DIAGNOSIS
HDMI-CEC (Consumer Electronics Control) is disabled or malfunctioning. This feature is required for power and volume syncing.
FIX
1. Enable Anynet+ (HDMI-CEC) on your Samsung TV. Navigate to Settings -> Connection -> External Device Manager -> Anynet+ (HDMI-CEC) and turn it ON.
2. Enable 'Auto Power Link' on the soundbar. Using the soundbar remote, press and hold the 'Gear' icon button to enter settings. Navigate to 'Function' and set 'Auto Power Link' to ON.
3. Power cycle both devices. Unplug both the TV and soundbar from the wall for 2 minutes to clear the CEC handshake cache.
IF THAT DIDN'T WORK
Try a different HDMI port on the TV. Use the HDMI port labeled 'eARC/ARC'. Some TVs only support CEC on specific ports. Consult your TV manual.
HEADS UP
If you have other devices in the chain (e.g., a cable box, game console), they can interfere with CEC signals. Simplify the connection by plugging sources directly into the soundbar's HDMI inputs instead of the TV.