Hori EX2 Control Pad

Got a bit of a dilemma with my hori ex2 control pad, all of a sudden its not responding properly. Even though the d-pad and the analog stick are in neutral the pad is always holding down. If I press up on the d-pad it moves to the left and if I press right its moves to the upper left.

From the outside every thing looks normal and there are no rattling noises when I shake the pad.

I wanna open it up, but im not sure what to look for as to what could be causing the problem, if anybody can advise me I’d be grateful

Thanks