Technical Problem on my mpc 2000xl,help needed

when i was on my mpc the other day, i made a couple of sequences,but all of a sudden it was as if my mpc froze or something,i was pressing pads,and no sound was there, no sequence would play, in the end they came back,but dont know why it did it, any ideas?

mine freezes from time to time when i'm making alot of quick button pushes. it usually last about 20 seconds or so. sometimes if i hit the shift/load or shift/save buttons it will come back quicker. it doesn't happen too often and only seems to do it when i'm flyin' through from screen to screen or pushing multiple buttons right after each other.