1. The LED dead light does not light up. It is enough to replace the LED, but please note that the positive and negative polarities cannot be reversed.
2. The lead-acid battery is damaged, which can not be charged and discharged, and it can only be used when plugged in.
3. The high-voltage step-down capacitor is damaged, or the over-voltage of the rectifier diode is damaged, resulting in failure to charge. At this time, ordinary pointer multimeter can be used to detect and solve the problem.
4.Pull switch is in poor contact or damaged and cannot be conducted.