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Discussion Starter · #1 ·
I made a vga component breakout cable with Cat5e. Overall it looks great - but I noticed a rolling bar moving up the screen. What is causing this? Unshielded cable? Is the timeing off?


I want to try and fix this cable before I go blow $100 on a premade cable.


thanks in advance for the help.
 

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Cat 5e is not suitable for VGA. A proper VGA cable has 3 of the lines shielded, I believe they are the Red, Green and Blue signals. However rolling bars most often cause by a ground loop. Try isolating the ground with a 2 prong adapter.
 

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For the love of all things that are not "silly", if your device comes with a three prong adapter there is a reason.


That little third pin isn't for looks...really it isn't. Allot of times your equipment case and quite a few bit and pieces of your electronics are attached to that ground. So if you break that ground you are jeopardizing your system to ESD and also potentially killing yourself :rolleyes: Please trust and electrical engineer who works in the power electronics business. I have seen other engineers who though it was cool in their own house to lift the ground on some of their home equipment then get thrown across the room when they get zapped or hear a pop inside and see some smoke come out when they ESD it.


If at all possible, only break ground loops at the signal level...never the power level.


-tReP
 

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Discussion Starter · #4 ·
So if I break the ground loop - the rolling bars could go away - but if I do - I could die. hmmmmm, what to do what to do....


In any event -- I don't see a solution here yet. I'm guessing it is because the cable is not shielded - and it has to run near AC power (obviously) when it plugs into the back of my dvd player. However, I'd rather not rip down my sweet-ass wireing job on a guess.


Anymore recommendations before I start randomly grasping for straws???


--Eric
 

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bigwo2000:

You have identified that you have a ground loop problem. This means there is a difference in the voltage level of the ground at the outlets involved. Many things can cause this. Usually this is caused by either a bad connection in the ground circuit or a device plugged into the circuit bleeding voltage in to the ground. Start by unplugging everything not needed along both circuits. If this does not isolate the problem turn off as many breakers as you can to remove power from every thing else in the house. If the problem is still not isolated it is possibly caused by a poor ground connection at one of the outlets along the circuit. At this point you need the check the ground wiring at each outlet in the circuit and insure the connections are tight and secure. If do not have the training and skills to do any this yourself get a professional electrician to find the problem. In the end you want to use the devices with the grounds connected.
 
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