nVidia tv-out makes a humming noise on tv
 

I have an nVidia GeForce 4 MX 440 video card with an S-Video TV-out port on it. When I try to connect it to my TV i get a low-level hum coming out of the TV speakers. This is really strange considering it is just a video signal that I am sending.

At first I thought it might be a driver problem, but after updating with the most recent nVidia drivers, the problem continues, and upon closForum Rules:er inspection, the humming begins as soon as I turn the computer on. Also, as soon as I even touch the back of the computer with the S-Video cable, I get the humming noise...

My only thought is that there could be some kind of interference coming from something, but I have used it before with no problems. Does anyone have any ideas as to what could be happening?

The hum is typically caused by a ground-loop.

Make sure that the computer and TV are connected to the same outlet, that the outlet is properly wired and grounded. If the problem continues, some TVs have a ground wire connection; you can run a wire connected to this to a ground point on the laptop - for example, the post on a serial or parallel connector.

I tried hooking the tv and computer to the same outlet, but that did not really do anything. As far as I can tell, there is no specific ground point on the television, do you have to hook the ground wire up specifically to the ground point or will any metal piece do?

The problem with "any metal piece" is that it may not be connected to anything.

You can also try connecting your laptop's audio-out to the TV's audio-in. The floating value between the video and audio on the TV can also cause the problem. If you're not using the TV audio, you can just mute it to eliminate the hum.