The old BAD CAPS issue. But https://www.google.com/search?q=UN55JU650DFCZA gave ZERO hits so the model is not something I can look up.
If it is that issue, have it fixed before the failing power supply fails and destroys all the other boards in the set.
I have a Samsung UN55JU650DFCZA smart tv, 55" diagonal. Had this tv for over a year and recently started having problems when first turned on. When first turned on, it starts and seems fine: picture and sound is fine, local tv station comes on, NETFLEX banner comes across as usual. But within a minute, sound goes dead and screen goes black, except near the top left corner of the screen is a small screen about 8" diagonal, that shows a picture and sound of a local station (like picture-in-picture). At this point, I can't select anything. My only solution is to turn the tv off and back on again. Occasionally this process will repeat a second time, but usually everything seems to be back to operating normally. Any thoughts/suggestions?