[Sharing] is the fault of Jiaojiao--- Skyworth 32L08HR (8K22) from time to time screen dead machine maintenance - Home Appliances

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Brand AVX TPSE226M035R0125 Low impedance tantalum capacitor AVX 22

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Skyworth 32L08HR8K22 movement, user introduction may look at half an hour or maybe more than two hours full screen vertical bar without image, accompanied by rustling, when the screen is a dark flash.
Take a look at the next drawing:
[attach]475950[/attach]

According to the user's thermal machine failure, it is estimated that it is related to the temperature, and the maintenance preparation is ready: 1. Unpack the rear cover, remove the shielded iron box of the main board, and observe the basic structure of the circuit.

Second, the Internet search to see if there are shortcuts to go, you do not say that you really found the typical symptoms, online said that the DDR memory power supply caused by the communication loop, it makes sense, and expected.
Third, the power is connected to the DVD player to put a karaoke, while listening to the song while repairing is not bad. The main board was blown up with a hair dryer, and it seemed that it was waiting slowly. Because the open back cover is well ventilated, it is not conducive to the recurrence of the fault, and put something on the motherboard to make it warmer. Then sit down and surf the Internet while quietly waiting for the enemy to show up.
More than half an hour of failure finally appeared, accompanied by intermittent rustling, immediately measured U11 output normal 2.6V has downward jitter, has not measured the input voltage and the eye voltage is normal, but still rustling, the screen is still screen.
[attach]475966[/attach]
Hand touch U11 is hot, it may be that it is bad (LT1085--ADJ) first replaced. But the hope is full, and the reality is very skinny. The fault reappears after 10 minutes of power on. After persistent perseverance, I finally found out the general route of the enemy's sneak attack: the auxiliary power supply 5V, the standby control (ON) 3.8V is always stable, and the main power supply 12V, 24V occasionally reduces the jitter. Hey, the enemy's home is on the power board.
Remove the power board and look at the reverse side. There is no drawing at hand, according to the general analysis of the object, there are three optocouplers on the board, one is the sub-voltage 5V voltage regulator, one is the 12/24V main power supply voltage regulator, the middle optocoupler is the main power on/standby control, is the control Powering the PFC and the main power chip. This time it seems that there are ghosts and gods to help, a few moments of boot failure. The 23V supply of the PFC and the main power chip fluctuated or even dropped to 0V. At this time, the standby optocoupler 1 and 2 feet are measured without voltage, but the optocoupler 1 pin power supply current limiting resistor (the manufacturer is lazy and not printed with the upper digit). The other end of the 5V is always normal.
[attach]475973[/attach]
Blowing down with X1K file can not be measured, measured with X10K file and the resistance is very small, and then measured with X1K file is 5--10K unstable. Replace with a 102 resistor,
[attach]475974[/attach]
The result will not be said. A lot of pictures are too lazy to send effect photos again.



The resistance on the board is much older. Why is it worse? ---- It is the fault of the glue!



The previous article "is a catastrophe":
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