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Rolling Interference on Panasonice Plazma

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Reins
Rolling Interference on Panasonice Plazma
on Apr 17, 2006 at 9:09:55 pm

Hope someone can help.

We bought a new Panasonic TH-42PHD8 Plazma Monitor (client wow factor). After about a week I noticed a weird horizontal interference crawl with a purple hue slowly moving upwards through the frame. The width of the interference band isn't constant, but the speed at which it loops is always pretty slow.

The monitor is connected through a patchbay, and it doesn't matter what source is fed to it, the crawl won't go away. We plugged it straight into a UPS battery, and fed a signal straight from a deck, but no luck.

The owner of my company is really angry, but I have had little success with the people at Panasonic. We live in a small city with limited video engineers, so my options on local help are short.

Any ideas on what would cause this interference and how to treat it?

Thanks in advance,
Reins


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Thax
Re: Rolling Interference on Panasonice Plazma
by
on Apr 17, 2006 at 11:30:48 pm

Did you "lift" the grounding pin on the power plug?

Do you have a "hum-bucker" you can feed the input device through before it connects to the monitor?

Is the monitor ITSELF bolted to a metal strip or rack that might be GROUNDED?
(That could cause a ground-loop from the playback device / router to the monitor.

Last resort:
Take the monitor off the wall, sit it on carpet (no grounding anywhere).
Connect its power cord to the same outlet as a standalone deck, which is feeding the monitor directly.

If that still gives you a hum-bar (or whatever it is) it would look to be the Monitor's problem.

What does it look like "off-air" via its own tuner?


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Reins
Re: Rolling Interference on Panasonice Plazma
on Apr 18, 2006 at 3:46:30 pm

Thanks for your response Thax. Mostly, I was looking for a name to my problem and now I know it has to be a "ground-loop" problem.
There seems to be a couple of different solutions to my problem. Now I have more quesstions:

Will getting a hum-bucker solve the problem or just hide it? Should I have an electrician come in and try to fix the grounding? Could other machines be effected by the problem and we're just not seeing it?

I found a very good article on all of this:
http://www.epanorama.net/documents/groundloop/video_isolation.html


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Thax
Re: Rolling Interference on Panasonice Plazma
by
on Apr 18, 2006 at 5:11:22 pm

A "ground-loop" is a very common problem, but its not a "serious" problem.

If you can get an in-line video "hum-bucker" to work, that's all it takes... it won't "mask" the problem, it will simply eliminate the conditions that CAUSE it.

If you are SURE that this is the only problem... you're in good shape.



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