I hath the same issue and it started in November 2018 I bought the 65Q9fn in September I was shocked for such expensive tv 2 months old Price $3600 they sent a service guy from Samsung, said it is a broken wire in the Glass Fiber Cable hey replaced
the Glass Fiber Cable and everything is working normal ,hey gave me advice Do not roll too tightly the Glass Fiber Cable leave 8 Centimeters space when you roll up the Glass Fiber Cable hey said also there are 8 wires in the Glass Fiber Cable thinner as a hair and they break easily,many people Roll it to tightly or let the Coiled Cable hanging from the ground when they wall mounted the tv because of that 1 or 2 of the 8 wires break hey said also the most commenly caused issues is the is the Glass Fiber Cable or the One Connect Box ,hey said also Qleds are the best tv's from Samsung.
I hope you can enjoy your tv soon.
Same problem here. his is not fixed. Be ware of the stalling tactic - they try to ware you down and ultimately promise a service call. I have read in several places on the web that the fix that the service folks make doesn't work and they have to start all over again with the support nightmare call system. Support does not respond and when they do it takes weeks to come to your house -in my case they never actually made it. When you buy something this expensive, they should send you a new one. My TV hasn't worked in over a month. I have made 14 calls to Samsung and scheduled 2 appointments under different cases for this problem and the service person did not show up. Support in the Philippines promised 3 times to call me, we set up a time and they never called. I have recorded each call and I am preparing a small video to post on the web so consumers are wise to this company's practice of not standing behind their products. I will edit and add them to the video I am making. When I am done I will let you know and we can post this together on FB, Twitter, etc. Also, if you are unlucky enough to be in the hospital, make sure that you check to see if a doc relied on an image created by Samsung. I found a huge error in their software which is not surprising considering BIXBY ;-). Lets hold them accountable!!!