It is ruled out that the lamp bead power supply is not well matched with the used wire string, resulting in excessive local current. If the voltage step of the lamp bead is too wide or the chip is too small, it will increase the current resistance and slow down the capacitor discharge. There may be some problems with the power control IC. Based on the above analysis, there may be two points at most. One is a capacitor or transformer and an integrated circuit. The specific situation requires physical analysis. For reference only.