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Discussion Starter · #1 ·
Hello.


I wasn't sure which forum to post this to, since the problem involves a number of components.


Recently I have noticed a semi-transparent horizontal line scrolling from the bottom of my display to the top, then repeating. It's very light, and does not show up against dark backgrounds.


Here are the components involved and set up: Arcam DV27 DVD player connected to Pioneer VSX-49TX receiver via progressive component from the Arcam, and also non-progressive connection, (both to the Pioneer).


I use the Pioneer for video switching, and it is connected via component to a Sanyo PLV60HT projector.


The reason I have two connections from the Arcam is some of my DVD's are PAL, and my model DVD player does not support PAL progressive, so in order to get the DVD to frame properly, I used the non-progressive output from the Pioneer.


The Arcam is set to Auto for both region and video (switches between NTSC and PAL), the Sanyo is also set to auto.


For quite some time this set up has worked perfectly, but as mentioned above, I am now getting this scrolling horizontal line (sometimes more than 1), which is very distracting.


One thing I have noticed is that when playing PAL DVD's, either via the progressive or non-progressive output from the Pioneer, the line(s) are not present.


I'm not sure about the best way to troubleshoot this, since I don't have another display device to test on (i.e. no PAL TV). I am hoping that someone might be able to diagnose the problem from the symptoms.


With my limited knowledge, I am not sure if the problem is in the DVD player, video switching by the Pioneer, or, the projector.


Any help would be greatly appreciated.


Thanks in advance....


Tom
 

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TomT:

Sounds like it might be a ground loop. Dealing with a ground loop can be tricky... I had to call in a couple of electricians (the first couldn't fix it) before I was able to rid my system of a similar problem.
 

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Discussion Starter · #3 ·
mnilan,


Thanks for your reply. What exactly is a ground loop? Would that affect all connections and formats? E.g. the problem is not present when playing PAL material. That makes me suspect my projector....
 

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TomT:

A ground loop is where there is a problem with the completeness of an electrical wiring system's ground. The system can be grounded at one point but still have noise indicating inadequate grounding. The only place you will notice this is on your display and not all sources will show the problem.


I am sorry that I do not have a more precise technical explanation for you. In my case, I was getting a rolling line (from bottom to top) when I watched certain channels but not others (e.g., when I watched analog channels but not HD channels). Nor was I getting it when I watched DVDs. Two electricians and two grounding rods (eight foot copper rods driven into the ground) later and I don't get the rolling line any more.


Your problem may certainly be something else, but it does sound similar to mine...


Good luck!
 

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Discussion Starter · #5 ·
I finally found the problem. I had noticed around the same time this started happening, a low frequency hum coming out of my speakers.


I finally tracked that down to the cable attached to my TV. I called the cable company, and a tech came out and determined the cable was not grounded properly. He fixed that, and all the problems were cleared up. One other symptom was sometimes the picture would roll vertically.


He said the lines on the display were (as I recall) a 60 cycle hum, which usually means a bad ground.


I am so grateful to this guy, I could have spent untold hours trying to figure this out.....


Thanks again for your help.
 
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