My new ADC would not remove the blue and orange fringes. After much googling I determined, as others have reported, that my ADC was mis-assembled.
There are two threaded holes in each prism, 180ยบ apart. Mine had the levers attached to the fat end of both prisms.
Careful examination of the inside, with both attachment ends removed, will show the slight taper in the round prism holder. One side fills the channel, the opposite only about half because of the prisms' taper.
The ring holding the bubble level was installed backwards too, so the offset bubble holder obstructed the outermost lever. With the levers removed to fix the prism problem, it was easy to reverse the ring, although the white set-screw is too large and bumps up against bumps the lever.
