Computer monitor ghost noise...

April 7, 2006 1:27 PM

What is this diagonal flow of visual noise across the screen of my computer monitor?

There is a steady, barely noticeable stream of visual "noise" running consistently and at all times from right to left at a 45 degree angle down the screen of my monitor.

What is it, or what causes it? It can't be interference from any devices I own, none of them are close enough. I suspect it's EM interference from something though. It's not really a problem as much as it is a curiosity. I've noticed it on other monitors as well.

Just in case someone asks, I'm running an Envision 19in monitor with a GeForce FX 5200 video card.

posted by mrmojoflying to Computers & Internet (2 answers total)

I'll assume it's a CRT monitor, and that it has to do with how the electron gun's timing is controlled. Try checking your V-Sync options to see if something can be changed there (or up the Hz of your display rate). They can also be caused by noise/interference on the VGA cable as B1 suggested. I'm sure someone that is more knowlegable will describe this a bit better.
posted by samsara at 1:57 PM on April 7, 2006

I live on a bus line in San Francisco (the 6 line) with overheard power cables, and if I get a CRT too close to the window/wall facing the street where they run, I see some very interesting noise on the CRT. I have mostly LCDs now, but I forgot about this recently when I plugged in my old G3 iMac and freaked out a bit when I put it on one side of the desk and it was completely wavering, and I slide it to the other side of the desk (2 feet maybe) and it's gone.

I have also noticed that big power transformers outside have even more interference.
posted by smallerdemon at 2:07 PM on April 7, 2006