Reconstructed with waste circuit board to transform Konka color TV F2109E no sound failure - News - Global IC Trade Starts Here.

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A Konka F2109E color TV was experiencing an issue where there was no sound, although the image quality remained good. The tracking sound block TDA7056 was in good condition, and the power supply was functioning normally. However, when using an oscilloscope to check the input waveform, it wasn't normal, and the digital chip's audio conversion also failed. This led me to conclude that the problem was with the chip itself. Since I didn't have a replacement for this specific chip, I decided to modify the audio circuit using a salvaged board. First, I searched for a circuit board with a working audio section and carefully cut it out as shown in Figure 3–4. It’s important to verify that the voltage levels between the salvaged board and the original board are similar before proceeding. After confirming compatibility, as shown in Figure 5, I added a 2W 10–20R current-limiting resistor at the power input and included a 10K–40K noise-reduction resistor for the audio input (marked in red on the diagram). In Figure 6, I took the voltage from the original 16V power source while disconnecting the original TDA7056 power supply. Once everything was set up, I tested the modified system. The audio signal was directly input from a set-top box, and the volume was controlled using the remote control. The main audio block used in the modification was the TDA2003, which can be adapted or replaced with other audio chips depending on availability. This method is not only useful for fixing this specific TV but can also be applied to solve various audio-related issues in other devices. I hope this sharing helps others in their troubleshooting and learning process. Please note that this is for reference only and should be done with caution.