Why does my telly buzz?

[diybry]

I've put a new aerial lead in because the picture kept breaking up with the old one, (terrestrial TV) and since then, there is a loud buzzing noise, especially when there's a lot of white on the screen. It doesn't come from the speakers, so some sort of power supply buzz is my guess.
On the plus side, the picture pixellation problem is fixed!
Any ideas guys?

 

[Cloth-Ears]

Check a fly has not got stuck.

 

[diybry]

No, however I removed an errant wasp before posting

 

[Bungle]

Is it a plasma screen, as I recall reading that they buzz when the screen is white for reasons that escape me.

 

[diybry]

It's an LED set, 47" or thereabouts. Panasonic

 

[Minstrel SE]

You wanna hear my CRT telly buzzing away. I think its on its last legs

Its was supposed to have packed up 7 years ago and I have the glass 3 shelf table ready for a flatscreen.

I will probably be ready for a new telly when 4K becomes affordable