Reconstructed with waste circuit board to transform Konka color TV F2109E no sound failure - News - Global IC Trade Starts Here.
A Konka F2109E color TV experienced 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 properly. However, when using an oscilloscope to check the input waveform, it appeared abnormal, and the digital chip's audio conversion wasn't working correctly. This led to the conclusion that the problem was with the chip itself.
Since a replacement chip wasn't available, I decided to modify the audio circuit using a salvaged board. First, I found a circuit board with a working audio section and carefully cut out the relevant part as shown in Figure 3–4. It was crucial to verify that the voltage levels between the scrap board and the target board were similar before proceeding.
After confirming compatibility, as illustrated in Figure 5, I added a 2W 10–20R current-limiting resistor at the power input and included a 10K–40K noise-reduction resistor on the audio input (marked in red in the picture). In Figure 6, I took the 16V power from the original circuit while disconnecting the TDA7056 power supply from the original board.
Once all connections were made, I tested the setup. The audio signal was directly input from a set-top box, and the volume was controlled using the remote control. The replaced audio section used the TDA2003 chip, and this circuit could be adapted or modified using other audio blocks as needed.
This method can also be applied to fix various audio-related issues in different TVs. In summary, this is just a shared experience for reference and learning purposes. I hope it helps others who are facing similar problems.
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