monitor buzzing

[ang3]

i left for work with my monitors on and came back 8 hours later and i hear this buzzing coming from one of my monitors. sound still comes out of it and the sound quality is the same but the buzz remains contant. also when i power off, it makes a loud pop everytime. i unplugged it except the power and it still buzzes. anyone know whats wrong? they are m-audios bx5a, had them around 5 years.

 

[viralz]

''unplugged it except the power'' How is that possible?

 

[Empathy]

Tried plugging it in to a different power socket? One that isn't chaining other devices?

 

[ang3]

''unplugged it except the power'' How is that possible?

i meant from the interface

tried different power sockets and different power cables. still buzzing. the buzz sounds like an electric razor but not as loud. it sounds like someone is shaving from a distance.