Question Possible ground loop from coaxial cable(comcast)?

[shafe88]

Just connected my cable box(DVR) to my computers TV tuner(connected via S-Video) and noticed a hum in the audio and a bar(where the image is hair darker) that scrolls from the bottom of the top repeatably, I remove the coaxial cable from my cable box and both the humming and scrolling bar goes away. Also noticed with the coaxial cable disconnected, that touching the screw part of the coaxial cable on the coaxial input on the box causes the symptom to reappear.

 

[kanewolf]

Just connected my cable box(DVR) to my computers TV tuner(connected via S-Video) and noticed a hum in the audio and a bar(where the image is hair darker) that scrolls from the bottom of the top repeatably, I remove the coaxial cable from my cable box and both the humming and scrolling bar goes away. Also noticed with the coaxial cable disconnected, that touching the screw part of the coaxial cable on the coaxial input on the box causes the symptom to reappear.

That sounds like a ground loop. Does your PC have a 3 prong power cord?

 

[shafe88]

That sounds like a ground loop. Does your PC have a 3 prong power cord?

Yes it does and it's connected to a smart power strip that's connected to a 3 prong outlet. Currently rigged up a temporary fix, replaced the screw on coaxial cable with an old one I found that just pushes on, before installing the push on coaxial cable, I wrapped the coaxial input on the cable box with a piece of electrical tape which seems to have worked as a temporary fix. Don't have this ground loop problem on my TV which is connected via HDMI, just my computer which is connected via S-Video and composite(audio)