Hi,

Have you verified that it is not just the output cable from the adapter that is faulty, e.g. fractured wiring in cable?

Open the adapter and then prove continuity in the cable wiring from the adapter circuit board to the cable plug.

If the cable is OK then check that the wiring from the adapter power input pins to the motherboard is OK.

After that visually inspect for any obviously damaged components.

If all appears to be OK visually, then you will have to do point to point testing with a DMM (digital multimeter) to find out where the problem is.

I been having same problem except my lower bulbs on screen have gotten to 118 degrees so I have big concerns of fire!!!

Plus tv just crashes then goes into reboot mode at times can’t turn on or off and Samsung has no answer and dealer has no answer.

So I been going in basement where my box (black) is unplugged tv wake a minute plug back in and good for who knows maybe 1/2 movie or 1 quarter of football game

This tv has a wire similar to a guitar string feed through the wall into basement black box.

So my only solution at this time is a FAN on tv when watching tv this way it cooling the led bulbs. Plus I missed extended warranty by few months!!!

Samsung said they will give me $100.00 off a new tv THEY ARE SO KIND N O T !!! I’m done with Samsung

But here’s my model number: QN 55Q7FNA