Konka LC-TM2620 LCD TV with black screen. First, I checked the backlight power supply and it was normal. Then I tested PBACK and found it to be 0V, which suggests a problem with the motherboard. Next, I inspected the motherboard's CPU for DC-DC conversion, specifically looking at U802. You can see the image below:
When checking the resistance from pin 3 of U802 to ground, it showed 0 ohms. This indicated a possible short circuit in VD802. After replacing VD802, the screen turned on for about 15 minutes before going off again. I then rechecked C814 and C850, but they were fine. However, after replacing C813, everything returned to normal. It seems that the issue was related to a faulty capacitor on the motherboard. This kind of repair requires careful testing and component replacement to ensure long-term stability.
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