Hi - I’ve just invested in a Sonos Beam and am unable to get a connection using the HDMI Arc socket on my Panasonic TX-40DX700 - launched in 2016. Following advice from other posters I have:

disconnected all other HDMI leads from the TV

unplugged both TV and Beam for five minutes

checked cable is secure both ends

ensured that I connected using the correct HDMI socket (middle of three)

only connected the cable when the TV was switched on (when I do this the tv sound is muted)

set the Viera Link to ‘on’ in settings on the TV

set TV sound to Home Cinema

Whenever I use the Sonos app to link the TV to the Beam I get the following message ‘HDMI ARC not detected. Make sure the HDMI cable is connected to the ARC port and your TV is on’. 

To check that the Beam was working I connected up using the optical lead. Immediately the TV’s sound came out of both the Beam and the TV. I tried to change the sound setting on the TV to Home Cinema rather than TV but that option was unavailable.

I’m starting to run out of options - does anyone have a suggestion that might help?