Why does my TV backlight randomly turn off?

TV model: Toshiba 58L4300U

Everything in the TV works. When the backlight turns off, the LCD still shows a picture and I confirmed this by using the flashlight test. The audio also works and the main TV motherboard shows a green LED confirming that it is on.

I am 99% sure that the problem is with the LED strips. I measured the voltage of the pins on the motherboard connector. There were five sets of anodes and cathodes. set 2 - 5 showed 48 volts but set 1 showed 41 volts. I thought that one LED was burned out on strip 1 but when I disassembled the screen, all LEDs were glowing.

Even weirder, LED strip 5 had an LED occasionally burn out but when I took a picture of it on my phone, everything was glowing!

Also, when the LEDs are on, there is a slight buzzing sound coming from the power board. I do not know if this is normal but is was very quite.