I have a newly installed F90BT unit with the upgraded software and am experiencing a subtle high-pitched whine coming from the head unit, not from the speakers. This whine is noticeable whenever the unit is powered up and is not affected by any setting of the volume control, nor is it changed in any selection of the various inputs. Even when the unit is in the OFF setting (power still applied in accessory key position), the same sound is noted. I would say that this sound is similiar to a power supply charging noise.
Anyone else had this problem? All suggestions would be appreciated.
