I received my Axe FX II back from Fractal repair last week and after playing through several presets I found that there are several amp models that do not have output. I have tried all of the usual troubleshooting steps for this, and my settings all seem to look good. I do have sound on these presets when I bypass the amp block, which leads me to believe that I have definitely narrowed down the problem to the amps. I have also tried to start from scratch and build a preset using the problem amp models, and I still experience no sound output at all. I have reset the SRAM and reinstalled the firmware and presets. Any ideas on what could cause this issue?