Power Surge question

Cliff_ForsterCliff_Forster Icrontian
edited August 2011 in Hardware
My in Mother/Father law's PC was the victim of a very nasty power surge. Lots of storm activity around here lately, he lost a Garage door opener, two desktop PC's, a monitor, a printer, it was bloody!

So anyway, I have their main system they use for business. No power at all, so I figure the supply is zapped, but I pull the PSU plug in an optical drive, jump it from green to black with a good ole paperclip and what do ya know, fans spin, drive functions, sooooo......

Is it possible for a surge to completely bypass the power supply not damaging it to zap the board? Will a PSU come out unscathed, should I trust it to power the replacement parts I just ordered?

Comments

  • Straight_ManStraight_Man Geeky, in my own way Naples, FL Icrontian
    edited August 2011
    No.
  • TushonTushon I'm scared, Coach Alexandria, VA Icrontian
    edited August 2011
    I'll wait for someone more informed to answer, but I don't think a PSU would come out of that unscathed.
  • Cliff_ForsterCliff_Forster Icrontian
    edited August 2011
    Straight_Man wrote:
    No.

    No meaning I should probably replace the PSU too?
  • TushonTushon I'm scared, Coach Alexandria, VA Icrontian
    edited August 2011
    Cliff_Forster wrote:
    No meaning I should probably replace the PSU too?

    Yes. ;)
  • Cliff_ForsterCliff_Forster Icrontian
    edited August 2011
    Have you seen the paper clip jumper work without booting a mobo?
  • RootWyrmRootWyrm Icrontian
    edited August 2011
    Cliff_Forster wrote:
    Have you seen the paper clip jumper work without booting a mobo?

    Sure, but you need a toolkit or tester to do it. Many modern ATX PSUs will not start with zero load; depends on the voltage regulation scheme. PSU testers typically have a 1A load resistor in them. You can do it with any 1A resistor, just stuff it between +5V and any GND.

    PSU's definitely toast. Or unsafe. If there was an OCP circuit or fuse in the PSU, surge would have blown it out - that's how it's designed to work. Typically in a surge/strike situation, the PSU will blow the OCP or fuse, sacrificing itself to save some/most attached parts. Given your test scenario, may be that OCP or fuse for +12V or +3.3V is blown.
    I wouldn't waste time doing further diagnosis though; like I said, bad or unsafe. I'd try to get insurance claim for the whole system if possible; even when a PSU sacrifices itself, things sometimes get through. Could be that enough got through to fry VReg on the board, or any other number of things.
  • RyderRyder Kalamazoo, Mi Icrontian
    edited August 2011
    Paperclip jumper without booting a mobo? Sure, works on most PSU's manufactured post 2004/2005.

    If the PSU jumpstarts (I would add an HDD or 2 to a molex, because some PSU's need some load on 12V and 5V lines to provide proper voltages) and you can measure the voltages on the various lines with a DMM, then yes the PSU could be fine.
  • Cliff_ForsterCliff_Forster Icrontian
    edited August 2011
    Lets play, "Whats the worst that can happen?"

    Lets assume the surge did something evil to the supply. If I plug it into a new board, is it possible it could damage it? I suppose that's a fairly dumb question?? Will it simply not work, or could it fail to convert voltage properly and actually zap another mobo?
  • ThraxThrax 🐌 Austin, TX Icrontian
    edited August 2011
    Cliff_Forster wrote:
    If I plug it into a new board, is it possible it could damage it?


    Yes. Possible, even probable.
  • Cliff_ForsterCliff_Forster Icrontian
    edited August 2011
    Oh Darn, suppose I'll buy another PSU while I'm at it. Thanks guys.
  • RootWyrmRootWyrm Icrontian
    edited August 2011
    Thrax wrote:
    Yes. Possible, even probable.

    ^^^
    This.
    Never re-use components subjected to lightning strikes. The only guarantee is that if they haven't failed yet, they will. It's not worth the risk.
  • Cliff_ForsterCliff_Forster Icrontian
    edited August 2011
    I'm going to swap the unit, but I had to, for my curiosity go old school on it, grab the voltmeter and test each and every freaking pin!

    Everything is well within tolerance, in fact, the 3.3 and 12 volt sources are perfect, 5 volt is just over, well within the 5% tolerance.

    Part of me wants to just pop it on the new board for science, but I will resist, maybe at some point when I have a mobo CPU and Ram I consider semi disposable, maybe then I'll give it a whirl.
Sign In or Register to comment.