Dell Power Supply - lightning strike

Discussion in 'A+ Certification' started by Fred, Jul 5, 2003.

  1. Fred

    Fred Guest

    Hi All,

    I have a Dell 2100 that was the victim of a lightning strike. The main
    symptom so far is the power supply is dead. I disconnected all
    connections to the unit, and tested the supply by itself. There is no
    DC coming out of the supply and the fan inside the supply is not

    If I replace this supply, what do you folks think the odds are that the
    computer will operate? Will the power supply have blocked any damage to
    the PC? I hate to buy one of these non-standard, and expensive power
    supplies, only to find the motherboard is fried too.

    Has anyone had a similar lightning induced failure, and then by
    replacing the supply, had things work OK again?

    Thanks very much,

    Fred, Jul 5, 2003
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  2. Fred

    Ghost Guest

    Sorry.. there is really only one way to find out- do it!

    We keep many PSUs in my shop for test purposes, including proprietary PSUs..
    Ghost, Jul 6, 2003
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  3. Fred

    Fred Guest

    Thanks for all the replies. I actually did have a surge protector on the
    machine... one of those power bar/surge combos. Obviously, it did not do the
    job. Mind you the lightning hit the power wires about 15 feet from my house!

    Looks like I will order the Dell power supply first and see how it goes from
    there. I'll post to let you know how it went.


    Fred, Jul 6, 2003
  4. Careful...I think Dell supplies have a different wiring scheme than a
    standard ATX supply.

    Tom MacIntyre, Jul 7, 2003
  5. Fred

    Fred Guest

    After the lightning strike, there was no DC coming out of the power
    supply. I checked it with my Fluke 77 series Digital VOM. This was with
    the PSU still connected to the motherboard. I opened the power supply,
    and the internal fuse was not blown. The power supply fan was not
    If you put an ATX power supply on a bench, connected to nothing, but
    plugged in to AC, should you not read +5V and +12V at the Molex
    connector? It is my understanding that ATX PSU's (soft power) do not
    turn off, meaning they are always supplying power to the motherboard.
    If not, how would "wake up on LAN" and things like that work?

    Is this correct???
    This is what I was trying to do with the known good power supply, and it
    was killed by connecting it to the motherboard. At least that is what I
    think happened?

    Thanks for the reply.

    Fred, Jul 8, 2003
  6. There should be a +5V standby supply at least. I've never checked an
    ATX supply, but an AT supply will not start without an appropriate
    load, and in typical consumer electronics devices there is only a
    standby supply keeping the uP on when the device is not running.

    It may not be a bad idea to try both supplies with a resistive (dummy)
    load, such as a few smal (automotive may work) bulbs of appropriate
    wattage, so the supply is appropriately loaded, but you don't endanger
    anything expensive.

    Tom MacIntyre, Jul 8, 2003
  7. Fred

    Lee Parsons Guest

    Is there a simple plug-in test instrument for checking power supplies?

    Yes, I can use a multimeter, but it would be nice to have an
    instrument that would automatically check AT and ATX PS's.
    Lee Parsons, Jul 8, 2003
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