Elsewhere I read
"To further disassemble the unit, you have to remove the mesh screen on
the back side of the unit, then you can access the screws that hold the
two halves of the donut together. I was able to do that by prying on the
bottom edge with a knife. The screen is glued in place and has some
little tabs as well."
I think I can interpret what that means, and will reattack later today