I recently got a new laptop for work ( I’m being forced to use Windows, but that’s a different story, haha. Cygwin + zsh makes it bearable but I really miss WMII ).

Anyhow, I was having terrible monitor flicker with my external monitor. I noticed that the flicker would appear anytime I hooked up my power brick to my laptop and it would magically stop anytime I unplugged it.

At first I just chalked it up to Dell’s shoddy construction as I never had a problem with my Viao. However, after crawling the web I finally stumbled across this solution:

Are you having problems with a flickering external monitor on your laptop?

Does the flicker go away if you remove the laptop charger?

If you answered yes to the above questions, you probably have a ground loop. Slimplified this is because the monitor is grounded (using a 3 prong coord) and the laptop is not grounded.

The power brick was grounded but I guess the laptop wasn’t ( which makes sense as the connector is one of those round jobbies which can only have two “prongs”.

I wrapped some tape around the ground prong and then like magic the flicker stopped I still don’t understand why I had no problems with the Viao though, so it could be a problem with the laptop’s construction … maybe the connectors aren’t shielded ( or something )

You can read the entire blog post that I quoted above on Mr. Gnome’s Blog.