Two led lights are on, and the others are not. SMD ceiling lamp is slightly bright after turning off the light. The capacitors in a group of unlit power supplies do not match and cannot be completely discharged. There are too many electric particles in it, and the power supply flashing on the surface is broken. This possibility is great, because it can be lit by turning on the flash.

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.