I just replaced the logic board in my 12" PBG4 and now whenever the fan comes on, I can hear it in the right channel of my headphones. I checked to see if any wires are overlapping, but nothing seemed out of place. Admittedly, I don't know if all the wires layed down exactly where they were before I took the thing apart. Any ideas for getting rid of that sound? Other than that "annoyance", everything is working fine.