Here is a teardown of cheap mains powered LED night light from LIDL. After few years of use this light became very dim and so useless. I opened it to see what is in it and what was broken.
Let’s open it.
Circuit board details
Here is the circuit diagram. This is quite typical transformerless LED power supply that uses capacitor+resistor to limit LED current. There is also a rectifier and bleeder resistor for capacitor.
I measured resistors and capacitor. They were all good. The LED looked OK with multimeter diode test, but when tested with 20 mA current it gave very little light out.