sony wh-1000xm4 right side not working but battery fully charged

Hi all,

after a long time i wanted to use my headphones with a new mobile phone. I was able to load them with the USB cable with came in the package but the right side gives no sound. I tried a factory in reset, update and disconnecting the battery and connecting it again. Is there anything else i can try or connections i can check? I know how to use a soldering iron but cannot find anything strange on the board.

Should i also check the mother board left side?