I have a new QN55Q8DAAFXZA 2021 QLED TV that has had a strange issue since it came out of the box.
I don't think I would exactly call it a flicker but more of a random change of brightness level on the screen. It mostly seems to go between what I will call a "bright setting" and a "less bright setting". The TV will go back and forth between these 2 very different brightness settings frequently right after the TV is powered on and less frequently after it has been on for a while.
The most bothersome part of the issue is that when it is in the "bright setting" the TV acts as if it has a loose or pinched cable (which it does not, externally anyway) because any little movement will make the screen flicker. The TV is currently on the stand on top of a cabinet. If you touch the cabinet (like reaching into the cabinet to get a DVD out) you can see the picture flicker every time you touch the cabinet. Even walking across the wood floor of our old house will transmit your footsteps to the TV picture. BUT, this sensitivity is not there when the picture is in the "less bright setting".
This issue happens whether the source is an internal app or the TV set top box, so I know it isn't related to HDMI cables. I have tried a firmware update from 1805 to 1904, resetting the picture settings, factory reset of the TV, turning of various features like Adaptive picture and Intelligent picture settings. I've tried different color temps, picture modes, and turning all smart/auto features off and still get the same result.
Of note, maybe, I did notice some of this "flickering" happening while I checked the power cord for tightness. Could it just be a bad power cord? I read in another thread on this site that picture brightness and flicker can be caused by grounding issues with the electrical circuit your TV is plugged into, or with other devices powered by the same circuit. My TV power cord has a 2 prong plug, meaning that there is no prong for the ground wire in a receptacle. If these units are really so sensitive to grounding issues, shouldn't have a 3 wire power cord with a 3 prong plug? What am I missing here?
