Hi, I just got an ACD 20" that I bought from somebody. Never been used before. I am using it as a second display to my MacBook Pro 15" Beautiful monitor!! There is one curious thing that I have found. As I turn the brightness higher, I notice that the white power brick begins buzzing audibly. I can especially hear it if you stand it up (i.e not laying on its back). Is this common? Does anyone else hear this? The monitor was bought in December 2007, so it is still under the 1 year warranty where I could have the power brick replaced, right? Thanks a lot!