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LS4service manual download site
LS4service manual download site
Nine, the Lord of switch power supply voltage: D810 output voltage 24 v, add to IC811 1 foot, IC811 is partial pressure sampling and error amplifier IC. Control voltage output terminal 2 feet light coupling PC841 luminous intensity of the inner glow pipe. When the 24 v switching power supply output voltage rises, IC811 2 feet of the voltage drop, light coupling inner glow tube light stronger, photosensitive resistance decreases, photosensitive tube E higher output voltage, IC830:6 feet higher voltage, control switch tube conduction narrow width, 24 v output stable. D832, R832, R831, C831 absorption peak voltage is primary coil circuit, when the switch tube by conduction suddenly turned into a globe, primary coil produces high peak voltage and breakdown within the IC will switch tube, increase the peak absorption circuit, can avoid this problem. LS4service manual download site
LS4service manual download site
Nine, the Lord of switch power supply switch control circuit: from A board CPU power on command: SUBON high level, to Q822 B, Q822 - Q820 conduction, then power relay RL801 lines) and the 5 v voltage, and off line package, two contact closure, 220 v, 220 v mains, added to the rectifier bridge, the main switch power began to work. Main switch power supply is working, IC830 4 feet voltage: 20 v. 6 feet: 1.4 V7:1.4 the V5:0.07 V. IC811 1 foot: 24 v2 feet: 22 v. LS4service manual download site
LS4service manual download site
Ten, power plate separate maintenance: when the event of A failure of the television, it is possible that the mainboard is A bad board, it is possible that bad P board or power board. Some soft fault it is difficult to tell which board is caused not work properly. For this, it is necessary to separate detection power panel, the P plate removed from the machine, add 220 v power supply to P plate separately, and the 24 v power supply output plug in dummy load 100 w bulb, if after startup, P plate output of each power supply voltage is normal, it P board is good, the fault is caused by A plate. Setting method is as follows: the P3 12 feet and 13 feet indirectly a 5 k resistor, the P1 connected to 220 v mains. Power panel in standby power supply and the main switch power supply can enter the work state at the same time. The measurement of P2, P3, each pin output voltage is normal.
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