Samsung QN95D Neo QLED 4K TV screen flickers, flashes or goes black intermittently

The checks in more detail

If it appears on one input, test another HDMI cable and port, since a cable that cannot carry the signal causes flicker and dropouts. Check picture features that change brightness automatically. Turn off Ambient Light Detection, Eco Sensor and any adaptive brightness settings, and Energy Saving. Set Brightness manually, and pick a picture mode such as Movie or Standard. Reset the picture settings to default and test again. If the flicker appears only with certain content, such as a streaming film in a dark scene, it may be an effect of the content's compression and appear on other TVs.

Update the TV in Settings, Support, Software Update, since Samsung issues fixes for picture behavior. Power cycle the TV by unplugging it for a minute. Check that the TV is not set to an input mode that the signal does not match: HDMI UHD Color, or Input Signal Plus, on the port in use, should match the device's capability. If the flicker appears across the whole screen all the time, including the menus and on every input with a good signal, the backlight or panel may need service; contact Samsung with the model and serial number. Do not use damaged cables or poor extenders, and avoid placing the TV where its air vents are blocked.

If the flicker is a flash or a blink at the moment the picture changes, it may be the TV adjusting its backlight to the content, which Samsung calls Contrast Enhancer or Auto Local Dimming. Turn Contrast Enhancer off in Expert Settings as a test. Keep a short video of the flicker on your phone, taken with the screen in a dark room and the phone steady, because Samsung support can use it. Place the TV where the vents are free and the room is not very hot, since heat stresses a mini-LED backlight and can aggravate odd brightness behavior.