Replacement of Defective Capacitor in E27 LED Bulb




About: man who don't know too much, but know enough

If you own an E27 LED bulb that flickers at start up or doesn't reach full brightness anymore, don't throw it away! Just change the electrolytic capacitors in the power supply.

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Step 1: Inspection of Bulb

The power supply in LED bulbs is designed to occupy minimum space in the lamp and at the same time ensure the most power.

The weakest link in the chain is usually an electrolytic capacitor with a working voltage of 400V. When it begins to age, the bulb will not achieve full brightness. Replacing the defective capacitor will often solve this problem.

Almost all E27 bulbs open simply by unscrewing the light bulb's pear-shaped housing. Do it gently to avoid damaging the connecting wires. Carefully pull the circuit board from the bulb. The damaged capacitor is usually inflated and visibly damaged. If possible, read the information on its capacity and voltage. A common value for 3-5W E27 LED bulbs is 4.7μF at 400V.

Step 2: Replacement Electrolite Capacitor

Replacement capacitors are available in any store selling electronic components. When mounting the capacitor, pay attention to its polarity. Reversing the plus and minus leads will result in damage to the capacitor and possibly to the circuit as well!

The greatest enemy of LED lighting is the heat that it it generates; it will rapidly shorten the life of the lamps. If the abovementioned capacitor fails, replacing it will usually repair the lamp. However, if an SMD component fails, repairs are usually not possible. In that case, you can buy a new driver board or continue to use the bulb on 11-13V DC depending on the model.

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    6 Discussions


    5 years ago on Introduction

    Simplest way is . There you can buy only cases, but be careful because shops deals with a varied prices .


    5 years ago on Introduction


    may I ask you which bulb is that? I had one (doesn't know company - made in china) and I could disassemble it. Than I use a little force and found out, that everything inside is covered by "plastic" or something (I don't know how to call it). So I would like to know where can I get bulb like you have?

    Maybe you know, if there can be bought only "case" without circuit and leds? I want to experiment something and need empty bulb.

    Thanks for help!


    6 years ago on Introduction

    What is that TO262 power transistor looking package to the left of the electrolytic capacitor? I am always on the lookout for new parts to scavenge.


    7 years ago on Introduction

    Fantastic information. Since E27 LED bulbs are proliferating, we will see many more of these failing. Thanks for sharing this!


    1 reply

    7 years ago on Introduction

    Thanks for the comment,

    LED lighting technology is indeed noble, but too high prices.
    It seems that the LED is really long.
    I have 3x1W LEDs working virtually non-stop for about 3 years and before that was used, and they are 6 years old CREE XL 7090 model 350mA 45lm / W.

    and diodes are buried three power supply so far.