I would first check any of your inputs (i.e. cable, satellite, DVD player, ect...). If you hear this buzzing sound regardless of what input you are using, then it has to be the TV. If it's the TV causing it, audio is produced on the main board or A board named by Panasonic. It is the board that has the A/V inputs on it (cable, HDMI, component). This model has 2 different main boards it could use either TNPH0721ACS or TNPH0721ATS. As a TV repair technician, I often use Tri-State Module and would recommend them for parts. If you don't know which board you need, their customer service is helpful. I hope that helps.