Thank you oldturkey03. I had tried your sequence and no joy at this end. I installed a temporary 65" Samsung mainboard...

oldturkey03, You were spectacular with your expertease on ealier problem of mine, hoping you might help with an answer to...

Samsung un65au8000f" No power -No Start with a Bn4401111A power board. No power indicator light. Upon powering and...

Basically same problem! Samsung Qn70Q6DTAF. I disconnected short ribbon cables at base of TV. (SFPCX695G-008) and cleaned. I now have constant back light and sound, but no mage whatsoever. My post:: Update on QN70Q6DTAF Boot Loop Problem Possible answer If it is available! Hope this helps.

Hope this helps someone. It appears as though my power board was ok. My power button was inoperable. My back lights were partialy burnt out. Combined these left me with the thought that the power board was the culpert. I wish to thank oldturkey03 for for his input and thoughts. Much appreciated.