Xiahua color TV TS2580 "three no" fault repair process - android - Phones Developers

The TV had no response when powered on. After removing the back cover, I noticed that the fuse was blown. It looked like this.

The resistance of the 300V filter capacitor C507 was approximately 2KΩ. If there was a short or leakage, disconnecting the jumper of the degaussing resistor revealed that it had also been deformed. Here's what it looked like.

Then, I disconnected the jumper connected to the drain 1 of the N501 power block. The resistance at both ends of C507 remained around 2KΩ. Looking at the schematic, only the one-pin wafer capacitor C508, connected between R509 and N501 start resistors, was linked to the large electrolytic C507. Measuring the starting resistance of R509’s bright pin showed normal readings. Eventually, only the small wafer capacitor remained. Checking the motherboard’s circuit diagram, I found that C508 on the switch transformer side had cracked, which explains why it wasn’t visible before. I decided to remove C508 and measured its resistance, which was about 2KΩ. At this point, measuring the resistance of C507 again showed noticeable swings in forward and reverse directions.

Meanwhile, there was no obvious short circuit on the secondary output of the switching transformer. I replaced C508 with a 1000/1KV capacitor, and for safety, I used one rated at 2KV. Temporarily, I didn’t reconnect the fuse but instead connected an incandescent bulb. When I powered it on, the bulb flickered, indicating that the system was working properly. At this stage, I replaced the fuse, the degaussing resistor, and reconnected all the cables. The TV started up normally, and the picture and sound returned to their usual state.