Ubiquitiu 24 port POE. Help Identify Diode 3pin)

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  • gurj1979
    Senior Member
    • Dec 2014
    • 186
    • UK

    #1

    Ubiquitiu 24 port POE. Help Identify Diode 3pin)

    Hi again guys.
    Ive got a Ubiquiti 24 port POE Switch which has failed to work. Fans turn on, but no lights.
    I've ripped the board out, flipped it upside down and noticed a blown 3pin SMD Diode (at location D53). Marking is ESSP (as with all the other Diodes in the same row).

    Anyone help me identify the model of this Diode ?
    Attached Files
  • SMDFlea
    Super Moderator
    • Jan 2018
    • 20453
    • UK

    #2
    Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

    Originally posted by gurj1979
    Hi again guys.
    Ive got a Ubiquiti 24 port POE Switch which has failed to work. Fans turn on, but no lights.
    I've ripped the board out, flipped it upside down and noticed a blown 3pin SMD Diode (at location D53). Marking is ESSP (as with all the other Diodes in the same row).

    Anyone help me identify the model of this Diode ?
    Looks like E5SP (five) to me .

    https://cdn.badcaps-static.com/pdfs/...04da442b01.pdf
    .
    Attached Files
    Last edited by SMDFlea; 08-23-2023, 09:02 AM.
    All donations to badcaps are welcome, click on this link to donate. Thanks to all supporters

    Comment

    • gurj1979
      Senior Member
      • Dec 2014
      • 186
      • UK

      #3
      Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

      Originally posted by SMDFlea
      Looks like E5SP (five) to me .
      .
      You might be right. Terrible laser engraving by manufacturer. lol

      Comment

      • gurj1979
        Senior Member
        • Dec 2014
        • 186
        • UK

        #4
        Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

        I think I found it.

        https://cdn.badcaps-static.com/pdfs/...04da442b01.pdf

        Comment

        • SMDFlea
          Super Moderator
          • Jan 2018
          • 20453
          • UK

          #5
          Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

          Originally posted by gurj1979
          I just added a picture and the same schematic at the same time as you posted

          Last edited by SMDFlea; Today at 04:02 PM..
          .
          All donations to badcaps are welcome, click on this link to donate. Thanks to all supporters

          Comment

          • gurj1979
            Senior Member
            • Dec 2014
            • 186
            • UK

            #6
            Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

            haha snap.
            Thanks for helping.

            Comment

            • gurj1979
              Senior Member
              • Dec 2014
              • 186
              • UK

              #7
              Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

              The SoC is dead short to ground for 1v supply.
              Must have been that ESD Diode that did it.
              Ordered a new one (call it a dead one as always) from AliExpress. ETA 12th Sept.
              Broadcom BCM53344A0KFSBLG

              Comment

              • gurj1979
                Senior Member
                • Dec 2014
                • 186
                • UK

                #8
                Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

                Chip arrived, put it in, worked for a while. Connected Ground strap and chip died again.
                Found that something called Sidactor was shorted, causing voltage to go from 48v to Ground. Got another new CPU. New Sidactor ordered from RS Components. Will try it all out again tomorrow.

                Comment

                • gurj1979
                  Senior Member
                  • Dec 2014
                  • 186
                  • UK

                  #9
                  Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

                  Update - So all that works fine now Happy days.
                  But I noticed Port 12 only works at 10/100 (Orange LED). All other ports work at 1000 (Green LED).

                  Any ideas ?

                  Comment

                  • stj
                    Great Sage 齊天大聖
                    • Dec 2009
                    • 30950
                    • Albion

                    #10
                    Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

                    if the overvoltage protector failed (sidactor?)
                    then i would check all the transformer windings and the related caps and diodes - compare readings to a working one next to it

                    Comment

                    • gurj1979
                      Senior Member
                      • Dec 2014
                      • 186
                      • UK

                      #11
                      Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

                      Looks like Port 12 is linked to LAN Transformer M-TEK G48209SNG.
                      So now I have to out where I can get this or equivalent from in UK. Perhaps RS Components again for quick and cheap price.
                      I'll update when I have some more new. But so far this is looking good.

                      Comment

                      • stj
                        Great Sage 齊天大聖
                        • Dec 2009
                        • 30950
                        • Albion

                        #12
                        Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

                        dont just buy stuff, it could be a bad cap or diode or unfortunatly the chip it all feeds into

                        Comment

                        • gurj1979
                          Senior Member
                          • Dec 2014
                          • 186
                          • UK

                          #13
                          Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

                          Originally posted by stj
                          dont just buy stuff, it could be a bad cap or diode or unfortunatly the chip it all feeds into
                          6 pins (3 each on opposite ends) are giving zero ohms whereas others have high resistance.

                          I will check again for shorted caps but I didn't come across any today. Perhaps use my thermal cam.

                          Comment

                          • stj
                            Great Sage 齊天大聖
                            • Dec 2009
                            • 30950
                            • Albion

                            #14
                            Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

                            that 0 ohms could be the transformer windings,
                            check against the diagram
                            http://en.mag-tek.com.cn/product/264...oductCateId=46

                            Comment

                            • gurj1979
                              Senior Member
                              • Dec 2014
                              • 186
                              • UK

                              #15
                              Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

                              Correct for 3 pins in 1 side, but not on the opposite side. It turns into magnetic inside the transformer, then outputs to the opposite end. None of the other transformers are 0 ohms on opposite ends.
                              I'll check again for caps today in a couple of hours.

                              Comment

                              • gurj1979
                                Senior Member
                                • Dec 2014
                                • 186
                                • UK

                                #16
                                Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

                                Update.
                                I've removed the The M-TEK Lan Tranaformer and one of the coils is burnt to smithereens.
                                See the pic. 2nd coil from left.

                                Now I can't buy this LAN Transformer anywhere in UK, not most of the world.

                                Can someone help me find a suitable replacement ?
                                It's 48 pins, 10/100/1000 POE, Single Port, 350uH.

                                From the datasheets, the left side has 2 pri coils, and right side has 1 sec coil. But most replacements on the market are Dual Ports with coils on opposite sides.
                                If I buy Dual Ports, would it affect the way the switch works ?

                                Thanks for all your help so far.
                                Attached Files

                                Comment

                                • gurj1979
                                  Senior Member
                                  • Dec 2014
                                  • 186
                                  • UK

                                  #17
                                  Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

                                  I've ordered this as it's the nearest thing I could find. Although it's Dual Ports instead of Single Port, I can't how it makes any difference. All the pins match up, the coils are in the exact same order as original, only the casing is larger by a couple of mm. Will try it later today.

                                  https://uk.farnell.com/te-connectivi...-ddd7-00001003

                                  Comment

                                  • gurj1979
                                    Senior Member
                                    • Dec 2014
                                    • 186
                                    • UK

                                    #18
                                    Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

                                    Result. Works a treat. Port 12 now has Green light 1000mbps. Job is a goodun.
                                    See pics for comparison of the 2 LAN Transformers.
                                    Attached Files

                                    Comment

                                    • stj
                                      Great Sage 齊天大聖
                                      • Dec 2009
                                      • 30950
                                      • Albion

                                      #19
                                      Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

                                      nice.
                                      lucky you only needed one, the extra width would envolve cutting the ends off the package.

                                      Comment

                                      • gurj1979
                                        Senior Member
                                        • Dec 2014
                                        • 186
                                        • UK

                                        #20
                                        Re: Ubiquitiu 24 port POE. Help Identify Diode 3pin)

                                        Very true. But I found that port 12 POE doesn't work neither. Works as non-POE. So back to the drawing board. Getting closer though.

                                        Comment

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