Herringbone pattern on TV

I have a large screen Sony TV connected to a satellite receiver. One TV output goes to the VCR and the VCR audio output goes to a small stereo system. It has worked fine until recently. A slight herringbone pattern develops when the stereo system is turned on, whether watching a tape or watching live TV through the VCR.. It vanishes if you turn off the stereo. There is no problem if you watch the satellite directly, i.e.. not through the VCR. I suspect a loose or dirty connection or possibly a bad ground. Before I go grovelling about the maze of wires on the floor behind the whole set up, am I on the right track? Or maybe there's something else I haven't considered. Thanks ds
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Maybe the shielding on a cable is bad. You could also test the outlet for a bad ground with one of the cheap outlet testers from Radio Shack.

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I just went through some similar nonsense with my cable company. They replaced all of the outside connections, like 4-5 years old. Still did not fix the problem. I replaced the incoming cable and finally the problem went away. Check and see if the ground is clean and connected; that can be an issue as well. (cables). Have you changed anything since the problem started?
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You might get better information if you posted this question in sci.electronics.repair. Des
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Dick:
DS> I have a large screen Sony TV connected to a satellite receiver. One TV DS> output goes to the VCR and the VCR audio output goes to a small stereo DS> system. It has worked fine until recently. A slight herringbone pattern DS> develops when the stereo system is turned on, whether watching a tape or DS> watching live TV through the VCR.. It vanishes if you turn off the stereo. As the others indicated, first check for proper grounding and shielding. Use good-quality cable: generally the smaller the diameter of the coax the less shielding it will offer. (Compare RG-8/U to RG-58/U.)
Another potential problem is the IF (intermediate frequency) stages of your receiver(s). IIRC the IF for FM is 10.7 MHz. This means the FM receiver can create a signal which is in the TV band. Is is possible for the signal to travel through the center conductor so the best grounding and shielding in the world won't remove the herringbone.
You've done part of the testing: when the stereo receiver is on you notice interference and when off it's gone. Now for a couple other tests. Does changing the (FM) station remove the interference? If it does that pretty much points to IF leakage. Is it possible to move the stereo? I have an integrated receiver on a shelf above my monitor. The power transformer (or power supply) causes a slight wiggling of the image on the CRT in the upper left. As it would be inconvenient to move things around I put up with it, just move the display so the section I'm working on/viewing isn't at upper left.
- barry.martinATthesafebbs.zeppole.com
* I suppose there's some sort of poetic justice to this. If so, it eludes me.
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Nearly always the cause is bad connectors. The ones that "screw" onto the coax are especially prone to failing. Even the good ones that require the $30 cruncher tool to put on can fail, but it's much less likely. Of course, you simply can't use the cheapo Radio Shack coax with the aluminum foil shield. I find the RG-6/U (hearvy duty shield) to be best and Home Depot sells it buy the foot.
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