My 10v "MacBook nano" has a high-pitched up that seems to emanate from the middle of the keyboard when it's plugged in.
It's slightly higher in frequency than an old CRT TV's transformer, and quite loud.
On battery power, the hum goes away.
Any ideas for a quick fix, or do I need to un-Macify it and send it to Dell?
PS: I don't know if the hum was there before I installed the 2GB memory chip or not, as I did that before I ever fired the machine up. The computer was disassembled and the chip installed per guides on this forum.