XDJ-RX2 Burning smells when is switch off!

Hello!
Is that normal when is plugged in my item , Pioneer XDJ-RX2 , and nothing working, does not switch on , and still burnt smells mostly ,around jog wheels!?
I have a dustcover as well , and Im using not too often, about 1-2 times / week !?  
When its working, everything fine I think, its just weird when not work, and a burnt smell come.
Thank you !! 
Best regards!
Balázs