I have the exact same problem and this happened from one day to another without any accident whatsoever.
I've had it for just over 2 years working fine and never had any problems.
I just went to turn it on like always but no sound was heard on power up, though it still got connected by bluetooth.
I tried a factory reset and nothing changed.
Strange thing is that my warranty ended last month.
Smells like programmed obsolescence.
I'm calling them to ask them if this is a common problem.
Very disappointed!!!