Using a multimeter I was able to ring out the encoder and It does function as expected.
The joystick functions up/down/left/right of the encoder work as expected. In the schematic, the only components in line with the encoder and the uPC are two surface mount transistors. These check out good, but could still be faulty. I also found a surface mount fuse that was open (not really part of the volume control circuit) but replacing it had no effect on volume control. I am still at it.