I've managed to fix the amp in the ADA995 when I blew the rear channel amp. There is a design fault with the voltage regulator that causes it to run very hot, which frys the plastic housing glued near it, which corrodes the circuit board trace.
Getting the sub/amp apart is a b*tch. But doable. You need to not only remove the screws in the back under the flat grills, but ALSO 3 screws behind the top speaker that also hold the amp in place. And getting the power supply out is another rather difficult procedure, which is needed if you want to run the amp on the bench to troubleshoot.
How did you get at the 3 screws behind the top speaker? Did you ever get it fixed? If so, how?