Sony TA-AX44 problem - No sound from rear, noise from headphone

Hi,
i found on the streets (literally) a TA-AX44, it powers on but no sound comes out from the speakers.

Also a continuous noise comes out from the headphone plug.

What can it be? I already downloaded the service manual and i'm trying to figure out something.

I suspect the STK2240, i read online that they tend to fail often.

Can you help me? Thanks!