MPC 2500 pads are not working

I have recently purchased an MPC 2500. I'm kind of new to MPC's and music production in general. I've tested all buttons on this MPC and I believe they all work besides the pads. I try using the mode button and it flashes but when I hit the any of the 16 pads nothing happens. I was wondering if anyone could possibly help me? I would greatly appreciate it. Thank you.

crack it open, track bac the connector make sure it's all plugged in tight