The receiver appears to be fine but may not be.
In the set up menu there is a setting for balancing the channels that puts noise into each speaker. If you can't get any noise then the receiver is at fault. You can try to reset it but it may need to be serviced.
If you do get noise then try running the full set up. It may have been lost during the power outage. Make sure that your TV or sources have't lost their setting. If you get your audio from the TV optical out it may have defaulted to turning that off.