Samsung 4k tv. UN65ks8000. No picture I think the led strip screwless back off, having trouble getting the trim ring off to remove front screen. does it snap off??? dont want to crack the screen

I think an LED problem is more likely. The LED strips are usually powered by a driver circuit on the power supply board. You can check this with a bright flashlight shining on the front of the display at about a 20° angle from parallel to the display. If you can see the picture or the menu with the flashlight beam during the "dark" period, the problem is NOT likely to be the T-Con board.

You can also look at the back of the set with the cover removed - most sets have a number of vent holes in the back plate through which the backlight can be seen when it is on. If these holes go dark when the TV goes black, the backlight is being turned off.

When the screen is lit, take a picture quickly and look for dark spots. Maybe one of the LEDs has a partial short that shuts down the LED power and triggers a retry cycle. If so, after a while it will burn out and then the entire LED strip will be inoperative.

Test the LED strips with a variable power supply to the specified voltage. Test the voltage output to them with a multimeter.

But this is the usual outcome. At least you have a picture.

https://www.fixya.com/support/r29790007-repairing_own_television

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There is no way to know for sure without taking it apart, but chances are its bad lamp strips, I'd say 9 out of 10 chance of lamps

If you turn on your TV and you have sound but no picture, our LED back light might not be working. get a flash light. Hold the flash light up to the screen. If you see movement your LED back lights aren't working.

In most of the case, the back lights LED strips have defective LED diode on it.

I will test the back lights first.

To test the back lights, you need to disconnect the cable between the main power supply & the main board, disassembly the display panel, expose the LED back lights portion, then apply the AC power to the power supply, the back lights should light up, and you will see the defective ones.

If you see any LED is not light up, replace the strip.

Please replace all of the LED back lights strips.

Yes. You can set it as your viewing interest. Electro help