So one wall of outlets in my living room create a strange interference. I watch my Netflix on a laptop connected to the tv (old school CRT) via s video cable, and connect the sound to my old school Pioneer stereo system. So if the computer is plugged in to any of the outlets on one wall, I get a buzz in the sound and the video displays black and white with lines in it on the TV. If the laptop is plugged into the outlet four feet away on the other wall, it's fine. The stereo is plugged into the "good" outlet, and the TV is plugged into the "bad" outlet, if that matters. I thought maybe a ground came loose on that series of outlets, so I took a piece of romex and plugged it into the ground of the good outlet and the ground of the bad outlet, with the laptop plugged into the other outlet of the bad outlet, and it made no difference. Any chance the black and white wires got mixed up somewhere in the series, and it's a polarity issue?
You can buy a tester at the local hardware store for a couple of bucks that will show if everything is wired correctly. It's an orange 3 prong plug you plug into the outlet and has 3 LED lights on it. It should tell you if anything is amiss.
Good call. I didn't know such a thing existed. Thanks!
You can buy noise canceling surge protectors.
Is there a large inductive load on the same circuit (or the same side of the bus) in the box?
cwh
SuperDork
1/8/11 4:52 p.m.
I'm not a real electrician, but I play one on TV. Well, CCTV anyway. Sounds like a ground problem to me, camera systems show similar bars when there is a ground loop. Have no idea how to fix it on a 110vac system, but you could check for voltage between the ground sockets on the different sides. Should not be any showing, but I bet you will find some.
Bad ground or a bad (noisy/dirty) connection somewhere in that circuit.
The switching power supply the computer uses is probably creating your noise issues. All the little capacitors and inductors it uses are nasty for higher frequency noise reflecting back on the electrical system. It's a big issue for power distribution systems that contain a lot of server farms and such, all the reflected noise confuses the protective relaying and grid protection equipment.
Might try to borrow a quality UPS from a friend for the computer to see if it helps. Most of them use a regular linear battery charger to charge a DC battery and from there re-convert to AC with an inverter. The DC part acts like a transformer to isolate high frequency stuff on the AC supply. If it works a new power supply for the computer might fix the issue or you may end up needing a UPS of your own.
