M-Audio BX5 that I've had for 3-4 years recently started giving me a rather intrusive buzz whenever it's powered up, regardless of whether there's an input or not. 'Til now had been fine, no recent trauma either. Repairs would cost as much as a new device. Given that it's shot anyway by that standard, figured I'd open her up and see if I can't swap something out on my own. Any 'philes able to give me a recommendation of what components I might want to take a look at given those symptoms?