try cleaning the pots, there is some spray I bought at radio shack few years ago and fixed mine at the time. IN fact the can is right here in the cabinet, electrical cleaner , lubricant My x52 was spiking and acting up bad, I had bought another used pair at the time, then someone in the forums years ago was talking about cleaning the pots, so I tried it and the stick came back to life and worked just fine..
Now both pair sit in a box, maybe the interest will come back to use them one day.