QRM/QRN takes me out

Over the weekend I noticed a buzzing sound about every 10Khz on 40 meters. Checking further I found it was on all bands. It is not a weak signal, its 20 over S9!
I have no idea where the source of this new interference is but until I find it and get it removed I am unable to operate. Never in 56 years have I seen external noise this strong. I am thnking it maybe a wall wart gone sour and boy do we have a lot of them in this house. Will start my search by turning off circut breakers for different areas of the house to see if it is within our house or perhaps a neighbor.