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I just built a new PC for a friend. Everything works perfectly in my home but not his.
But when I delivered it and plugged everything in, we were plagued by (I'm assuming) Ground Loop issues. His speakers emit a loud buzz if I simply touch the speaker din/plug (or plug it into the PC), and the PC refuses to boot if I plug in his Ethernet cable (which I'm told can ALSO be a "Ground Loop" issue.)
I'm pretty sure the problems are related.
In trying to diagnose the problem, we've tried a different speaker cable and tried plugging the speakers into another outlet. (I haven't tried to diagnose the Ethernet issue yet.)
His previous computer had no such problem. Same speakers & Ethernet worked just fine in his previous computer before we started unplugging devices under his desk. His new PC (which I built) boots just fine when physically plugged into the Ethernet at my house and experiences no speaker buzz. The new PC isn't the problem.
It seems awfully strange that he would suddenly have this problem out of the blue, and I have no idea how to fix it. Can anyone help?
(PS: I know there are "Ground Loop" filters for the audio, and he could use WiFi for his Internet, but that's not a "fix", those are "workarounds".)
Mugsy
Posted 2019-01-15T14:48:59.107
Reputation: 51
Ethernet is unable to create a ground loop. Both sides are isolated. But this is a consumer electronics troubleshooting question, which has nothing to do with electronics design. Turn off network booting, and you'll probably be fine. – Jeroen3 – 2019-01-15T15:02:56.290
5I would question @Jeroen3 comment, as you can get a ground loop if you're using shielded cables. So just don't use shielded cables. – None – 2019-01-15T15:28:50.437
1Did you use the same mains lead? Has he checked his sockets for ground fault or live/neutral swap? (this is country-dependent) – pjc50 – 2019-01-15T15:51:29.967
run the PC from a UPS on battery power .... do you still get the problems? – jsotola – 2019-01-15T16:29:27.647
@Puffafish such ground loop is not in the signal path though. – Jeroen3 – 2019-01-15T18:50:40.817
Shields will induce large amounts of interference into the internal wires. Plug everything into ONE power-stripe. – None – 2019-01-15T21:01:50.247