you. If all seems ok then do the following.

    Unplug your Harddrive, cdrom, floppy and just leave the mainboard
    connected to the power supply, and then turn the power on. If the CPU
    fan starts running, good. then put your finger carefully on to the
    top of any ICS (the large black postage stamp size things you can see
    on the mainboard. Just see if any are getting very hot, ie you dont
    want to leave your finger there!, also check the memory and the cards
    that you have removed for any blemishes ontop of any of the inetgrated
    circuits that are on them.

    I have been involved in computer and electronics since 1963 and have
    only seen a handfull of wrecked motherboards due to power supply
    failure. My Daughter had her whole p/c ruined recently and it was
    the fourth time that I had actually seem the chips (ics) on her hard
    drive split open. She had been running the p/c outside on several
    extension leads and one of the mains connectors was loose and when she
    pushed them back together she said she got several sparks and that was
    the end of her computer. When I looked at the memory and the
    mainboard I was able to see little raised bits on a lot of the chips
    on her motherboard, ram, and cards plugged into the pci slots. Every
    item on her computer was wrecked, but this is very rare, and for me
    being her Dad, was a costly experience for me!

    This level of destruction is not common but as I have stated I have
    seen it before. Best of luck!
    J McC.
    J-McC, Aug 7, 2005
  4. Craig

    PC Guest


    If the power supply is ATX, one possibility (though very rare) is the power
    switch has shorted permanently closed, ATX power supplies read this to mean
    you want to shut down again straight away.

    If this is not the case the quickest way to determine the problem is to
    remove all cards, and drives leaving only the CPU, Video card and RAM.
    If still no joy, substitution of parts from your old pc to another is the
    quickest way of testing them.
    If it comes down to the motherboard/CPU I would give it away on economic

    Power supplies can kill motherboards, but usually noticeably so (read smoke,
    I have had some motherboards do what you describe, just stop. In all these
    cases the power supply was not the cause but something on the motherboard
    letting go. What, I have no idea, not worth chasing up.

    PC, Aug 7, 2005
  5. In Craig
    <> first attempted to communicate with pen, but the writing was
    small, so next used sidewalk chalk, but the rain washed it away, and then
    switched to spray paint and stencils but the cans exploded, so placed
    fingers to keyboard for this:
    Oh yes it can! A few years back I had a self-built system with a very nice
    power supply that the builder installed. The power supply had two channels,
    I believe is the correct term, so that you could run your system temporarily
    on one of the channels if something happened to the other. Anyhow,
    unbeknownst to me a spider had gotten into the power supply and found it a
    nice, warm place to live. The spider grew bigger and bigger over the course
    of time and one day when I went to turn the PC on, the power supply fried
    the spider and also the motherboard at the same time. Luckily my HDD was
    fine along with all my information. But the technician did tell me that I
    was lucky it didn't slam the HDD as well.
    Sens Fan Happy In Ohio, Aug 7, 2005
  6. Craig

    Toolman Tim Guest

    Heh! I had a mouse crawl inside a $5000 printer (for real! Thermal transfer
    label machine by Zebra in like 1989 or so) and pee on the main board. Cost
    me $900 to send back for repairs. I made them send me a schematic - next
    time something died, I got the parts and fixed it myself <g>
    Toolman Tim, Aug 7, 2005
  7. Craig

    Craig Guest

    Thanks for all the replies,

    I did disconnect all the drives and still nothing.

    All I ever get is the first time I push the on/off buttone is a
    flicker of yellow light, I doubt that means a thing.

    When this first happened there was a hint of the familiar burning
    component smell and I thought that was the power supply.

    So I would have to guess it is the mother board.

    Just a shot in the dark, but could the battery have a thing to do
    with this, replacing the battery help.

    I wouldnt think so, but then again you never know.

    Craig, Aug 7, 2005
  8. Craig

    Toolman Tim Guest

    Nope. If you smelled the smoke, it's toast.
    Toolman Tim, Aug 7, 2005
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