Novation Ultranova Rubber Buttons / Touch Knob Repair

I’m looking for spare rubber buttons for the Novation Ultranova analog-modeling synthesizer. Particularly an “ON” button and an “EDIT” button. In addition, I’m also wondering if there is a fix for a fidgety touch mode aspect of one of the top knobs. I’m guessing it’s either from oxidation or a loose connection. Thanks in advance