old monitor causes flicker on new monitor near it

papasmurf

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Apr 14, 2002
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I have this old monitor 15in made by...kenetic hmmm yeah it sucks but I am running my server here and I have to have this monitor right here there is nowhere else for it but right next to my other monitor. when I turn on the old monitor I get this line that keeps running up the screen of my new one and it is sooo annoying. any ideas about what could be causing it? it is like when you see a monitor on tv and it has those horizontal lines going up over and over... help!

Pull the lips over the gums look out testicles here I come! -What is that from?
 
It's probably the "beat" frequency between the refresh rates of the two monitors an effect not unlike moving your arm through a strobe light... an optical rather than an electronic effect.

Not much you can do about it except move them further apart.


--->It ain't better if it don't work<---
 
Could be, but I sorta doubt it. That would take A LOT of light from one monitor to interfere with visual perception of another monitor.

Try this: turn both monitors on, and put a book or something else opaque in front of the monitor that does not display the problem. Does the offending monitor still display the problem? If so (and most likely), it's not a perceptual problem.

My guess is that it is an electrical or magnetic interference either between monitors or between cables.

I once needed to do a 2 monitor setup, but I was afraid to buy big expensive monitors for the task: I didn't want the magnetism from one monitor to screw up the neighboring monitor. But that was when big monitors cost more than cars, so I just didn't want to take any chances. I always wonder how many multimonitor setups (CRT) have problems with one screen interfering electrically or magnetically with the others. And I've never been willing to risk a good monitor to find out!
 
GoatCheese

You are correct. It is magnetic. Magnetic fields and monitors do not get along. Monitors use an Electro magnetic field to deflect the electron beam across the screen. Thus monitors are very susceptible to external magnetic fields even those created by another monitor close by.

What you're seeing is mutual magnetic interference between the two monitors. They are not running at EXACTLY the same rate, the movement you see is moving at the "beat frequency" (difference in rates) between the two. The only cure is to physically separate the monitors. Angle the rear of the monitors away from each other, this sometimes helps. Change the refresh rate to see if you can find a combination where the result of the interference isn't as objectionable.
This will not harm the monitors.

Jim Witkowski
Chief Hardware Engineer
MonitorsDirect.com


<A HREF="http://www.monitorsdirect.com" target="_new">MonitorsDirect.com</A>
 
I suspected it was magnetic. I tried changing refresh rates but no combination seems to work. I suppose I have to live with it. If only lcds weren't so damned expensive, I certainly don't have 1000 bucks for 2 17 inch lcds.

Pull the lips over the gums look out testicles here I come! -What is that from?
 
just a thought and could be a cheap fix try putting something aluminum between the 2 monitors. Aluminum has very peculiar magnetic properties. It reacts magnetically to changes in electromagnetic fields. That's a little how rail guns and mag lev trains work. Try a sheet of aluminum foil between them and see if there is a noticable difference. BTW make sure that shield spans from the front of the side to the back of the side since the tube inside also spans that depth.

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It is magnetic interference. Place a large magnet beside the monitor (like an unshielded speaker), and watch the distortion. I've heard you can permanently damage the monitor by doing this, but I don't know any facts on it.

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You can indeed periminently mess up a monitor with a magnet. It polarizes the HV mesh in the tube and really screws up the colour purity.

It can sometimes be mostly undone with a sufficiently strong AC magnetic field to "Degauss" it... but the thing seldom looks right after.

Don't put powerful magnets anywhere near a monitor... unless you are willing to scrap it.


--->It ain't better if it don't work<---