iMac has a buzzing noise on the top back left corner
I have a mid 2011 27inch Imac 3.4 GHz , i7 ,8GB. Recently there has been a buzzing noise that comes out the top back left corner. when i increase the brightness of the screen the buzzing noise becomes louder when I decrease the brightness the noise stays the same.
I have seen youtube videos of people recording the buzzing noise and some say it is a faulty power supply or the LED driver board.
Has anyone heard about this? and if so where could the noise be coming from?