little zaps from case and odd powerup?


I just finished building a pc w/silverstone st-50ef+ 500W psu and coolermaster case (534 centurion IIRC). mb is msi p965 platinum.

I have 3 questions:

1. mb shows a "+" and "-" for case on/off pins but the case connector is unmarked - for the case on/off sw is there a polarity? The only thing the case on/off, hdd and power led wiring has in common is each has 1 white and 1 colored wire; I assumed wh was hot (if it matters).

2. When I hit the case on/off switch and turn the computer on, the cpu and chassis fans spin up then stop, then start running again fulltime - what's going on?

3. I'm getting little zaps from metal parts of the case and also from a pda plugged into the rear mb usb port; the zaps are infrequent and very small like a static electricity zap but they're definitely coming from the case and not a static electricity zap from walking across the floor. AFAICT everything is properly hooked up (except maybe #1 above), I'm plugged into grounded outlets and my other computer hooked up to this outlet has never zapped me.

Can anyone help with these questions? Thank you.
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More about little zaps case powerup
  1. Have you accidentally grounded your Mobo?

    You shouldn't touch the PC again in its present state - a shock could be dangerous, as well as frying the whole thing!

    Rebuild it :?
  2. Thanks both.

    @mpilchfamily, your psu 101 is terrific - thx for all your effort on that.

    I've been using the computer for ~4 days, everything stays cool, no odd behavior (otherwise), no smells, etc. All standoffs are engaged, there's no debris in the case.

    The cpu/chassis fan spin-up/stop after power on strikes me as odd and then when the occasional teensy zap occurred I started wondering if the psu is the problem.

    Reading about the silverstone I got the impression it's a quality unit so is this initial fan spin-up/stop unusual? I haven't built anything in years so thought maybe some newer psus do a quick diag before powering on otherwise I have to start thinking maybe the psu is faulty.
  3. Hmm, don't like the sound of that. When I installed cpu (e6600, stock hsf) I knew all about ppl's problems getting the hsf fully engaged (mine runs 32-36C always so I know it's in right). I also found/watched an Intel video on correct installation of the hsf.

    I put down the mb box, one of the chassis sides on top of that for some support, then put the foam shipped in mb box on that, then the bag mb is pkg'd in on that then the mb on the bag. cpu pkg was fully seated and locked down and I pushed down each corner of hsf until all 4 were fully inserted. msi manual says "tuirn and lock pins" and I inadvertemtly unlocked one but since Intel video said locking pins is unnecessary I reseated that one leg and left the rest alone.

    When I picked up mb it was visibly arched in the area of cpu socket - I was concerned but went ahead and gingerly screwed it to the case standoffs. But the arching was pronounced and still wonder if it had been damaged in some way.

    So do you have any way of guessing if traces inside the mb might've been damaged? Or if my possible problem is related to the stress the hsf installation seemed to inflict on mb? I'm sensitive to these things so didn't just ram the hsf in but it took a lot of force getting the thing seated and now I'm starting to wonder if mb was damaged in the process.
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