LED Bulb Repaired
Found my workbench LED Bulb not light up.
Removed top cover for inspection.
On visual inspection I found two LEDs were damaged and top coating chipped out.
For further testing I just pulled out the led plate to inspect Driver PCB underneath. Driver circuit seems Ok no physical damage found.
So I tested rest of the LEDs using my DIY tweezer specially made for testing purpose using 3v Adapter.
On testing rest of all LED working OK. Total 18 LED used in this circuit & Bulb rated 5W so these 2835 led are of approx. 0.275w, I do not have replacement LEDs with me so decide to make jumper on each bad LED.
you can make jumper on maximum two LEDs, if more than two LEDs are bad, Bulb will work but for limited period. I have repaired one bulb with two bad LED by Jumper, approximate 3 years back still it was working fine.
After making jumper I powered it.
And found Bulb is back to the life.
This article was prepared for you by Yogesh Panchal who works as a Computer Hardware Engineer in Mumbai India.
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Note: You can check his previous repair articles on SONY CYBER Shot Battery Charger Repaired
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Parasuraman S
August 31, 2024 at 5:32 pm
That was a smart short cut done by you! But it is ok, for our own use. Cannot give to a customer, as the life is not guaranteed. My experience showed that other LEDs would fail one by one. Thanks for sharing a unique work!
Yogesh Panchal
September 5, 2024 at 3:39 pm
You are right sir, if quality of the circuit is good bulb will last longer,i still using few bulbs was repaired same way 2 to 3 years back.
Albert van Bemmelen
August 31, 2024 at 6:18 pm
If shorting defect leds is a success mostly depends on how many leds that are used. The more that are used the greater the chance of success no doubt. I once accidently put a 12V led light bulb in a 230V AC socket. It worked very well several minutes until I noticed my mistake thinking it was a 230VAC led bulb.
It still wasn't damaged at all but probably made with good parts only designed for lower voltages.
Yogesh Panchal
September 5, 2024 at 3:41 pm
Albert,
Current control IC will take care in some good quality circuits.
Mark J
September 1, 2024 at 12:09 am
Yogesh thank you for sharing.
Yogesh Panchal
September 5, 2024 at 3:42 pm
Thanks!Mark j
Tayo
September 1, 2024 at 12:13 am
Excellent fix here. So here's my question .... I learned from you guys that replacing a defective LED(s) was not a good solution as to would affect/short the lifespan of the other LEDs it/they were connected to. But when I read that you were looking for replacements I found it odd based on the fore mentioned reason. replacing them with a bridge makes more sense as all the remaining LEDs will share the extra voltage and since they are all the same age it would be okay. Why, when and where would we want to replace the LEDs rather than bridge them?
Thanks in advance
Yogesh Panchal
September 5, 2024 at 3:47 pm
Thanks! Tayo,
If driver circuit is having current control IC You can bridge the damage LEDs but if Driver circuit is not having Current control IC we have to replace the Exact power of LEDs for proper working.
Serghei
September 1, 2024 at 4:25 pm
LEDs are supplied by current regulators NOT voltage regulators, so shrinking de LEDs number will rezult in downing de voltage applied to LEDs, keeping de current constant.
A very good idea is to modify the value of CS (Current Sense) resistor, usually 0,5 to 1,5 ohms to bigger values, dimming the current through LEDs to safe values.
Yogesh Panchal
September 5, 2024 at 3:49 pm
Serghei,
Thanks! for your explanation.
Waleed Rishmawi
September 2, 2024 at 4:37 pm
in my experience, every time I do this modification the light burn again in less than a month so I stopped doing that. they are very cheap in my home town and it cost less than a dollar so it was not worth the time spent on it unless I am fixing my own light for the shop but for a customer I am not will to do such repair. thanks for sharing and have a blessed day
Yogesh Panchal
September 5, 2024 at 3:51 pm
Waleed,
if driver circuit is of good design with current control IC, bulb will last longer.
Henrique J. G. Ulbrich
September 2, 2024 at 11:21 pm
Godd job, Yogesh. From your text and also from responses from others, I can say the following:
1) Good products make the LEDs operate on constant current, as Tayo and Serghey say. That´s the correct and professional solution, although perhaps some low-cost lamps use constant voltage. Perhaps the lamps cited by Waleed were of constant voltage, which can explain why they burnt soon.
2) When you bridge LEDs in a series circuit, as used in this type of LED lamp, the constant current driver adapts itself, correcting immediately to the rated current. In other words: the remaing (still operating) LEDs continue to work with the same rated current as before.
3) This perhaps explain why Albert didn´t killed their 12 V lamp. The constant current circuit, in one way or another, limited the power and succeed in keeping the correct current for the LEDs. Good parts inside, as Albert say. It is curious that a 12 V lamp probably is for DC, and the 230 V applied is AC. It is necessary to observe the driver circuit to understand.
4) You can replace defective LEDs without affect the other still operating LEDs. Although the same LED type must be used.
Yogesh Panchal
September 5, 2024 at 3:53 pm
Henrique J. G. Ulbrich,
Thanks! fro your Explanation.
Darie Lau
September 3, 2024 at 9:18 am
It is a good try to repair it by using the shorting defect LEDs method for temporary use. You have enough time to buy or order a new one from web shops.
Yogesh Panchal
September 5, 2024 at 3:54 pm
Darie Lau,
Thank You!