Help with interference: Plasma on wall

[oneyellowtang]

I have a Pioneer plasma (Elite) that we recently wall mounted in our living room.

As part of the install we put in a power outlet just behind the bottom right hand corner of the screen.

For the first week or so everything was fine, but as we plugged in more "stuff" (more HDMI cables in the back - XBox, etc.) I think the power cord got moved around, and now causes interference lines on the screen when on.

I'm pretty sure it's the power cord (based on what I've read in the forums - and when I move around the cord the pattern gets better/disappears). Having the power cord cross the signal line at a reasonable angle helps, but it seems to also be interefering with something else as well.

So first question: is there such a thing as a "heavily shielded' power cord? Can you solve this just through replacing the cord? If not, is there a way to shield the other side of the equation?

next question: other suggestions? (Besides placing the power cord at a reasonable angle to eliminate the interference, which is somewhat problematic given our set up).

Thanks,

- Matt

 

[TLS Guy]

I have a Pioneer plasma (Elite) that we recently wall mounted in our living room.

As part of the install we put in a power outlet just behind the bottom right hand corner of the screen.

For the first week or so everything was fine, but as we plugged in more "stuff" (more HDMI cables in the back - XBox, etc.) I think the power cord got moved around, and now causes interference lines on the screen when on.

I'm pretty sure it's the power cord (based on what I've read in the forums - and when I move around the cord the pattern gets better/disappears). Having the power cord cross the signal line at a reasonable angle helps, but it seems to also be interefering with something else as well.

So first question: is there such a thing as a "heavily shielded' power cord? Can you solve this just through replacing the cord? If not, is there a way to shield the other side of the equation?

next question: other suggestions? (Besides placing the power cord at a reasonable angle to eliminate the interference, which is somewhat problematic given our set up).

Thanks,

- Matt

I don't believe this problem is due to the power cord.

The key here is that this problem developed as you plugged more gear in.

You are describing exactly the effect of a ground loop. These are common, and due to a potential between grounds.

I would bet that your TV is on a different circuit from other parts of your system.

Do you have any hum or buzz from any speakers?

Unplug everything from the TV inputs, and I bet the interference stops.

Now plug each unit back one by one and see where the ground loop is arising.

Does your TV have a three pin plug? If so as a test, convert it to two pin with a two pin adapter as a ground break. I bet that also rids you of the problem.