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TCL color TV HID29276PB boot smoke problem repair - android - Phones Developers
During the viewing process, a TCL color TV model HID29276PB suddenly emitted an unusual noise and smoke from inside. After removing the main circuit board, I discovered that resistor R419 was burned. Checking the data, I found that R419 is a 1K (0.125W) resistor, which serves as the ABL output resistor in the high voltage package.
Overhaul process:
1. I replaced R419 with a 1K (0.5W) resistor. After installation, when the TV's high voltage started, it smoked again. Upon inspection, not only was R419 burned, but also R425 and R426 were damaged.
2. After replacing those three resistors, I rechecked the line tube drive circuit and power supply voltage. No abnormalities were found, but the three resistors burned again.
3. When I couldn't find the issue, I turned to online forums for help. I posted my problem and received some useful suggestions. With the assistance of others, I re-examined the row tube drive circuit and the ABL video panel control circuit. I found that resistor RN425 on the video panel was also burned.
4. I ordered a new high voltage package (model: BSC29-0185V) and a video board (model: 40-29206P-DIA4X), which cost a total of 64 yuan.
5. I received the parts this morning. After installing them, I powered up the TV. It had sound, but the screen was black. The resistors weren’t burning anymore, so I was confused—was there still a problem? I was about to shut it down and take the board out when I noticed three adjustable potentiometers on the high voltage package. I used a small screwdriver to adjust the SCR potentiometer and found that the TV displayed an image. After fine-tuning the SCR and FUS settings, the picture became stable and worked well.
6. The entire unit was reassembled, and after another power test, everything functioned normally.
Maintenance summary:
The original fault in this TV was caused by a faulty high voltage package, which led to abnormal ABL voltage output and subsequently burned R419. Later, when replacing R419 without addressing the root cause, it caused R425, R426, and RN425 to burn as well. If you encounter a similar situation, don’t replace R419 without first checking the high voltage package. Doing so could expand the scope of the fault. This experience taught me the importance of thorough diagnostics before making component replacements.