I have a new LG 32 inch plasma EDTV, and I'm getting whiteish grey horizontal bars scrolling up the screen from the bottom to the top, repeatedly. I have searched this forum and this appears to be the standard "ground loop" issue described elsewhere. There are a couple of odd inconsistencies though, and I'm looking for some advice.
My TV is plugged into a 3-prong outlet and thus grounded there. My digital Cable Box and my DVR are also plugged into the same outlet, but they are 2-prong connectors. They also each have RF/coaxial cable coming into them from the cable company, and so those two devices are grounded by the RF cable instead.
If I connect the cable box to the TV via standard Composite/RCA/AV video cable, I get the grey scrolling horizontal bar hum, the usual symptom of a ground loop. BUT..
Inconsitency #1: If I instead connect the cable box to the TV using an RF cable, there is no problem! The scrolling streaks only occur when using an composite/AV video cable to connect the two devices. If the problem is a ground loop, shouldn't it occur either way, regardless of what type of connection cable I use *between* the two? And...
Inconsistency #2: Connecting my DVR to an RF modulator via AV video cable, and then from there to my old CRT television (only has RF input) causes no problem whatsoever. But if I use my new plasma TV in the *exact* same configuration, I get the scrolling ground loop hum bars. If it's a ground loop, shouldn't it occur regardles of which TV set I'm using? Or, is that because my old TV is 2-prong and so it's not grounded at the electrical socket?
As for solutions, what's the simplestway I can solve it? Can I buy a power bar/surge protector with at coaxial/RF connection, run my cable through that, and cause it therefore to be grounded at the same place as my plasma TV, assuming I also connect that to the same power bar?
Any help is greatly appreciated, thanks!