[ask] Logitech z906 analog input no sound

[senying]

hello..
i have a problem with my logitech z906 speaker system..
https://imgur.com/a/19FckvA
the one in red circle (jack 3,5mm and RCA) both doesn't work.. i tried different cables, still no sound at all .. but the digital ones works fine (tried it on the same pc, the settings in windows is properly configure)
i want to use the jack for my nintendo switch and the digital ones for my pc.. 

so, what do u guys think went broken ? can it get repair ? because when i google the pcb of z906 they're covered in black "glue" or something https://imgur.com/t/pcb/jpDZNYe
i'm afraid that even if i get it to a technician they can't repair it because of that black glue..

i've tried asking around my area, some says maybe the socket is broken, or the ic for the jack is broken, and the other guy i asked said that the internal preamp is broken..

 

so what do u guys think?
thanks