I need help troubleshooting a speaker issue with my Sony STR-D315. The Left speakers in both the A and B channels don't seem to be working properly. The facts: [*]A speakers = 8Ω [*]B speakers = 4Ω (I know, I'm playing with fire) [*]When only one channel is selected (either A or B), the left speaker on that channel produces sound, but so much quieter than the right, it's imperceptible unless the balance is all the way left. [*]When both channels are selected, neither of the left speakers produce sound. [*]It happens throughout all modes. [*]The balance is adjusted properly. [*]Muting is off. [*]The manual indicates that it was designed to play both channels simultaneously. [*]I opened it up and vacuumed out the fuzzballs. [/list] Any thoughts?