Changhong plasma TV 3D42A3700I does not shine fault repair - Home Appliances

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One day, a middle-aged woman enters the store to ask if she can repair the LCD TV. Ask the size, 曰42.遂 起 维修 维修 维修 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42 He readily accepted, saying that the front section had found someone to change the board, it was more than 900, and only the machine was included. I was secretly horrified (I don’t know if the local maintenance fee has risen so high? Later...). Appointed time to go to the door, at first glance, the TV screen is vaguely white, it is estimated that there is fraud, look at the back, it really is plasma, non-liquid crystal! I haven't repaired the plasma, I don't know anything, but I don't have to pay so much for maintenance. When the power-on indicator flashes a few times, it will be extinguished, and then there will be no response. She said that the front section can still be turned on occasionally. Later, people have been demolished several times, and now they will not light up directly. Unpacking the preliminary inspection, there are no traces of repairs, and the motherboard is suspected to be bad. Tell the towed back to the store for repairs. If you can't fix the change, you have to increase the price.
Dragged back to the store, check the information on the Internet, who knows that the plasma data is surprisingly small. The screen is Samsung's S43AX-YB01\YD01, and the self-test method of the screen was not found in the life and death. According to several types of tests that were searched, there was no success. Measuring the power board standby 5VSB jitter, the motherboard can send a normal boot signal, the voltage output of each channel is also basically normal, but the instantaneous VS, VA voltage is reduced from the normal value to close to 0, PS-ON turned to high standby. Forced boot is also invalid. Repeatedly unplugging each line to turn on the power, can not light the screen. After unplugging some of the cables, the VS voltage will not go up. When the power-on test machine was turned on, the Y-plate screw was not on, and only heard a "click" sound, and it was broken. The measurement VSVA has become O, and the measurement Y board has found that one IGBT has been short-circuited, and several O-ohm fuses open. Due to the jitter of the power board 5VSB, it is suspected that the power board is problematic, and the power board alone was not successful. The online power-up board is said to be a modified version. I went to the same place to get the old Y board and removed an IGBT. I installed the test machine or did not light the screen, but I was able to boot, I heard the boot music, and the access signal was accompanied by sound. There is no problem testing the power board separately. After repeated trials and several times, the IGBTs that were replaced were burned again. My heart is really bottomless, and the user calls every day to remind me. The heart is a Taobao full set of boards (XYZ or something, after repairing and sent back to the old board only pay red and black), I thought that as long as the screen is not bad, even if the old version has to be repaired!
Today I am looking forward to unpacking, just a piece of Y board! Contact the seller and say "Sorry, I will reissue you immediately." I took the Y board machine and tried it. The machine has no problems and the sound map is good. Returning to the seller: I don't have time to wait for you to reissue. I have already taken SF from elsewhere, and the bad Y board is sent back to you at the exchange price. At this point, the stone in my heart finally fell to the ground. There is no abnormality in the test machine for several hours. Please contact the owner and send it to her tomorrow!
The process of repairing the plasma for the first time was quite embarrassing. It is estimated that the machine had broken a power board before, and the Y board was broken by me. It is really awkward! Going to the forum for help, there is no way to break the jar, but it is finally fixed. Tell the owner to charge green blue and brown, still no loss. To sum up, you should pay attention to the following points for newcomers:
One: Do not report the price of the plasma machine, the Y board is expensive, and it is a vulnerable part. Many faults cannot accurately determine which board the problem is in.
Two: For the power board can be tested separately, generally PS-ON ground, VS-ON connected to D5.3V, VS connected to 100W bulb to see the load capacity, measuring whether the output of other groups is normal.
Three: The board of some models must be screwed on to test the machine, otherwise the consequences are very serious. In particular, the Y board of this machine, the ground wire is not all connected, and there is a fuse resistor.
Four: Uncertain screen self-test method, do not try it. It is said that some cables may burn the board if they are powered off after being unplugged. After unplugging the cable tester, insert it back and wait for the voltage to drop and then plug it in, otherwise it will damage the board.