No sound coming out or in the MPC2000

Hello
I am not getting in sound coming out or into my MPC2000
I tired to sample a synth I have and it doesn't even move the meter

The only time the meter moves in sample move is when I move the volume knob
when I move the knob I get a cracking noise.

Any help would be great
Thanks

Might need to clean the volume knob with deoxit or something similar.

yeah sounds like deoxit could solve the problem if not it could just be so dirty that you could buy a replacement board for the input and monitor pots.