Loss of bass djm250mk2

Whilst playing vinyl on my 1210'S (no serato etc) my djm250mk2 all of a sudden lost full bass but when I turn the bass eq knob it still works but theres no punch it sounds very weak, also when I turn the volume up quite high it makes the bass punch through and sounds as it should do then goes cuts back to sounding weak again without even touching it..its maybe under 12 month old and not used alot.. KIND REGARDS in advance for any help..