Because the P-N junction of the internal chip will emit a lot of heat after the LED runs for a long time, which causes the temperature of the LED PCB to rise and the internal resistance to increase. When the power is turned on, most of the electrons are concentrated in the PCB board with high internal resistance, which will cause the current of the circuit board to become higher and higher. It is recommended to check the internal resistance of the PCB board when welding the circuit board and install a Zener diode when soldering the LED lamp to protect the LED lamp from being burnt by a high current. When using LED lights, the current should not exceed 20MA. Must add a current-limiting resistor! There are other possible reasons: 1. The LED lamp beads or resistors and other components have been damaged; 2. The details may be soldered or unsoldered during the LED PCB assembly; 3. The circuit board may be short-circuited, and a multimeter can be used to detect the components.