i am on my 2nd cda-105 because i thought the other one was messing up, but this one is doing the same stuff. one problem in particular is the aux port on the back. i am talking about the small headphone jack, not the usb or other digital input. i went into the stereo settings and turned on all the inputs and this still doesn't work. i have tried 3 cables and 2 mp3 players that are known to work. now 2 alpine stereo's. am i missing something on the aux port? i turned on all inputs, tried one at a time, the gain is up, nothing works.