..well, not quite dead, the red LED power light is working just fine. As for sound, not a hint, not even a click when I unplug it. These speakers are hanging off a 3500, and I have swapped them over to prove its not the 3500 at fault.

Any ideas?

From the manual which is on site for silver and gold members.

If the leads are ok (check by swapping leads on the good speaker) then I suspect faulty relay RL1 on pcb 03