@svetiduje
Not all 6x0 series versions have FM transmitter functions, but i thought all 660s have it though.

Did you do a reset as dasilvarsa suggested in post #4? I haven't seen in any later replies of yours that you did that. From memory all 600s have a reset button under the lift-up antenna. Do that with the power disconnected from external power, then reconnect to power holding the lower RH corner of the screen as it turns on to fully reset it to factory defaults, but backup your favourites etc first of course.