Hello, I recently did a full Leestereo style recap and upgrade on a friends AU-717. He's telling me that now the right channel occasionally drops out, and now when it is working it has less bass than the left. After he turns it on/off a few times the channel comes back. I'm curious as to whats going on here, any obvious place to start? I know he's had some issues with the switch on the back causing problems (the preamp bypass switch). I'm thinking of looking at that first as the potential culprit.