The machine does not control the total switch on the 220V, the main board has the power soft switch (touch by the health), press the power touch keys, the TV no response, can not boot. Power supply board without 220V switch TV, plug in plug of 220V power supply power supply board work, 5V output provides power to the mainboard, on-board microprocessor therefore work, drive panel lights glowed, tell user television standby state is normal. Now standby red light does not shine, there are two reasons: one is damage to the power supply board, no output 5V power supply power to the motherboard; one is damage to the motherboard microprocessor did not work, unable to drive the panel indicator light.

In order to judge whether the fault in the power supply board, or in the motherboard, it can be measured whether the power supply board is supplied to the 5V power supply. If the motherboard has 5V power supply, the power board is normal, the fault in the motherboard; otherwise, the fault in the power supply board.

Open the shell, insert the 220V power supply, power socket board p802 10 and 11 feet is provide 5V power supply and measuring the feet have a 5V supply to the motherboard. This shows that the power supply board is good. Motherboard to the panel on the remote control receiving plate socket is CN4, the foot is motherboard to remote control receiver board 5V power supply, if the foot not 5V, damage to the motherboard 5V power supply circuit. 5V normal, the 5V power supply circuit is normal, but it can not explain the normal in the motherboard. There are two LED indicator lights, one is green and the other is red. The two LED indicating lamp production in a pipe core, divided into three pins: one is red and green indicator lamp cathode public leading foot is CN4 of foot; foot is green luminous tubes of the cathode leads to the foot, feet are red luminous tubes of the cathode leads to the foot.

Measuring CN4 1 ~ 4 pin voltage, if is low, high and low level, motherboard is good; otherwise, indicating the motherboard is bad. After measurement, the CN4 of the foot voltage is low, and the main board is damaged, and the replacement of the main board is replaced.