Hi, I've purchased a HW v3.1 from someone and after installing I've found that the right channel emits a buzzing noise. Both while playing and when music is paused. I've verified that the ground is properly connected in the car and all soldering points are good, at least visually. The previous owner did not note any buzzing so I expect that this is a problem in the car. Does anyone have any experience with this and/or have suggestions on how to fix the problem? Thanks.