I have a 9 month old LG 4K Smart TV and a Sonos Beam (as well as a Cable TV Box). Everything was working great for the past 6 months (Sonos using HDMI ARC). Yesterday, we lost power for less than a minute and now the Sonos cannot maintain a connection to the TV. Specifically, when watching TV, the sound will come through the TV speakers, then switch to the Beam for a second or two, and then back to the TV. I checked all the TV settings and SIMPLINK is ON and whenever I try to set the Audio Out to HDMI ARC, it only stays set for a second or two and then automatically switches back to “Internal TV Speakers”. Tried rebooting Sonos several times as well as turning the TV ON/OFF.
Best answer by Airgetlam
Hmmm, most odd. Makes me wonder if there was a background update on the TV, or even another device that is connected to it with HDMI. It might be worth looking at each device other than the TV and turning off HDMI-CEC. But ultimately, I would recommend that you submit a system diagnostic within 10 minutes of experiencing this issue, and contact Sonos Support to discuss it.
I usually suggest the phone folks, they have more tools available, but are available Monday through Friday during business hours. Twitter support folks are available 24/7.
There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.