This sounds like a parallel case, and I'm wondering why you neglected to test the power supply:
I'll bet that if a speaker in a system quit playing, you'd try another speaker... and if that didn't work, instead of throwing out the first two, you'd test the amplifier.

One of the first things we do when troubleshooting is to divide the universe, that is, split the system in two and see if one or both halves are working. I wonder why you didn't test the power supply!