Samsung UN40EH5050F led backlight turn off after 1 min.

Hi there,

i have a Samsung UN40EH5050F led backlight Issue. I can see the picture with the flash light. The backlight will work for 1 minute when I hard reset the TV.

I checked the power supply and all components look normal, nothing burn or melted . I used the voltage meter and checked the 4 pins that supply the power to the led. They provided 206 voltages when led light on. 0 voltages when backlight shut off by itself after 1 minute. Anyone knows what’s cause this issue and components need to replace? Please see pictures below. Thank you in advance.

power supply:

red and black circle are the 4 pins where I tested for power to led backlight.