Same/similar problem TCL 49D100BAA (1080p no roku/no wifi) Tv hdmi(arc input) to rhe soundbar powerd woofer amplifier hdmi distribution (1 in hdmi from computer, 1 out hdmi <arc> to Tv) . Tv started slowly flashing dim to bright over ~5 min the rate went from 20x/min ro 60+/min. The solution working for me/my set uo so far. 1.Turned off tv, unplug hdmi and power cord. Push power button when unplugged, wait few min(i did 5 not ina hurry). 2. Plug just power cord back in Turn TV on goto Tv menu and factory reset (i restarted Tv again probably unnec) 3.. After restart the following settings worked(Bright:50 ; Contrast:55; Hue:55; Sharp:50; temp :normal; Dynamic Contrast:Off; screen ratio:Point ro Point; NR:Off. Backlight:50. 4. All cables checked and/or (re) connected to computer. So far sink remains open, no other problems.. Yet.