my vizio soundbar m512a-h6 won't turn on with the tv anymore, have to use the remote every time

DIAGNOSIS The HDMI-CEC (aka Vizio 'EasyLink') control has been disabled or is glitching. This is the feature that syncs power states.

FIX Re-enable CEC control on both the soundbar and your TV.

1. On the soundbar remote, press and hold the 'Input' button for 5 seconds until the display shows 'CEC On'.
2. On your TV, navigate to the system settings (often under 'External Devices' or 'HDMI') and ensure CEC is enabled.
3. Power cycle both devices: unplug both TV and soundbar for 1 minute, plug TV in first, then soundbar.

IF THAT DIDN'T WORK The HDMI cable may not support CEC well. Try a different, newer high-speed HDMI cable between the TV's ARC/eARC port and the soundbar's HDMI OUT port.

HEADS UP If you have other CEC devices (like a game console), they can interfere. Try turning off CEC on other devices to see if the soundbar/TV link stabilizes.