Measurable ac current thru case

[haymaker]

I'm building a FIC AZ11-750 TBird system, using an Enlight ATX case, and an older Creative Voodoo Banshee card. It's the first ATX system I've built. The system starts to the BIOS screen, but I'm hesitating on going farther until I figure out why I have AC current through the case, measuring 2 volts (thru me). I've taken great care screwing the mboard down, but it touches the case at the rear parallel & serial ports still. Is that maybe the problem? I hope it's that simple (hope I haven't already zapped something!)

 

[fast_eddie]

All voltages supplied to the mobo are DC; if you are measuring AC voltage (or getting a 'tingle' to the hair on your arm when you brush the chassis) the problem lies further 'upstream' from the mobo or the power supply is passing an AC ripple current ( very doubtful, but possible).

Is the AC power cord plugged into a properly grounded outlet?
If you are plugged into a surge suppressor; is that plugged into a grounded outlet?

 

[haymaker]

It appears to be coming thru the video cable-I unplugged the power supply first, leaving the monitor plugged, rechecked, then unplugging both ends of the monitor finally stopped the current. Oh, yes I stuck the wall outlets with a tester & they're ok. And it's definitely AC current. The monitor wouldn't be supplying AC to the video card, right?? It's got a nice picture.....maybe it's got something to do with Halloween! Thanks.

 

[Shanky]

Hi. If you have any voltage in the case it usually a ground
problem. Try a different power cord and a different outlet.
make sure you have a good ground from the case to the power supply.

 

[Motorheader]

Grounding at the wall is the most likely issue. Had a friend who did some of his own wiring - everything worked fine, but you got a "tingly" feeling when you touched bare metal on the back of the case.

 

[lenjack]

ac current is redundant....it's either ac or alternating current.

 

[haymaker]

Gee thanks guys, I think you're right. I've learned to not rely on my little outlet tester--I put my meter on it & there it is. I've got a ground block with its wire running back to another bldg, then to earth. Wasn't too complicated after all. Thanks again!