Sharp Microwave: line buzz when *OFF*

[slantsixdan]

Sharp 900w household µwave oven, model R-4A46C, serial 112193. It's emitting a 60-cycle (line current) buzz when plugged in but not powered up. It's been doing so for quite some time—years—but seems recently to have been gradually growing louder. Four months ago, you had to have the kitchen silent and lean down next to the µwave to hear it, now you still need the kitchen quiet, but you can hear it by just standing still and listening. I find this puzzling; the only parts that are active when the unit's not in a cooking mode are those related to the vacuum-fluorescent clock display, as it seems to me. Perhaps there's a transformer involved?

The buzz itself is tolerable; what concerns me is whether this indicates impending dangerous failure with risk of fire.

TIA as always.

[AccApp]

Is there a working radio nearby? You can put some music on until the unit fails and then go buy a new one.

Seriously, it sounds like a transformer, there is probably a Low Voltage trans which is causing the buzz. I wouldn't worry about it.

[slantsixdan]

Thanks, 'preciate it!