Jerome - I purchased an e900 75 in November 2017. The ARC/HDMI connection with a HEOS Home Cinema soundbar worked for about 6 weeks and then crashed. I have attempted all of your suggested fix’s and cannot establish a connection with the sound bar when powering up the TV. Changing the sound output back to “TV Speakers” will result in sound from the TV. The only fix that works for me is a Restart from the About Setting, the sound will remain on the sound bar (all inputs, and apps) until the TV is powered off. Note - the TV always auto detects the sound bar at power up and Restart and will switch to “Audio System”, if needed. When will Sony upgrade the software to correct this ARC issue?