TCL LCD TV L32W3212 open screen change lamp beads - Home Appliances

I encountered a TCL-L32W3212 LCD TV that wouldn't turn on, showing a black screen. When I checked the constant current drive board, the 24V power supply seemed normal at first, but during startup, the output voltage spiked above 40V and then dropped back to 24V. To bypass the protection circuit, I connected a 1K resistor across C808, which allowed the screen to light up, but it remained black. I replaced the output filter capacitor with a 250V 22µF one, but the chip capacitor failure didn’t resolve the issue. These solutions were found through forum research.

The forum also mentioned that the LED lamp beads in this model are prone to failure, so I decided to open the screen and replace them. I started by removing the rear cover screws, placing the TV face-up on a flat surface, and carefully taking off the front case. I made sure not to lay the screen down to avoid damage. Then I removed the LCD panel and placed it safely. After that, I took off the backlight board to expose the LED light bar, which had seven segments.

Upon inspection, I noticed that six of the LED beads were not lighting up but weren’t fully shorted. The bottom segment had several beads that were broken down, so I decided to replace them. This was my first time replacing LED beads, and it took some trial and error. I used two soldering irons to remove the beads, which was quite challenging. I removed the plastic cover on the LED bead, heated the area, and then carefully lifted the bead using a pair of tweezers. It was difficult to get the bead off without damaging it.

I tried using an air gun to help with the removal, which made things easier. I held the light bar in one hand and used the air gun in the other. The beads were tough to place back, so I eventually used an old-style soldering iron, heated the area, and placed it on the table. I held the light bar with one hand and the bead with a pair of tweezers, gently lifting it off. I replaced all the faulty beads. Since I couldn’t find exact replacements, I looked for a similar light bar from a previously removed display. The length was slightly different, but it worked as a substitute.

After replacing all the LED beads, I reassembled the unit and tested it. The LED power supply voltage reached around 65V, and the image returned to normal. During the process, I noticed a white strip attached to the light bar. Originally, I planned to remove it when replacing the beads, but it became visible once the light bar was exposed. I simply uncovered a few parts, and some components were burned or deformed. I don’t think it affected performance much, so I left it as is.

Here are some photos for reference: