Hitachi LCD TV 32LD390TC normally starts backlighting after 20 seconds or so, no backlight common problem - android - Phones Developers

Photocoupler

Hitachi 32LD390TC, normal startup backlight after 20 seconds or so, no backlight common problem, faulty component R545, R549 resistance color... 24v will be turned on after the relay is directly connected, because the voltage will fluctuate for 24 seconds to 25.3v without load Until 24v connected to a 40w bulb voltage stability, this shows that the optocoupler voltage regulator circuit is normal, the fault is the power ic peripheral components, after the ratification of r549 deterioration, because the road is afraid of inaccuracy, welding a foot test To orange white gold, the color of the component is marked brown black brown gold, look at the 5v standby ic also has a touch of the same resistance is also brown black brown to brown orange brown, replace these two resistors ok, faulty components R549, R545 When the resistance becomes larger, the ic voltage becomes larger, and the output of the internal ic circuit is not normal, which causes the high voltage board to be very difficult, and the transformer is called, and the wattage is insufficient, which may cause such a situation.