Burning machine method to repair Konka LED32F1160CF three no cases - Home Appliances

MOS power IC full range

Filter 18.432M

A few days ago, I got a broken Konka LED32CF1160CF TV with no picture and no sound. After opening it up, I found the mainboard is a 3-in-1 type. The first step was to check the power supply using a VC9808 multimeter. The fuse was fine, and the 300V capacitor had about 30V left. The resistance between the S pole of the power switch transistor and ground was normal. But when testing the secondary side of the switching power supply, I noticed that the 12V rectifier VDW963 MBR20100 had almost zero resistance in both directions, which was strange.
This small 20100 diode can easily be damaged by high current surges. So I decided to replace it. After replacing VDW963, I tested it again with an analog meter, and it worked fine. That meant the short was likely coming from the 12V filter or its load. The 12V line goes to several places: the power supply chip V8019435, the backlight booster N701OZ9902C, the DC-DC converter N803AP3502E, and the power amplifier block N202PAM8006A.
Without proper tools, I used what I had. I connected a 3.3V power source (capable of 6A) to the negative side of VDW963. After touching it twice, I saw smoke coming from the N803 area. I quickly checked the components and found that C898 was bad. I replaced it with a 10UF capacitor, and also changed the inductor L805 near the 12V input to prevent any high-frequency interference.

After powering on, the TV worked perfectly—picture and sound were back. I marked the repair date on the TV, closed the back cover, and called it a day. It was a tough one, but it's always satisfying when everything comes back to life.