I recently encountered an issue with my LED TV-4006D, where the screen turned on but remained dark. After opening the display, I noticed that five of the backlight LEDs weren't lighting up. I also observed that two of the LED beads lacked a condenser lens and had their positive and negative poles soldered together. It looked like the TV had been previously repaired, but the technician didn’t replace the lenses properly and just reused the old ones.
I decided to fix it myself. I placed the five working LEDs back in place, used two-in-one glue to attach them, and tried to align the lenses correctly. However, after reassembling the screen, I noticed that two of the LEDs cast a faint shadow. The issue wasn’t visible when watching content, but it became obvious on a blue screen. I was worried—was it because the replacement lenses were slightly taller than the original ones, or did I misalign them?
I asked a colleague for his opinion, and he suggested that the problem might be due to the lenses not fitting properly. After adjusting them, the shadows disappeared. It’s important to be careful when working on screens, as repeated disassembly can cause more damage.
To better document the process, I’ve included some photos of the repair steps. Here are some images showing the LED beads before and after the fix, as well as the constant current drive circuit diagram for reference. I hope this helps others who might face similar issues with their TVs.
Limit Switch,Micro Limit Switch,High Limit Switch,Telemecanique Limit Switch
Shanghai Janetec Electric Co., Ltd. , https://www.janetecelectric.com