I posted on this a few months ago... Thanks to the good folks on this board, I found the DeOxit solution. After removing the 10 screws (at least 2 too many) the rest was simple and the full volume control, crackle-free sound, and quality audio was restored -- for a while.
After about a month left on the same volume, I tried the Volume knob again. This time, no response at all. The sound is okay, but stuck at a set volume. I have to use the OS and application volume controls to set volumes. This is probably okay too, but WTF? The Bass knob has also failed entirely.
I will probably try the DeOxit again, but at this point I've lost all enthusiam. These speakers are still less than a year old. The speed at which they failed, the breadth of the known problem, and the poor company response are all things I've chalked up to experience. I'm too busy to play with them any more and will likely toss them for a new, different brand. These speakers seemed too good to be true for their price point and they were.