Model: QN75Q9FNA
Problem: When using an external source (like hdmi) other than the native samsung smart tv interface (built in apps), tv behaves completely unpredictably. It will work flawlessly, for months, then it will be unusable, turning image on and off with visual and audio distortion (black screen, samsung circle appears, glitches, etc).
Mitigations: Changed One Connect Cable, factory reset TV, power cycled all devices, switched hmdi ports and cables, routed sources from receiver to directly attach to one connect box.
Solutions: Sometimes unplugging and replugging in hdmi solves problem temporarily. Unplugging and replugging TV can solve problem temporarily. Replacing One Connect cable solved problem for several months once.
Note: Thank you for your help with this!
