Samsung screen V4 power switch control circuit principle of work is as follows: when turn on the power switch, power standby circuit work first, the output voltage of 5V by 10 feet N8007 No. sent to the board for standby circuit is used. When the motherboard is normal, the motherboard will output a set of low level, through the N8007 no. of 8 feet [of], r720 and added to the Q715 B pole, the cut-off Q715, rising the gate voltage of the Q715 C, rising the gate voltage of the Q714 B, C polar voltage drop, Q155 saturated conduction, optocoupler with PC131S began to work. PC131S of the pin voltage drops, through the d132, R133 added to Q131 B pole, Q131 saturated conduction, in C pole 18V voltage, through the R201 to relay RL201S power supply, the relay, the power supply to the rectifier circuit.
VS voltage control circuit:
When the normal work of the logic board, logic board will through the N8008 No.9 foot [VS-ON] input a set of high level, through the r257 is added to the Q207 B to stop Q207, to PC202S does not work, in 4 feet RC202S No. will produce a high potential [8V], control IC103 No.5 feet; for d255 for by another road and d206 control IC203 feet. [4.2V] the IC203, voltage (VS).