Grounding problem or something more concerning?

Associate
Joined
2 Sep 2013
Posts
2,297
Hi all. Slightly new issue.

Have been reconfiguring system a lot lately and discovered something very unusual. During certain times, on touching the case, I can feel a tingling sensation in my fingers that are in contact with the case. And when I rub my fingers across the metal parts of the case, it's a bit like rubbing up against a wet/cold window and the fritction that causes (with all the squeaking too). Except it's constant.

From a few tests (listed below), I've narrowed it down to it being caused by the speakers Line In Jack (Logitech X140), so I just want to run this by everyone else to see if I've missed something else blatantly obvious as being an alternative cause of the issue.

Reasons for this conclusion:
1. When the speaker is unplugged and not remotely close to the case, there is no tingling sensation when touching the case or running my hands or fingers across the metal parts of the case.
2. When the speaker is plugged in and plugged into the Line In (Front) of the motherboard, the sensation can't be felt if the PSU cable is also in. So I think this means that Grounding is working properly, as they are both connected to the same Surge Protector and Wall Outlet.
3. When the speaker remains plugged into the motherboard Line In or touching the case, but the PSU is not (Not both connected to same ground), the tingling sensation can be felt again.
4. If I am holding the Line In Jack, and then touch the case, it is fine if I do not touch the actual connection itself (the metal on the Jack). But the moment I touch the metal and then the case, the tingling sensation is back.

So from that, I concluded the Speaker as the actual cause of the issue. Taking it apart, I did notice that on the circuitboard in the speaker, there was a power line and a neutral line, that had solder overlapping the two lines (a power line and neutral/ground), possibly causing the slight buzzing sound, but also the possible issue of sending some current down the Line In Jack (Cable). So I've decided to ditch that set of speakers.

Again, my only question now, is that does anyone see anything wrong with the logic presented here and should I test for any other issues before assuming all is now safe?

Thanks all.
 
Sounds definitely like speakers lack own grounding and use ground of signal wire to ground themselves through PC.
Though at least basing on youtube teardown of X140 they should use transformer and ther shouldn't anything of mains AC leaking through.
(transformer's output is galvanically isolated from mains/earth ground)

If question was about PC lacking ground, then you would feel that tingling always.
 
Thanks for confirming. Will still ditch the speakers though, as on taking it apart, discovered that some engineer used/stripped the head of a screw holding the speaker together. So was further non-plus'd on finding out about that. Will need to go about grabbing a set of speakers for the main rig too then. Thanks again @EsaT :)
 
For music stereo speakers work fine, but if gaming is main use good headphones and binaural sound can give way better immersion.
(also feel of distances in addition to direction)
Without cost and space requirements and room acoustics worries of surround set.
 
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