So far, the suspected cause instant boot standby power overload current protection. To quickly determine fault, disconnect the remote control receiver terminals E1, repeated power test, the fault no longer occurs. Consider CPU or remote control receiver operating current increases, but the function is not affected. The cathode of the diode D1118 connected resistors R1175 access after disconnecting the positive D1118 (see the dashed box), power remote receiver is changed directly from the switching power supply. Access E1 terminals, power test, fault no longer occurs, but the TV lost power standby mode function.rHQservice manual download site

    Although failure ruled out, but do not always feel perfect, after all, a TV missing boot function in the standby mode. The same model because there is no replacement parts, trying to restore this functionality through other means, from the over-current protection circuit sampling resistor values, the maximum output current standby power of only 10.7mA, consider the machine boot properly sometimes, and sometimes not boot, and fault persists more than two months, indicating that the overcurrent protection circuit is in critical working condition, and more stable. Thus, the decision to increase the standby power supply output current, the sampling resistor R815 (56Ω) replaced 51Ω, the output current increases to 11.8mA, restore the connection R1175 and circuit switched after repeated testing, fault no longer occurs.rHQservice manual download site

   Summary: analysis of the mechanism of failure as follows. Since CPu or remote control receiver operating current increases, the moment when the CPU 6-pin output current, standby power supply output current reaches the maximum voltage drop at both ends of the sampling resistor R815 reaches 0.6V, Q812 turns on, Q810 emitter current weakened, then the CPU 39 feet voltage drop moment, its 6-foot voltage disappears, Q812 Q810 emitter current is reduced due to the cut-off. Q810 is turned on again when the power supply for the CPU, because the P5 S801 instant contact does not automatically close, CPU does not receive the signal and power in standby mode, the quiescent current is small because, again, the overcurrent protection circuit is not action, there has been an instant boot standby light and dark flashes lit a few changes to the symptom.

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