TCL-L46E78F LCD TV red light is not turned on - android - Phones Developers

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TCL-L46E78F LCD TV red light is not turned on Check the power board STB = 5V, 24V, 12V, 5V all without voltage.
The power board is connected to the dummy load. After the STB5V is connected to the PS-ON/OFF terminal with a 4.7K resistor, 24V, 12V, and 5V are normal.
It seems to be a problem with the motherboard. Check the five elements of the CPU: one: power supply, two: reset, three: crystal, four: bus voltage, five: working program memory (FLASH) U13.
One, two, three, four are no problem, five: U13 power supply is wrong. Look at the picture
The number U13 of 7,13 feet = 0.8V (normal 3.3V). The U13 power supply DC-DC block U25 input 5V, output = 0.8V, check C249 no problem, check CA76 is bad.
For CA76, U13's 7,8 feet = 3.3V is normal, but U13 other feet = 0V, suspect U13 is bad, press U13 after pressing the power button, first red light, then green light, everything is normal.