Hope you have that guy on a good surge protector. I'm sure you were getting excessive power sent down the line. AC power is unreliable and for electronics, computers and other sensitive equipment. There is too much fluctuation, example, if you are in a room with lights on, and they will dim when an appliance is turned on. The appliance is starting and uses more power to start, once it's going it uses less. This happens on the entire block, or where the transformer is feeding the homes. It will go up and down, and the only control is to add a power conditioner. If it goes off during a storm, unplug all your shit! When it returns it surges, and this will fry an AVR-TV. PC amps, anything electronic. My aunt had her stove fry, it was all digital.
A good trick is get a inexpensive AC power meter, and watch it go up and down. AC is rated at 110-115 volts, It will exceed 115 often is short bursts, and the amps will go up. Then drop below 110.
When they had no power, you were getting overflow, this is why the humming.