I recently encountered an issue with my LED TV-4006D, where the screen would boot up with a black display. After splitting the screen open, I noticed that five of the LEDs weren't lighting up. Additionally, I observed that two of the LED beads didn’t have a condenser lens attached. Upon closer inspection, I saw that the positive and negative poles of those two beads had been soldered together, which made me think this TV had already been repaired before.
What frustrated me was that instead of replacing the lenses, they just left it like that. I placed five working LEDs on the board, but only had the lenses in my hand. I used two-in-one glue to stick them back in place, worried that the lampshade might be misaligned. After reassembling the screen, I noticed that two of the LED beads were casting a slight shadow. It wasn’t obvious when there was a video signal, but it became visible during a blue screen test.
I was concerned about whether the problem was due to the replacement lenses being slightly taller than the original ones or if my alignment was off. I asked a colleague for his opinion, and he suggested it wasn’t the lampshade causing the issue. He recommended that I double-check everything carefully, as disassembling the screen multiple times could lead to more damage.
After testing again, I found that the issue was indeed with the lenses. The new ones were a bit higher than the original ones, and once replaced, the shadows disappeared. To make sure everything was clear, I decided to take some additional photos to document the process better.
Here are some images showing the repair steps and the final result:
I also included a few more pictures for clarity and to give a better sense of the work done. Another image shows the LED constant current drive circuit diagram, which helped me understand how the system worked after the repair.
Overall, the repair was successful, and the TV is now functioning properly. However, it was a learning experience, and I’ve learned the importance of using the right components and being careful with the alignment during such repairs.
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Shanghai Janetec Electric Co., Ltd. , https://www.janetecelectric.com