pioneer ddj400 crackling interference and speed issues

Hi, my pioneer ddj400 randomly crackles during mixing and recently the track speed changes by its self. During my last mix (just now) the crackling apears through the main output and headphones, its lasts for around 2 to 6 seconds. Yesterday and this morning i noticed the speed of the track changing to the point it was running at 130bpm and all by it self on both decks went down to 109bpm. I have a gig on saturday so if anyone can help it would be very helpful. thank you