The first step in repairing a dead pixel is to determine the exact location of the bad pixel. To do this, we can use a microscope to observe the pixels on the display. Once the location of the dead pixel is determined, we can go further and determine the type of dead pixel. Common types of dead pixels include bright spots, dark spots, and color spots. For different types of dead pixels, we need to take different repair methods.

For bright and dark spots, we can try to re-solder or replace the LED tube. First, we need to reattach the solder joints with a soldering iron and solder to ensure good current conduction. If the welding is invalid, we can consider replacing the LED tube. Before replacing the lamp tube, we need to make sure that we have purchased the specifications and models that match the original lamp tube.