First, watch the full video then You will understand Everything. It is an easy step by step guide for repairing this types of Chinese products..
Step 1: Open the Back Panel.
Your first work should be open the back panel of the LED light. as you can see there are 6 screws holding the back panel.
Step 2: See the Internal Components...
there are many internal components but I have divided the section into 3 parts.
1. light Section
2. Charging Section
Step 3: Checking Circuit Section
when we are checking the circuit section then in the most cases the ac capacitor aka PF damaged many times sometimes it blows off. If you find that it is damaged hen remove the PF and replace it with a new one ad it will be just fine.
Step 4: Check Bridge Rectifiers With Multimeter
Step 5: Battery Setion
the main reason for damaging any emergency light is for the battery. if the battery overcharged or over discharged then it may happen. I that case you have to remove the battery and replace the battery with a new battery. and it will just work fine.
one thing I forgot to say you guys is that the switch you have connected to the board may also be damaged so in this case you can use any type of oil or just replace the old switch with a new one. It will work like a charm.
Step 6: Charge the Battery for Several Hours
after the charging, the Emergency light is working like fine.