I've one emergency light from AliExpress, with rechargeable LED lights that automatically turns on when there’s a power outage. You plug it into the wall, it charges an internal battery, and when the mains goes off, it lights up the room.
After some time of use, it suddenly stopped working. Opening it up, the reason was pretty obvious: one of the electrolytic capacitors had exploded.
The failure didn’t stop there, the blown cap also burned a small transistor near it, and even some of the LEDs on the main board were dead.
Luckily, the circuit is simple. I replaced both the damaged capacitor and the transistor. For the LEDs, I salvaged some working ones from an old broken LED bulb I had lying around.
After soldering everything back and cleaning up the board, the light powered up again — working perfectly both from mains and battery.
Notes
- read risk disclaimer
- excuse my bad english