Hisense color TV does not boot a special failure example - Appliances

DFN1006 TP-RCLAMP3321P ESD Diode Low Capacitance

Filter 18.432M

A Hisense 25 machine, the model forgot, three no, the indication is not bright, the machine uses 9373 super chip, open the cover to check the power supply is basically normal, but the switching power supply 12V is a little lower. The 12V disconnected load returns to normal, so it seems that 12V may have a short circuit condition. Since there is no drawing data on the door repair, it is found through the triode that a 7808 and 7805 are respectively supplied to other parts, and the two voltage regulators are connected in series, so the output of the 7808 output is found to be only about 6V, and it is connected in series. Only 7805 has almost no voltage. When the 7805 is disconnected, 8V is normal. b connects the 7805 to the circuit. When the power is turned on, the radiator is inadvertently touched. It is very hot and the load is short-circuited. So the vines touched the vine, disconnected to a line in the direction of the 9373, and the voltage recovered. At this time, I felt awkward; 9373 would not be broken. So after the recovery, I found that the foot of the 9373 power supply was disconnected, or there was no voltage. I went along the line again. It took a lot of effort to find another way to the tuner. Is this the truth? Decisively disconnect the tuner power supply [5V power supply tuner], a voltage is still 0? No, so go to the crossover line of the tuner, the voltage is normal, there is only one electrolytic capacitor and two small ceramic capacitors from the crossover to the high frequency head, because the probability of breakdown of the ceramic is much smaller than Electrolytic capacitor [low voltage state will hardly break down], remove the electrolytic capacitor [16V/100UF] measurement to the truth - white, the capacitor has been broken down, and the circuit is restored. The grating finally appeared, and the test machine was normal after the replacement. There are many faults caused by capacitor damage, but generally on the power supply side, the filter capacitor damage is really rare next to the high frequency head. It is worth noting that it is easy to be ignored.