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    Repairing cheap chinese Led bulbs

    Hello,

    I'd like to try to repair these corncob shaped chinese bulbs with tens of Leds on them.

    I know they're bad quality and fail fast, because of the Leds or the capacitor(s).
    So I plan to try to replace the main capacitor 15uF-400V with a good quality one.

    I've used in the past some capacitors of this eBay vendor which is well known on this site: egekecu. I'm still daily using a monitor I repaired with his products.
    I know it has been said he sells good and real brands but outdated capacitors. He's actually 3 times cheaper than RS-Online so... I think I'll choose him for now.

    My problem is that he doesn't sell exactly 15uF-400V capacitors. But he has, for example:

    15uF-450V
    10uF-450V
    22uF-450V
    10uF-400V
    22uF-400V

    ...and many others.

    I don't know which ones I should ideally get for replacement.

    http://www.ebaystores.com/PC-MotherB...pacitors-Store

    Voltage here is 240V.

    Thanks for any advice !

    #2
    Re: Repairing cheap chinese Led bulbs

    i like to use Rubycon LLE for mains stuff.
    450v is better, if it will fit
    Attached Files

    Comment


      #3
      Re: Repairing cheap chinese Led bulbs

      Rubycon BXC series 450V-15uF are the only 450V-15uF capacitors in egekecu store, so I don't have much choice on these.

      Thanks.

      Comment


        #4
        Re: Repairing cheap chinese Led bulbs

        It will be 240V or similar, for me, if I use the plug near my bedroom, where there was a range, LOL.
        ASRock B550 PG Velocita

        Ryzen 9 "Vermeer" 5900X

        16 GB AData XPG Spectrix D41

        Sapphire Nitro+ Radeon RX 6750 XT

        eVGA Supernova G3 750W

        Western Digital Black SN850 1TB NVMe SSD

        Alienware AW3423DWF OLED




        "¡Me encanta "Me Encanta o Enlistarlo con Hilary Farr!" -Mí mismo

        "There's nothing more unattractive than a chick smoking a cigarette" -Topcat

        "Today's lesson in pissivity comes in the form of a ziplock baggie full of GPU extension brackets & hardware that for the last ~3 years have been on my bench, always in my way, getting moved around constantly....and yesterday I found myself in need of them....and the bastards are now nowhere to be found! Motherfracker!!" -Topcat

        "did I see a chair fly? I think I did! Time for popcorn!" -ratdude747

        Comment


          #5
          Re: Repairing cheap chinese Led bulbs

          What do those corncob LEDs use those 15uF capacitors for, just filtering or is there actually a CC SMPS in the LED? I was under the impression a lot of the corncob LEDs use capacitive droppers which don't do much to those capacitors... and most of the failures were caused by LEDs going OC?

          Comment


            #6
            Re: Repairing cheap chinese Led bulbs

            the electrolytic on capacitive droppers is to stop flicker - which can be bad on the cob style ones!

            Comment


              #7
              Re: Repairing cheap chinese Led bulbs

              Upload a photo of the bulb, so that we know what we're dealing with. Am I right thinking you're talking about G5-type bulbs (see attachment)?

              Before you start swapping caps, first check if all LED's are OK. Only 1 burnt LED will prevent the entire bulb from working.

              A few years ago I had 2 G5 LED bulbs die on me within two weeks. My bulbs each had 36 LED's, one bulb contained 2 (plainly visible) burnt LED's, the other had 1 burnt LED. I replaced the burnt ones with LED's ordered on AliExpress, both bulbs have worked without a problem ever since. It was a bit tricky getting the LED's (de)soldered, but it turned out OK.

              Do make sure you replace the LED's with matching ones (V, mA, color temp, casing dimensions).

              re-atari
              Attached Files

              Comment


                #8
                Re: Repairing cheap chinese Led bulbs

                Yeah perhaps flicker is worse in 50Hz land but the cobs would at least still light up I would think? Also 50Hz is ezpz to filter and doesn't stress caps as much.

                But what surprised me more is people would call flickering a "failure" versus it not lighting up at all...

                Comment


                  #9
                  Re: Repairing cheap chinese Led bulbs

                  well i think we are talking about the big ones - 10-20w type.
                  if those were strobing at 100Hz or alternating between 2 banks at 50Hz it would be pretty unbearable.

                  Comment


                    #10
                    Re: Repairing cheap chinese Led bulbs

                    I'd rather see "interlaced" strobing at 50Hz than being in the dark at 0Hz...

                    Comment


                      #11
                      Re: Repairing cheap chinese Led bulbs

                      Hello,

                      Thanks for all your answers ! I'll try to respond to everybody.

                      I've used several kinds of these Leds bulbs for years. The best I know (and the ones I have used most) are these:

                      https://fr.aliexpress.com/item/32777936012.html

                      and especially the 20W/99leds model which seems to last the longer (from about 3 months to 2 years and maybe more, we'll see).

                      I use E27, E14 and sometimes B22 sockets, never G5.
                      It's 240V/60Hz in my country.

                      I don't know what the capacitors are there for, I really don't know much in electronics.

                      I'm aware that 1 burnt led can prevent the whole lamp to work, but I think it depends on the location of the failing led(s). Maybe I'll try to replace some as well; to me it just seems a little bit trickier than the caps replacement, and I can find dead lamps with no burnt leds in my stock, to begin my tests with caps.

                      I have a lot of dead or partially dead lamps, not all with the same symptoms. So I have all the material I want to swap leds.

                      Why do I use these lamps if they fail so quickly for the most part ? Because old house (so, old lamps, not willing to change all the lighting), big rooms, so need of very powerful lighting in each floor lamp or table lamp. Sometimes, I even use socket splitters to connect two or three 20W-leds bulbs in one floor lamp.

                      I have attached pictures of a PCB with both capacitors unbent for more clarity.

                      So, which caps should I try ?
                      And by the way, should I replace both of them ?

                      The big one is 15uF/400V,
                      The small one is 2.2uF/400V)

                      Thanks again !
                      Attached Files

                      Comment


                        #12
                        Re: Repairing cheap chinese Led bulbs

                        a real psu - nice!
                        so the caps need to be low impedence type
                        the output one does anyway - but i cant tell which that is from the pictures.

                        Comment


                          #13
                          Re: Repairing cheap chinese Led bulbs

                          Originally posted by blero View Post
                          Hello,
                          I've used several kinds of these Leds bulbs for years. The best I know (and the ones I have used most) are these:

                          https://fr.aliexpress.com/item/32777936012.html

                          and especially the 20W/99leds model which seems to last the longer (from about 3 months to 2 years and maybe more, we'll see).

                          I use E27, E14 and sometimes B22 sockets, never G5.
                          It's 240V/60Hz in my country.
                          Those look like my G5 bulbs, but heavily on steroids
                          Looks like (de)soldering LED's on these will be quite a challenge, as the advert says the bulbs have aluminium PCB's.

                          re-atari

                          Comment


                            #14
                            Re: Repairing cheap chinese Led bulbs

                            Originally posted by blero View Post
                            It's 240V/60Hz in my country.
                            That outlet near my bedroom, might be that other transformer configuration type, it might be a 208 which means a wye/"star" transformer, IIRC. Won't know, unless I can do a voltage test with a multimeter.

                            With the luck I seem to have, it possibly will be ((rating)-subtract 2 volts) (Thus, if I get "206", it's a 208)
                            Last edited by RJARRRPCGP; 02-03-2021, 12:40 AM.
                            ASRock B550 PG Velocita

                            Ryzen 9 "Vermeer" 5900X

                            16 GB AData XPG Spectrix D41

                            Sapphire Nitro+ Radeon RX 6750 XT

                            eVGA Supernova G3 750W

                            Western Digital Black SN850 1TB NVMe SSD

                            Alienware AW3423DWF OLED




                            "¡Me encanta "Me Encanta o Enlistarlo con Hilary Farr!" -Mí mismo

                            "There's nothing more unattractive than a chick smoking a cigarette" -Topcat

                            "Today's lesson in pissivity comes in the form of a ziplock baggie full of GPU extension brackets & hardware that for the last ~3 years have been on my bench, always in my way, getting moved around constantly....and yesterday I found myself in need of them....and the bastards are now nowhere to be found! Motherfracker!!" -Topcat

                            "did I see a chair fly? I think I did! Time for popcorn!" -ratdude747

                            Comment


                              #15
                              Re: Repairing cheap chinese Led bulbs

                              Originally posted by RJARRRPCGP View Post
                              That outlet near my bedroom, might be that other transformer configuration type, it might be a 208 which means a wye/"star" transformer, IIRC. Won't know, unless I can do a voltage test with a multimeter.

                              With the luck I seem to have, it possibly will be ((rating)-subtract 2 volts) (Thus, if I get "206", it's a 208)
                              Why would you have 208 volts on one of your outlets in bedroom am I missing something here because most house have 120 / 240 volts unless you have 3 phases power but if that is the case then the question is why

                              Unless it is a business environment that I would understand but in house setting I am confused about what you have posted above

                              Is the power company in your area give you s**t-e power because where I live my voltage is sometimes very unstable by any where 2 to 6 volts moment by moment and sometimes even more of a spread than that

                              The cycles do not very not more 1 to 2 HZ at the most of the time when I have measured it
                              Last edited by sam_sam_sam; 02-03-2021, 01:09 AM.
                              9 PC LCD Monitor
                              6 LCD Flat Screen TV
                              30 Desk Top Switching Power Supply
                              10 Battery Charger Switching Power Supply for Power Tool
                              6 18v Lithium Battery Power Boards for Tool Battery Packs
                              1 XBox 360 Switching Power Supply and M Board
                              25 Servo Drives 220/460 3 Phase
                              6 De-soldering Station Switching Power Supply 1 Power Supply
                              1 Dell Mother Board
                              15 Computer Power Supply
                              1 HP Printer Supply & Control Board * lighting finished it *


                              These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                              1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                              2 Hem Saw Computer Stack Board

                              All of these had CAPs POOF
                              All of the mosfet that are taken out by bad caps

                              Comment


                                #16
                                Re: Repairing cheap chinese Led bulbs

                                Originally posted by sam_sam_sam View Post
                                Why would you have 208 volts on one of your outlets in bedroom am I missing something here because most house have 120 / 240 volts

                                Unless it is a business environment that I would understand but in house setting I am confused about what you have posted above
                                The outlet I'm talking about, is near the bedroom, just some feet away, where there was a range, I believe.

                                IIRC, I interestingly, saw a YT video where a range outlet, was a 208!
                                "206" on the multimeter. So I just wondered, LOL.
                                Last edited by RJARRRPCGP; 02-03-2021, 01:03 AM.
                                ASRock B550 PG Velocita

                                Ryzen 9 "Vermeer" 5900X

                                16 GB AData XPG Spectrix D41

                                Sapphire Nitro+ Radeon RX 6750 XT

                                eVGA Supernova G3 750W

                                Western Digital Black SN850 1TB NVMe SSD

                                Alienware AW3423DWF OLED




                                "¡Me encanta "Me Encanta o Enlistarlo con Hilary Farr!" -Mí mismo

                                "There's nothing more unattractive than a chick smoking a cigarette" -Topcat

                                "Today's lesson in pissivity comes in the form of a ziplock baggie full of GPU extension brackets & hardware that for the last ~3 years have been on my bench, always in my way, getting moved around constantly....and yesterday I found myself in need of them....and the bastards are now nowhere to be found! Motherfracker!!" -Topcat

                                "did I see a chair fly? I think I did! Time for popcorn!" -ratdude747

                                Comment


                                  #17
                                  Re: Repairing cheap chinese Led bulbs

                                  This would be weird if that would be the case and I would be lol myself

                                  All though I could see how this might happen if you were a long way from the the power poll from the the street and had a very large voltage drop that was my problem when I first move into the house that I live in now I am more than 250 feet from the road I do have a transformer for my house and I am the only one on it

                                  When I move in the power line had to be put under ground and the power company could not put power poll in property so drop from the transformer is to very long

                                  Now they have reversed this decision and now they allow this to be done again

                                  I would have voltages 106 volts at times and this would with out the air conditioning unit running and with the air conditioning on it would some time drop a few volts more

                                  And when the compressor would start it would drop down below 100 volts and the light would dim down almost nothing for at least a second or so

                                  I had the power company come out and change the tap on the transformer up one and now I have the opposite problem now my voltage is 120 volt to sometimes as high as 128 volts but most of the it is 125 volts

                                  Which I can live with better than it being very low
                                  Last edited by sam_sam_sam; 02-03-2021, 01:37 AM.
                                  9 PC LCD Monitor
                                  6 LCD Flat Screen TV
                                  30 Desk Top Switching Power Supply
                                  10 Battery Charger Switching Power Supply for Power Tool
                                  6 18v Lithium Battery Power Boards for Tool Battery Packs
                                  1 XBox 360 Switching Power Supply and M Board
                                  25 Servo Drives 220/460 3 Phase
                                  6 De-soldering Station Switching Power Supply 1 Power Supply
                                  1 Dell Mother Board
                                  15 Computer Power Supply
                                  1 HP Printer Supply & Control Board * lighting finished it *


                                  These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                                  1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                                  2 Hem Saw Computer Stack Board

                                  All of these had CAPs POOF
                                  All of the mosfet that are taken out by bad caps

                                  Comment


                                    #18
                                    Re: Repairing cheap chinese Led bulbs

                                    Originally posted by sam_sam_sam View Post

                                    I had the power company come out and change the tap on the transformer up one and now I have the opposite problem now my voltage is 120 volt to sometimes as high as 128 volts but most of the it is 125 volts

                                    Which I can live with better than it being very low
                                    In downtown Springfield, across from the town hall, I often saw higher voltages, but they were in totally acceptable spec.

                                    I was there officially from March 5, 2008 to April 15, 2016.

                                    Then the first move was to one with a bad neutral. One outlet with furnace and range running, according to my UPS, went to 132 V and on another outlet, 111 V, (or 112 V) so I found the loaded down leg by accident.
                                    ASRock B550 PG Velocita

                                    Ryzen 9 "Vermeer" 5900X

                                    16 GB AData XPG Spectrix D41

                                    Sapphire Nitro+ Radeon RX 6750 XT

                                    eVGA Supernova G3 750W

                                    Western Digital Black SN850 1TB NVMe SSD

                                    Alienware AW3423DWF OLED




                                    "¡Me encanta "Me Encanta o Enlistarlo con Hilary Farr!" -Mí mismo

                                    "There's nothing more unattractive than a chick smoking a cigarette" -Topcat

                                    "Today's lesson in pissivity comes in the form of a ziplock baggie full of GPU extension brackets & hardware that for the last ~3 years have been on my bench, always in my way, getting moved around constantly....and yesterday I found myself in need of them....and the bastards are now nowhere to be found! Motherfracker!!" -Topcat

                                    "did I see a chair fly? I think I did! Time for popcorn!" -ratdude747

                                    Comment

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