PNY 7300GT rising bars/lines

[OttoNP]

I have rising bars on my TV. I'm using a 7300 GT svideo output with nvidia prodecoder. I almost can't see them during normal scenes, but they are very visible when screen is black, even when I pause it. I've tried various cables with no luck and it occurs if I use RCA as well.

I'm thinking about taking back the graphics card, any suggestions....

[Polypro]

Ground loop interference?

"Ground loops commonly cause humming noise to audio signals and interference bars to picture".

From: http://www.epanorama.net/documents/groundloop/

Google: http://www.google.com/search?client=...utf-8&oe=utf-8

P

[OttoNP]

I believe I can eliminate ground loop interferance becuase I can see them when using a LCD monitor and computer only away from everything else (tv, receiver, etc..) Same circuit breaker and outlet (common ground). I have found that they seem to only be present when refresh rate is 60 hz (which lines up with AC power freq). I'm under the impression that I have to use 60 hz with my TV, svideo input, so I can't just change that, right? Since it lines up with power freq, I think it may be my power supply. I'm using a coolermaster 300W, when I measure my actual power use, it is around 100W.

[zoundz]

No matter what your configuration, if you are seeing diffuse horizontal bars that move up the screen slowly, you are seeing hum bars. They are the result of a ground problem, but not necessarily a power line ground problem. You should check all of your cable and satellite grounds as well and make sure that all your F connectors are securely tightened. Also make sure that none of your F connector shells or splitters are in contact with grounded metal. These problems can be hard to sus out, but rest assured that the artifacts you are seeing ARE 60 Hz hum related somehow.

[OttoNP]

Good call zoundz, too bad I didn't check back sooner as I went through the story below to resolve my issue. I still have a questions though, in the end the noise disappeared when I ran the cable tv cable through my power strip (it has cable protection too), which I believed resolved the issue by grounding the outer shell of the cable connector, but your post states to avoid grounding the outer shell. This seems impossible to do since the metal on capture cards touches outer shell of cable which touches the chassis of the computer which I believe is grounded, thoughts? During my process of elimination, I disconnected splitter and ran right from cable tv in to my capture card, which I believed grounds the outer shell of cable, and lines where still present.

My Story Below:
I resolved this issue. I was trying another power supply when I noticed the lines were present on the TV even when power supply was removed (computer off), I then unhooked various connections to the computer until the lines disappeared. The "noise" was coming in on my cable tv cable that connects to my capture card. When I woud disconnect this cable, the lines would go away. I then reconnected the power supply and verfied that the lines were gone during playback and other conditions. Reconnected cable for cable tv would case the lines to reappear. So, the "noise" source is apparantly cable TV cable and it is going into capture card and somehow making its way to graphics card and being sent out on it, is there anything in place in the graphics card that should be preventing this transfer? My circuit breaker has a cable in/out jack on it and after running cable through that the lines disappeared. So, when the cable coming in from the cable company is directly connected to my capture card the "noise" is present, but when the cable comes in from the cable company and then is connected to my fancy power strip, then goes from my fancy power strip to capture card, the noise is gone. My guess is that the outer connected is grounded in the power strip, but I would think that it is also grounded on my capture card....

Originally Posted by zoundz

No matter what your configuration, if you are seeing diffuse horizontal bars that move up the screen slowly, you are seeing hum bars. They are the result of a ground problem, but not necessarily a power line ground problem. You should check all of your cable and satellite grounds as well and make sure that all your F connectors are securely tightened. Also make sure that none of your F connector shells or splitters are in contact with grounded metal. These problems can be hard to sus out, but rest assured that the artifacts you are seeing ARE 60 Hz hum related somehow.