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Discussion Starter · #1 ·
Hi group,



I think this is an electrical problem. I see very faint purple lines that roll slowly up my screen (especially during dark scenes). I see it with all my inputs..dvd, DVHS, and HD sat receiver. I noticed that it is worse if my wife runs the washing machine or dryer..etc. But it is still there even when nothing is running in the background. I bought a monster power strip that says it filters "dirty" AC noise and I think it has helped, but it has not gone away completely. I would appreciate any help or suggestions you experts could give me.


Thanks in advance,



Kevin
 

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I went through this also. Originally I thought it was ground loop so bought a cable ground fault interuptor (sorry if that's not the proper description, it breaks the loop somehow). That made things MUCH worse in my case. It basically cut off the picture altogether. So then I bought a cable amplifier to make up for the lost picture. Nope.

I disconnected it and being lazy at the time left it alone and lived with the banding. I unhooked my system entirely a week later, re-hooked it up and it was 10 times worse.

There was a bunch of (disconnected!) loose wires just sitting on top of the other hooked up wires so I picked them up so I could get at the hooked up wires. It was WAY better! So I separated all the wires by a reasonable distance and made sure anything close was as much as possible crossing at 90°. Done, problem fixed. The problem in my case was just too much darn wiring near others.

Make sure your wiring doesn't run too close in parrallel, especially different types of wiring (cable vs. power, vs. speaker wire, vs interconnect). I now have NO banding at all. Yours may be a ground loop, mine was just bad wiring.
 

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I agree 100% with grantv, it's an interference problem (noise in the vertical sync signal - it's 60 Hz also).


It could be wire placement or even a bad shield on a cable. Move your cables around first, that should give you an indication of what's happening. It almost sounds like you've got your AC power cable running along side the video cable and are getting coupling.
 

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Discussion Starter · #5 ·
Thank you all for your quick responses. This now gives me somewhere to start. I will let you all know what happens. And again thank you all.
 

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I had suddenly developed a rolling lines problem over the week, after I had added few pieces of new equipment (vga amp/distributor). So I thought it was that, until I removed and unplugged power to the new equip and my system was back to its previous configuration.


... Yet the rolling lines STAYED! I tried just reducing the equation down to source + amp + display, which did not cure the problem.


So just out of pure frustration, I unplugged everything including speaker wire and interconnects, straightened them all out, and untangled them (they suffered from the *damn wire, I'll just kick you under the table syndrome*). And surprisingly, the problem went away, so I'll guess I was picking up interference from wires.
 

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I had this problem. I bought a cheap 2-prong plug adapter and plugged my projector into it to ensure it was a ground loop. Sure enough, the rolling lines disappeared. Not wanting to get electrocuted at some point in the future, I bought this:

http://www.partsexpress.com/pe/showd...number=180-075


and installed it on my cable. When I plugged the projector back into the grounded outlet, the problem was gone.


Ricketty
 

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Also check the cable connection outside your home where is is connected to the grouding rod. Mine was connected poorly and was loose by the cable co, causing my ground loop. Cleaning and securing this connection outside my home eliminated the problem for me.
 

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Discussion Starter · #9 ·
Hey guys,


I did the 3 prong to 2 prong thing and it seems to have worked? What do you guys recommend I do for a next step? Is it OK to leave it like that or do I really need to go further with this?
 

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You could leave it like that for years and never have a problem with it. On the other hand, if for some reason a short develops in the projector and someone touches it, it could be *shocking* or possibly even fatal. It isn't worth the risk, even if the risk is small.
 
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