PLX 500 loud buzzing from time to time

HI!

Since yesterday I have a strange problem with my PLX 500 connected to the DJM 250 mk2 (with recordbox)
I get a loud buzzing from time to time. 
It doesn't always happen. Nor can I say when. Has anyone heard such a sound before?

You can here it here at 11 second:

https://soundcloud.com/tlg-music/buzz/s-noBrddoGycx?utm_source=clipboard&utm_medium=text&utm_campaign=social_sharing