I was readjusting my Onkyo AVR with the Audyssey mic last night. I had to adjust the volume to 75db with the volume knob on the back. When i went to adjust it the test tone would either cut out a bit (lowering the volume), act normal or double the output (like switching on a 12db boost), all from just touching the knob. The overall action of the volume knob still works fine. It lowers and raises the volume perfectly. But if I tapped the knob or touched it in a way, it would act up.
I got it dialed in and it works fine now. I played a BD afterwards with some powerful bass and it was fine. The volume knob worked fine while testing it out during the movie.
I have the LPF knob on LFE, normal phasing.