brand new JP15 – middle and neck position ist not working !

just received my brand new JP15 (flame teal) and I´m a bit disappointed, because the middle and neck position of the pick ups is not working ! In high gain mode, there is only a quite noise and hiss. Sounds like a battery is dying…
Bridge an piezo is working fine. And I´ve already changed the battery .
Do I miss something ?

Cheers,

Michael