I am a Comcast subscriber, using Comcasts' Motorola DCT 3416 I box, running through my HK AVR-240 which has my Panasonic Viera 58 inch plasma also connected. The problem is about 8 - 10 months ago a horizontal line began scrolling through the video display, whether viewing a Comcast broadcast (HD or not) or watching a DVD. When I disconnect Comast's incoming line from their box or put a suppression filter between their incoming line and their box, the horizontal line goes away. The problem with the suppression filter is that is creates pixeling on HD channels and sometimes completetly blocks the signal. Comcast has dropped a new line as well as ensured their system was properly grounded (it was not grounded intially). However, the problem persists. So now they say the problem is electrical feedback from another source within my home and that when the horizontal line appears, I should unplug items in my home until the line disappears and then I will know the source of the feedback. Yet, when I disconnect their incoming line or as stated put the filter between their line and their box the horizontal line does disappear. Any ideas for help?