Video battery doorbell not activating mechanical chime

Battery Video doorbell Gen 3 wont operate existing mechanical chime when operating with battery installed(hardwired to AC from previous doorbell).It works fine apart from this ( Motion detection, doorbell , video , links to alexa echo show etc.) .18v Ac supply verified.Reset to factory defaults more than once etc.Whats odd is that if i remove the battery from the Gen 3 and then press the doorbell the mechanical chime works.But then I don't have any ring application functionality as without the battery its a dumb terminal. Any ideas? All input appreciated. Ps. Some posts mention an in app option under device settings where you can select chime ( mechanical or electronic etc) . I cannot this. Has this option been removed?