It's been a few days since South China officially entered late autumn, and the weather has turned cool. It felt great to say goodbye to the summer heat, and I was in a really good mood. In the afternoon, I had planned to go hiking with some friends on the outskirts of the city, but an unexpected call ruined my plan. The LCD screen of the leader of the ruling party had broken down, and he asked me to help fix it.
The model is Shinco TDV-4621, a color TV. The issue was that there was a green band about 3 cm wide on the left side of the screen, and the image also showed green interference at dark areas, but there was no sound. During the repair process, I first checked whether the problem came from the power supply or the digital board. I switched the TV to AV mode, and the blue screen was full of green spots. Based on experience, I suspected the power circuit was the culprit.
I opened the back cover and visually inspected the components. I noticed three capacitors were swollen—two were +12V filters, and one was a +5.7V filter. I quickly replaced them and powered up the TV. The image looked great, and the first fault was resolved quickly.
Next, I addressed the silent issue. I first checked if it was a channel or power amplifier problem. I used the DVD that came with the TV, set the volume to maximum, but there was still no sound. It seemed like the problem was in the power amplifier circuit. The power amplifier was a small 48-pin SMD IC, model TPA3008D2. The layout was compact, and it was double-sided soldered, making it difficult to work on. Plus, I didn’t have the datasheet handy, which made the repair even more challenging.
After a lot of effort, I finally found the IC’s datasheet. I checked all the working voltages, and they were normal. But the speaker remained silent, so I suspected the IC was damaged. Where could I get a replacement? I took a closer look and made a decision based on the information I had.
According to the datasheet, pin 1 was the mute function, controlled by a transistor. The voltage on the base wasn't changing when using the remote control. Then I realized the CPU might be connected through a small wire. After thinking for a while, I removed the mute transistor and powered the TV on. Just like the song "I Am a Little Stone," everything worked perfectly! My friend’s son said, “Uncle, you’re too powerful!â€
Later, I learned they had previously taken the TV to a well-known electrical repair shop in the city. They had the unit dismantled and were told they needed to replace the digital board, which would cost around 850 yuan. However, since the machine used a DVD-connected motherboard and there were no new service points in the city, they decided to give up.
Fixing it myself was a win-win situation—it cost less than 850 yuan, and I saved the day! Haha!
My advice: Sometimes, not following strict rules can lead to better solutions. If you need to replace an IC, it may not always solve the problem, especially if you can't find the right part. Think creatively—sometimes a simple fix, like desoldering the mute transistor, can do the trick. Why not try it?
Here’s the TPA3008D2 datasheet I downloaded. This IC is used in many LCD TVs, so it might come in handy for you in the future. Thanks!
Rca Connector,Screw Terminal Block Adapter,Rca Phono Male Connector,Rca Phono Female Connector
Changzhou Kingsun New Energy Technology Co., Ltd. , https://www.aioconn.com
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