Skyworth LCD TV 32E55HM second repair machine multi-fault repair experience - android - Phones Developers

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Receive a Skyworth LCD TV 32E55HM failure phenomenon three no, the indicator light is not bright, because the most faulty of this machine is the backlight is dark, you can change the booster tube, when you first see the warranty sticker has been opened, know that it must be repaired, fear is The problem with the screen, there are hands and feet, and finally decided to gamble,
Enter the topic, disassemble, detect no 5VS, 12, 24v are not, remove the board, when the power board is reversed, it is found that it has been repaired, and the switch tube 10N60 three feet are suspended, the tube has penetrated D201 and D202 have been broken down, replaced, and other components are not damaged. The switch tube is replaced by 13N60. The power supply voltage is coming out, but the power supply has noise. It is judged that the pipe parameters are not matched. Find a new 10N60 pipe and install it. Powered up, a loud noise, scared me, a leg of the pipe exploded, this is a change of the tube, after rubbing the motherboard, [attachimg]49347, I don't know why, the pipe is new, and there is no short circuit. The next test ZD202.ZD205, R213, fuse and switch tube are all killed. The board is blackened. After the new switch, the switch tube is 20n60, the voltage is coming out, it is very quiet, the power supply is red, and it is a hilarious surprise. Then unexpected things happen. How to press it is not turned on, but sometimes the red light is Will flash green light, and finally observe, the red light will change green light for six seconds and then continue red light, cycle, measure the motherboard voltage, U13, 2.6V. U10 2.6V .U12 3.3V. U10 voltage will turn green when Dropped to 2.3v. CPU fever but not hot, using the formula of 8117 to calculate the U13 2.6V is normal, U10 is not normal should be 1.2V, the power is off the resistance value, the actual measurement U13 20 Euro, U108 Europe U12 and U10 There is only a resistance of 2 ohms between them, and the power supply tube is removed without change. Finally, the CPU is judged to be bad, and the resistance value is restored to normal. Arrived three days after the order, put on, the red light is on, the power is turned on, the green light is turned on, the screen is powered off at the moment of the light, and then restarted repeatedly, this is depressed, there are still problems. Remove the backlight line and hear the sound of the boot. The backlight is a group of five lamps connected in parallel. A group can be lit and can be seen. The screen display is normal. It seems that the boost is not a problem with the backlight. After the test, the two groups can be normal, and the three groups are shut down. If it is suspected to be a light strip, it will open. Just the back of the backlight board has a rubbing object, and it is normal to find everything, and the next time is really depressing.
The test found that when power was lost, 5V, 12V, 24V were all dropped, suspected to be overvoltage protection, or with no load, detected overvoltage protection, disconnected overvoltage circuit, and the voltage was normal. , replaced 817, 431, No results, finally replaced TEA1733P, even more fruitless, to this is crazy, I want to buy a power board, but I just want to know where the problem, continue to repair, check the peripheral circuit of the power chip, no The problem, check the Q304 intact, replace the switch tube, or useless, my heart is annoying, do not engage, have been looking at the drawings, look at the backlight part, because the backlight can light two, and stable, power down is also off All the voltage, so judge the backlight circuit is no problem, continue to observe the power supply part, suddenly noticed the insurance resistance of the switch tube, looking for a bad look is 0.18, and I changed to a 0.39, will it be it The problem, it used to be such a change is almost no problem, rummaging to find a 0.18, put on, the artifact happened, it is normal, the backlight is all lit and not powered down, the machine is finally repaired. At the end of the test, I found that AV2 is not easy to use, the image is whitish, AV1 is normal, I have observed the interface, I have a lot of thoughts, why is it bad CPU, the interface resistance is obviously black, this machine may be a lightning strike machine, go home The repair found that it was much worse, and said that it could not be repaired. Finally the user sold the scrap. Finally, look at all the warriors who died.
Actually, this TV has been repaired intermittently for several days. In the middle, because the wife gave birth to a big fat son and did not open the door for several days, the fault is not complicated, but it is not noticed in one aspect, but also inexperienced. I hope my friends will come across similar ones.