One of my rotary encoders on my Artist Mix Black is malfunctioning as well. The rotation and push down is OK, but it does not sense the touch of my finger, so it will not pan anymore.
I opened up the mixer, but found that I have to solder out the encoder to see what type it is. The encoder has 2 wires on top, 3 wires on bottom and 2 large ground tabs on the sides. I'm kind of reluctant to do this before I know I can get a replacement.
(There are 4 ground tabs to unsolder to get behind a metal shielding that covers the front, other that that it was just torx and phillips screws to open the Artist Mix)
Front of encoder:
Back of encoder, with markings to what I have to unsolder
Front of the Artist Mix:
Back of the Artist Mix:
Another view of the encoder:
