SPCR

I've been sitting in my quiet room tonight and have noticed a buzzing noise eminating from my Dell Mini9. It wasn't there before. It sounds like electrical noise, and appears to be eminating from the underside - opposite the touch pad. Any ideas what could be causing this noise?

Could the Mini 9 recieving a knock or two (while off, or on standby) have changed things?

I'm very confused, and quite annoyed. Late at night, with very little other sound, this electrical type noise is audible, and of a very annoying sound character.

Any ideas whats going on? and anything I can do about it?

Turn down your speakers

Does it do it when plugged into the charger or standalone or both?

speakers on mute

both on charger and stand alone (although the charger also makes a faint buzzing noise)

Raise and lower the screen brightness and see if the noise changes.

checked the brightness bit as well, it seems to be constant.

so, it's probably not the power circuitry for the charger/battery or the display... usually a buzzing sound is associated with an inductor coil in a power circuit...could be your cpu power regulation or something else. is it under warranty? maybe it's a replaceable/fixable thing.