9 Watt LED Light Bulb Repaired
This LED light bulb was stopped glowing, but why? Then I started to know.The first challenge was how to open this? no screw! but the body of light bulb was consisting of two materials and two kind of polymer then I started to scratch the edge between the bulb and stem of light bulb by a tip of a sharp knife, yes there was glued and with not very strong ones I separated the bulb and the stem.
Inside I found 18 LEDs that were installed on a circled PCB all of them were in series with each other’s the power supply of light bulb was inside of the stem but the output of the power supply white and grey wires was soldered on top of the pcb.
Then I desoldered the wires from the PCB power supply and with the help of a multimeter, I checked the output and yes there was 211-volts DC output which mean the power supply was good.
Since all the LED were installed in series with each other’s, the chances would be high if one of the LEDs were to open circuit, the rest of the LEDs will not light up. A very quick tool for checking the LEDs is a 9-volt battery.
With the attached wires, I then started to check one by one LEDs with the help of a 9-volt battery. All of the LEDs were found to be good except one. Due to a bad LED, the rest of the LEDs were not able to light up. I replaced with a good LED and the bulb was lighted up again.
For your information it is also possible to check the LEDs with the help of multimeter and Buzzer Tool. The cost of this repair was 1/10 of a one American cent.
NOTE 1:
In CANDONG CHINA, ZONOOPO INTELLIGENT TECHNOLOGIES COMPANY recently invented a new power supply DC-DC IC for LEDs and this IC act as a power supply. The code of this IC is ZON OPO 8290
This is the new generation of LED light bulb with no power supply and is cheaper and lighter. The bridge rectifier rectifies the 220 v AC voltages and 8290 regulate and stabilize the voltage for LEDs the output is 211-volt DC no need decreasing transforms and other actors of SMPS power supply like caps and regulator IC so and so… LEDs of light bulb consume this voltage very softly that is all.! Actually this is a revolution in these kind of led lights.
NOTE 2: When testing the LEDs we have to observe the polarity of battery as well as the polarities of LEDs
NOTE 3: In my country part supplier and repair of LEDs lights is a business that both concentrate in one shop. Buying a new led light more or less is expensive that is why the repair of them is reasonable.
Note 4: Also it is possible even without any new LED repair the light. first we have to remove the opened LED from the board then by soldering the two pols on the PCB board make a connection between two pols and keep the continuity of circuit this cause the light bulb to turns on again this is with no cost method of repair .
This article was prepared for you by Mr Beh from Iran
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Parasuraman S
December 12, 2019 at 9:24 pm
That's new to me. I have always seen an SMPS inside good quality LED bulbs. The Chinese use capacitor dropping with rectifier diodes. Learnt something new, I think. Many thanks for sharing! Good job there!
beh
December 13, 2019 at 11:35 pm
You are welcome. but I want to draw your attention for part 2 of this article that makes you wonder more
Albert van Bemmelen
December 12, 2019 at 11:14 pm
Good job Beh. The ZON OPO 8290 probably indeed is new power control IC for these led bulbs. But I know that the LNK302/304-306 LinkSwitch-TN ICs are already used a couple of years now in a similar way in washing machines and dryers. And can also be used to drive Leds directly connected to the 230VAC power line after the input is rectified to DC. And other ic types like the TNY 274-280 exist that do the same.
beh
December 13, 2019 at 11:42 pm
ALBERT
yes, this is quite possible but recently my LED got sick and I decided to know why? and this story started for me and got these facts and i shared with all
Robert Calk Jr.
December 14, 2019 at 7:37 am
Hi Albert. I left you a comment on your article," Systematic Repair On A Device With The Help Of DCA 75 Pro And Hand Drawn Schematic". I guess that you didn't see it.
Paris Azis
December 12, 2019 at 11:36 pm
Hello Beh,
Sometime in the past I tried as an experiment your No 4 alternative, but unfortunately there was a tendency of the remaining leds to burn one after the other. Perhaps this lamp had run for "too many kilometres"! This method is relatively successful when only one led is replaced on a new bulb. After the first one removed from the circuit and replaced by a solder bridge, the current rises to intolerable level for the rest of the leds. If a second one is removed, then the "domino effect" begins and they get burned one after the other like matches.
One way or another, I think that these bulbs (all technologies applied so far) should be banned instead of the poor old incandescent one. And this for many reasons. I just name a few. A) what you save in electricity, you spend it double or triple for replacing them because they don't last as long as the incandescent ones. B) they worsen the power factor of the grid. C) as already said they do not last for long and therefore are no cheap at all! D) when thrown in the garbage bin they kill the environment because a bunch of electronic material, no matter if it's working, it's thrown away. More plastic, more chemical waste and more useful material along with it burdens the environment. E) recently ophthalmologists accuse them for harming our eyesight. With the incandescent lamp we had only the Tungsten filament, the glass containing it and the metallic base. Much more easy to recycle them even in the case that both types are ending at a recycle bin. Perhaps this is another way for factories to make some more money. As usual in other words...
Robert Calk Jr.
December 13, 2019 at 8:02 pm
That is true, Paris. Here in the USA we are going back to incandescent bulbs thanks to President Trump.
beh
December 13, 2019 at 11:47 pm
ROBERT
This kind of light that you mentioned is very energy consuming who pays the bill?
Robert Calk Jr.
December 14, 2019 at 11:55 am
Hi Beh. When you tally up the waste of LED lamps and the hazardous materials in fluorescent and other bulbs, incandescent bulbs are way cheaper in the long run and better for the environment.
Maurizio C.
December 14, 2019 at 11:56 pm
serious?
beh
December 21, 2019 at 12:36 pm
YES!
beh
December 22, 2019 at 10:13 am
Maurizio
yes. because millions of LED lamps are waiting in the world to receive such services and easily we can make money and also keep the natural resources of our mother earth that is why this is serious!
beh
December 13, 2019 at 11:31 pm
Hi Paris
yes, this is true .and that is why I named this method at no cost. but in part -2 of this article, I will show you all a very easy and cheap and safe way to repair such LED LIGHT without any technical problems
Paris Azis
December 14, 2019 at 5:32 pm
Hello again Beh,
I have long ago experimented with these bulbs. I am convinced that the leds used in them are working at the verge of their electrical limits. At their maximum current in other words. Apart from that,there is not even an elementary means of protection against overvoltages, especially when they work in an industrial environment, where the grid is full of electrical garbage.
Now, when diodes are connected in series, they need to be matched. But this "has a high cost". Therefore they used accidentally selected. This renders the circuit very vulnerable to failures. There are of course countermeasures, such as the use of balancing resistors connected in parallel with each diode. Even better, complex circuits could be used including transient absorbing capacitors. These methods would render these bulbs really bullet proof. But marketing stays always in the middle. And finally they are left in their poor fate.
The cheapest trick I found, is to remove all the electronics from their base and build a transformerless power supply (using a single capacitor). There is even no need to use a rectifier. The point is that the capacitor must be properly calculated. This means that perhaps two caps will be needed in parallel. The idea is to divide the total group of diodes in two sub groups connected in antiparallel (forming something like a diac). Then connect the capacitor to one end, in series. Finally connect the free end of the cap and the other of the diodes directly to the mains. Or you can let the diodes as they are and connect a diode at the ends of the group with reverse polarity and then add the cap. If the properly calculated capacitor (X2 series, etc) provides the circuit with the half of the original current, your bulb will be practically immortal. But remember. If you do this for your customers, you will soon be bankrupt!! My greetings to you dear!
Parasuraman S
December 14, 2019 at 8:03 am
Yes! Very true to every word written!
Rathindra Nath Biswas
June 8, 2020 at 3:28 pm
These chinese leds are lousy gadgets & fails within 2days , even when retrofitted with resistance fuse & MOV . I have thrown them to the garbage . Always use items made in your country , that may be costly , but economical in the long run .
George Nutzul
December 13, 2019 at 11:52 am
As pointed out by Paris, it is not advisable to bridge out a defective LED with a shorting jumper... the higher current will prematurely destroy the remaining LEDs quickly. Here in the USA, LED bulbs can be purchased at Dollar Tree stores for $1.00US, so its not worthwhile to even open the bulb for repair. They must be expensive in Iran to even attempt a repair. But thanks for the article, and the info on the new driver technology coming.
beh
December 13, 2019 at 11:38 pm
yes the best way is to replace all the LEDs and i will explain in next article soon
Robert Calk Jr.
December 13, 2019 at 8:07 pm
Hi Beh. Good job saving the LED lamp from the garbage! I could not find a datasheet on that number you gave for the 8290 IC.
beh
December 13, 2019 at 11:51 pm
ROBERT
yes you can not find any data and i did not but this ic s really work .in next article I will show you best way for repair of these LEDs
Waleed Rishmawi
December 14, 2019 at 4:10 pm
good job on the repair. yes, adding a new LED light in the place of the burnt ones is the best way to go. In case a replacement can not be found I will short out the terminals and get it to work again but for short time. have a blessed day and again a job well done
beh
December 14, 2019 at 5:23 pm
You are most welcome WALEED.
Henrique J. G. Ulbrich
December 17, 2019 at 12:52 am
Good information, Beh. Although I am replying only 3 days before, I have a doubt: If we have 211 V for supplying 18 LEDs in series, this means about 11,7 V per LED, a value outside any LED specification.
beh
December 20, 2019 at 7:43 pm
you are welcome . yes this is true i measured this voltages by a very precises digital multi meter. also i was wonder too. but i may ask you to correct me by measuring these voltages by your own multi meter to many things are happening in Guangzhou of china that i did not know.
and thanks for your very technical comments that sending to my articles
humberto
December 18, 2019 at 1:09 am
Hi beh, an interesting article. Thanks for sharing it
beh
December 20, 2019 at 7:35 pm
HI HUMBERTO
you are welcome.long time no news from you !part-2 of this article is more interesting and contain ultimate answer to repair these kind of LED
lamps .
behzad