1, after the liquid crystal power supply, the auxiliary power supply, the output +5V voltage to the digital board CPU, this time the whole machine is in standby state. When according to the standby key, the CPU outputs start level, the PFC circuit to work, will be converted into normal DC voltage (+380V) +300V pulsating DC voltage, then main switching power supply of pulse oscillator only began to work, then the main switching transformer secondary output 12V, 24V voltage, the machine into

Normal working condition.

2, what is the PFC circuit? White is the +300V PFC circuit voltage bridge rectifier after the rise to +375V----+400V. Which is LCD TV power supply and CRT TV power differs from that of the first point, second point of difference is the secondary voltage than the CRT low and elsewhere and ordinary switch power supply on the same principle. Measured a large filter capacitor 330U/450V voltage at both ends of the +375V---+400V indicates power factor correction circuit is normal; if the measured voltage across the capacitor +300V that PFC circuit does not work and check of PFC oscillator integrated circuit.