TCL LCD TV L37M61B boot blue light is sometimes no image repair - android - Phones Developers

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I recently worked on a TCL LCD TV model L37M61B that was experiencing an issue with the blue light being bright, and sometimes there was no image at all. The TV would need to be restarted multiple times before the screen would display properly. Additionally, the screen occasionally showed sparks or a strange pattern, which made it difficult to use.

My first step was to check the power supply. After testing it with an Agilent U1252B digital multimeter, I found that the power supply itself was functioning correctly. However, while measuring the voltages from the motherboard’s voltage regulator blocks, I noticed that the 3.3V regulator had some issues. The AC voltage was higher than normal, which suggested poor filtering.

To fix this, I added two additional electrolytic capacitors to improve the filtering of the 3.3V line. After making this modification, the blue light stabilized, and the image appeared consistently without any sparking or distortion. This simple repair saved the customer from having to replace the entire TV.

Here are some images from the repair process: