Loose uneven Wheel

So, I gotta hand it to AKAI, the MPC500 is definitely road worthy- it takes some abuse
It has survived throughout the years but lately the little wheel is a tad uneven, and when I try to start spinning it fast it simply doesnt always "catch" and just spins with no effect. I have opened up my MPC before. How do I fix this?

hey wsup bro, you may have to replace the knob or the part that connects to the knob.

http://www.mpcstuff.com/1apt151060801.html