A. your contacts inside the arms are dirty, a lot of DJ's like to lick the needle pins before putting them on the arm, this is not a smart. Causes the pins to runs inside the arm. The q-tip and some contact cleaner or alcohol and clean the inside pins ir use the eraser of a # 2 pencil and spin it inside the arm pins. This will remove any rust, gunk or other decay from the pins. Trust me, I have to do this every weekend @ the club B. Your RCA's are going bad from pulling them off the mixer wrong. very typical