Screen "glows" but no video/picture and audio works

I have a Samsung UN46H5203AFXZA that the picture/video has recently totally gone out. It has done this before and I was always able to power it on a while (with blank screen AUDIO working), then power it off for a second and power back on and “SMART TV” came up and it worked and everything was fine. It was almost as if something needed to “warm up” before and the picture would be fine after leaving it on in the blank state, audio working, and powering off then right back on. It has done this for over a year, turn TV on initially, have audio and glowing screen, let it stay for 5, 10, 15 minutes, power off then immediately power on and it was fine all night or day.

Anyhow, now it is totally blank and the audio is still working because i can change channels on the cable box and hear it, as before. However now, after leaving it on for a while, I can turn it off and it stays blank or “glowing” black in no light. I have tried “flashlight” method and don’t see anything and in a totally dark room, all lights off, the screen does glow black. After everything I’ve read if I’m reading correctly, this means my LED backlights ARE working right?

Please advise as I do not have the money for a new TV. I have my own hand tools and a couple of multimeters so I know my way around A LITTLE on electronics. I have not removed any panels yet.