You could but it would be a lot easier to replace it with a PY3 board. Oh and don’t get a PY4 either, that’s the new version of the PY2 for a DMC. The PY3 is the newest version for the TAC20. To use a PA6 board you’d have to order all 5 screw terminal plugs for it, a digital encoder, delete the rectifier, and change D12/13 from 1 to 8 in the controller.
