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SMD Led Based Rechargable Chinese Led Lamp Repair

SMD Led Based Rechargable Chinese Led Lamp Repair



This is a chinese made SMD led based rechargeable lamp. The problem was that the battery was not charging. I opened up the circuit and found a transfromerless power supply used to charge the battery. The Circuit has a x-rated capacitor, 4 diodes to produce DC.

I powered on the device and checked for DC voltage and there was no voltage. I then suspected some issue with the rectification section build around 4 IN4007 diodes. I checked all the 4 by desoldering them from the PCB and found one to be open circuited which offered a very high resistance.

I replaced the diode with a new one. I powered on the circuit and was glad to find DC output from the bridge section. I then kept the power on for 30 mins which charged the battery and finally the lamp was brought back into life.

WARNING
Take utmost care while working with AC voltage !!

In case if you have any doubt/ suggestions/ query, please leave them on the comments section below.
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Tags: smd led

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6 Comments

  1. Date: January 26, 2017 at 14:20
    Author: Ramu G

    mine also got problem , nearly same with slight different circuit board , one capacitor of 100 uf 50 v & one of my resistor is burnt , i replaced capicotor but i cant find colour coding. Im confused what value resistor to replace. Any ideas u got dude..

  2. Date: July 17, 2017 at 17:29

    my problem is that after i replace the burnt resistors that are two in number and one capacitor in my emergency charger light, the latter get burnt again when put on charging. its the third time i have replaced all those burnt components with new ones but in vain

  3. Date: July 22, 2017 at 09:44
    Author: Abhi G

    i have the same light with same battery and circuit… unfortunately capacitor got damaged in such a way that i can't even determine its value…pls tell me the exact value mention on that components..

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