I had this same issue with a V240HC with a broken plug inside the Input jack. I guess the computer got confused on the state of the plug and it was stuck in "Phones" mode.
This fixed the problem.
Plug-in jack 1/4 on your v 120.
Invoke firmware settings by holding “Home” button
Change “Phones Mode” option from Phones to Line.
Thanks for the help and saving a call to support