Optonica 20 Watt LED Bar 4000K Repair
Recently another good friend brought his now defect Optonica led light bar. It was almost brandnew and already defect after only about 10 months of use. And because his warranty period was still good he already got a new replacement led bar why he gave me his now defect led bar.
Both caps on each end of this led bar have a connector to input 230VAC to all 100 leds. Which also makes it possible to easily connect another led bar to this one. There is also a small tumble powerswitch on the side of the bar.
Both wires were first unsoldered so the led stripe board could be shifted and pulled out of the round holder bar. And after prying out the mini tumble switch I also was able to extract a small power regulator board that was hidden under the led board inside the housing. More on that later.
After the ledstripe was extracted the first leds that were suspected to be bad showed black spots on top of them. And they indeed were defect including 7 other leds without any black spot marks.
And they all showed a very low voltage when I tested them with my handy led tester. And obviously none of those leds did work anymore.
Below LED TV Backlight tester is great in finding the bad leds and can also be used to safely test small smps power adapters on the 230VAC as I already wrote about in an older article on this blog.
Below photo shows the max test voltage when connected to the 230VAC input of the led bar after it is completely fixed. And the photo after that shows the working led bar connected to the TV backlight tester.
Because of the regulator power board that is connected inbetween the led stripe and the 230VAC input, the with my TV backlight tester measured operating voltage and here shown leds current deviates from the real values when the led bar is directly fed from the power line. Also giving light more brightly.
In total 9 leds were replaced. Below are the replacement SMD2835 leds shown that are used to replace the bad leds. 100 of them are about 1.67 euro/dollar free shipping. I only had warm white 3200 Kelvin leds in stock, but did order NATURAL WHITE 4000 kelvin 2835 leds that originally were used in this led bar according to the label.
Below photos show the stripe with 100 leds, and the 230VAC through both ends wiring.
Next photos show the cheap hot plate with a 230VAC PTC element that I used to easily remove the bad leds from the stripe. Both top and bottom plate are shown here.
This in the past cheap Aliexpress bought hot plate gets hot in seconds and takes a long time to cool off!
And here follows the more interesting part of this repair after removing and examining the earlier mentioned power voltage regulator board that is also hidden in the bar housing. That board carries a DP2866A Non-isolated Buck offline led-driver chip. Although searching for that chip resulted in finding the probably identical BP2866A led driver ic instead. That datasheet can be found here:
The yellow transformer looking part was measured being a 3.76mH coil with my Mastech tweezer tester.
Following photos show all parts more clearly.
Above left photo showed the DP2866A and photo right the diode. Next photo shows the board solder side.
Previous 2 with my portable digital LCD G600 microscope taken snapshots showed both ecaps with 2.2uF 250V and 8.2uF 400V value.
And above snapshots showed the red capacitor being a 400V 100nF value. And the blue 07D471K part must be an overvoltage protecting VDR.
Underneath the above visible red C1 400V 100nF capacitor there most likely is a bridge rectifier placed with board marking DB1. As shown more closely on next board side view photo.
Before I was able to pull out the hidden board with the DP2866A Non-isolated Buck offline led-driver chip I first had to pry out the small tumble switch to get it out of the way.
Following photos show the completely fixed led bar that will be of good use in my electronics shack.
After this successful repair the question remains why these leds go bad in such a short period of time? Something I also noticed in a previous led-staircase-light repair that also did quit working long before a reasonable use of time.
And I therefore do hope that my friends new Optonica replacement led bar doesn’t also suffer the same led problem in time!
Stay safe and always keep in mind that the led bar in this repair is directly connected to the unsafe 230VAC power line!
Until another repair.
Albert van Bemmelen, Weert, The Netherlands.
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Note: You can read his previous article on Repair of 31 Year Old Samsung Microwave Oven