Green dots on monitor

[Bluntey45]

Hey guys, I was attempting to move my computer about 50ft away from my desk. Everything worked fine except one 6yr old 22" samsung monitor. With the normal DVI cables it works fine, but the 50ft one made it have green dots on it. It's not the cables, because I have two monitors and it works fine on my newer Asus 23" monitor. Any suggestions? Should I try and buy a DVI to hdmi adapter and try it that way? They don't make many 50ft dvi cables and they are expensive. I don't know why this is happening, I tried both 50ft dvi cables and neither will work, but they both work fine on my newer monitor. Any idea why this is happening? I tried different HZ and everything when plugging in the new cables to it.

 

[Burpo]

It could well depend on where you're running the 50ft cable. If near any florescent lights (or other high voltage lines), that can cause interference. DVI cables are more susceptible to interference than other cables, and the Samsung monitor may be picking up crosstalk, while the newer monitor may not be affected.

 

[Bluntey45]

I'm just running it out of the room into an open type hallway closet, nothing else is around it. The cable is passing through a TV but that's about it. I moved the monitor into the hallway and tried it with the short cable and it worked fine. It also works fine on the regular more expensive monitor. Should I try buying a dvi to hdmi adapter and trying it with a hdmi cable? Is it possible that my monitor just doesn't play well with a 50ft dvi cable? I don't get it. I'm going to try it in it's normal spot with the long cable and will report back.

edit: yeah, I tried it normally with the 50ft cable and it's still happening. Green dots on dark spots of the picture, when I restart the computer and the monitor is black there is a lot of green, but with the normal cable it's still fine.

 

[Burpo]

Why don't you just switch monitors if the Sammy doesn't like it?

 

[Bluntey45]

I'm using two monitors, have been using these two for years, I would have to buy a newer asus monitor if I can't figure this out.

 

[Ketchup]

DVI is only rated up to 15 ft. HDMI would be needed for the lengths you are talking about, and you may need a booster (but I would at least try it without one for starters.)