As you can see, the number of people with the same issue is very high, for sure Samsung team knows about the firmware upgrade risks, seems that they are just hidding it and pretending to be surprise when we call.
In my case I had a repair technician replace the power supply. You should not pay more then $150 for parts and labor. Although it was Samsung's faulty firmware update it paid $0. I do not trust Samsung. And will never buy or recommend their products.
Don’t perform a software update for your @SamsungUS tv it will damage the control board. I finally fixed mine at over $150 + inconvenience. @SamsungSupport. My previous reply stated that it was the power supply. Correction it was the control board.
Thanks for the warning, but unfortunately I discovered it too late.
My hypothesis is that the new firmwares changes some of the internal voltages or signal frequencies of the mother boards, it causes several failures, as we can see here. Seems that thee engineering team didn't perceive this risk or the quality of the componets used by samsung is very poor.
Clearly it's a project failure. As soon as I repair my TV, my intention is to compare the old board with the new one, identifing the problems and share it at youtube as Samsung is not giving any clarification about it.
Let's see if I can help someone.