I. like most, have been having intermittent problems linking (via ARC) a Samsung 5.1 system to my QE65Q7FAM since I bought the TV a couple of years ago. I've spent hours trying different 'fixes' unsuccessfully and also tried the Samsung 'help line' - not so helpful! Then by chance came across a suggestion of deactivating UHD colour on the ARC HDMI port in TV settings. Give it a try - it worked for me .... Good Luck!
