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Discussion Starter · #1 ·
I'm having an annoying problem with artifacts on certain cable TV channels and i'm trying to determine what the source is - the signal from the wall, my cable box, or my TV.


The artifacts appear in one of two ways - either there is green/pink macroblocking on the edges of the picture, or there are random snow artifacts. The big one lately that has been showing up is the snow, and i've attached some pictures with the TV paused to show what i'm referring to. Most of the snow is white, but not all. Occassionally the artifacts are blue/red as you can see below. The specks stay on screen for about 1/3 second and they change location on the screen constantly. Any thoughts on where these might be originating at?

 

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You haven't provided any details but from what you describe it sounds to me most likely to be an HDMI cable problem.
 

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Discussion Starter · #3 ·
That was my first thought. When I previously had this problem (it started up again recently), I purchased a replacement HDMI cable since that was the easiest thing to check. But the 'snow' still persisted. I ruled out the HDMI cable as the cause.


I left it alone, and the snow disappeared mysteriously on its own for about three months. Only recently did it start up again, coincidentally one day maybe two after buying a Wii and setting it up for my TV. Thinking there was some kind of cable shielding issue going on, I completely redid the jumble of wiring behind the TV and made a point to separate all cables from each other. But that did no good either. Now i'm grasping at straws again as to the cause of this.
 

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Try using component cables to see if the same problem persists.
 

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You should use a test pattern to isolate the problem. Have you hooked up a DVD player to this input? Do you have a calibration DVD, like Digital Video Essentials?


Do you have HDNet available? They run a 10 minute test pattern calibration program every Saturday AM. I record this on my DVR for checking problems just like this. It will instantly tell if the problem is your STB.


Sat, Mar 13 - 6:30 AM ET 3:30 AM PT HDNet Test Patterns

Wonder how your home theatre is doing? Wish you had test patterns to help set it up? Well, HDNet is here to help. This short program will help you get the most out of your home theatre setup by providing you with the same professional test patterns HDNet uses to set their gear.


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Another thought. The problem reappeared after you installed your Wii. I'd remove the Wii from the TV and see if anything changes. Try moving a cable around. Perhaps a connection got crushed somewhere.
 

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Discussion Starter · #6 ·
I just tried the component video cables that came with the box but the snow still remains even on component. I'm kind of relieved because I was worried it could be an issue with the HDMI in my TV. My Xbox360 is hooked up via component and i've never seen any artifacts of any kind on it. So i'm guessing it's down to the cable box or the actual signal coming in from outside?


I do have HDnet, I wasn't aware they had that test pattern available. I'll try to record it next Saturday and check it out.
 

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Quote:
Originally Posted by MarkJC /forum/post/18265532


I just tried the component video cables that came with the box but the snow still remains even on component. So i'm guessing it's down to the cable box or the actual signal coming in from outside?

I'd say so.


Try a hard power cycle of the cable box (unplug from wall power for a few minutes). If problem persists... call your cable provider.
 

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From your two screenshots it just looks like normal HD cable overcompression to me. That was one of the biggest reasons I dropped Comcast and went to D*. I haven't regretted it a day since then.
 
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