Buzz on Mitsubishi TV

The tv is about 7 years old, with picture tube. It's a 25". When the tv comes on, there is a noticible buzz immediately, sort of like a two cycle motor when ideling. It stays the same pitch and is most noticible when the cable box cable is connected to the tv. With the cable unplugged, the buzz diminishes to negligible and is at a much slower pace. Also, there is a 1/2 inch black space at the bottom of screen and the foreheads of people are very enlarged. Could this be a filter capacitor in the power supply or any other ideas