Emishore

I am using a PDA for the first time, so I do appologize if the following question will sound silly
Is it normal to hear a little buzzing noise when the screen is on? If the device is in stand-by there is no noise whatsoever, yet as soon as I activate it, there is this low level buzzing noise (it sounds like a AC power adapter / transformer)
Should I have the device checked out by a hp service representative? I don't mind the noise itself, as I am using a bluetooth headset, but I don't want any further problems :(

And I would like to take this opportunity to show my appreciation for everybody posting on this site, it is a great source of information, especially for the new users.
Thank you once again, and keep up the good work!