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LG 42ln5300 - Only 1 HDMI Input Work

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    LG 42ln5300 - Only 1 HDMI Input Work

    Bought this TV for $10 with original symptom of no power every now and again but other times powers on fine.

    Did some research and found that many LG sets suffer from bad solder connections under the BGA processor so I reflowed it using a hot air station with lots of flux to the point where I could nudge the chip to confirm all solder had become liquid.

    That got the set turning on everytime but now noticing that only HDMI 2 works and HDMI 1 stays at “no signal”

    Both lead to the main processor that I reflowed, would it still be a bad solder connection or something else?

    Here’s a photo I found of the exact mainbord in my set. Currently have it assembled and since one HDMI works for now don’t have any urgency to take it apart again but I’m curious on any feedback or possibly someone that encountered same issue and resolved it so if HDMI 2 stops working I know where to start looking
    Attached Files
    Last edited by caphair; 02-21-2018, 11:24 AM.

    #2
    Re: LG 42ln5300 - Only 1 HDMI Input Work

    Yes this would most likely be a processor problem. Check to make sure all solder connections on the other H DMI port that is not working are properly making connection
    Did I leave the soldering iron on?

    Comment


      #3
      Re: LG 42ln5300 - Only 1 HDMI Input Work

      The processor just shorted out randomly while the tv was on. Can these be purchased or entire board needs replacing?

      Comment


        #4
        Re: LG 42ln5300 - Only 1 HDMI Input Work

        Originally posted by caphair View Post
        The processor just shorted out randomly while the tv was on. Can these be purchased or entire board needs replacing?
        Yes, they can be bought separately, they are attached by BGA though.

        Comment


          #5
          Re: LG 42ln5300 - Only 1 HDMI Input Work

          Originally posted by diif View Post
          Yes, they can be bought separately, they are attached by BGA though.
          Do you know where they can be purchased?

          Comment


            #6
            Re: LG 42ln5300 - Only 1 HDMI Input Work

            Originally thought this was a backlight issue so I removed the panel and tested the leds. Quesiton, if there were fingerprints on the back of the panel that weren’t wiped off. Will they be visible with the set running?

            Comment


              #7
              Re: LG 42ln5300 - Only 1 HDMI Input Work

              I've bought them from Aliexpress, it's possible the fingerprints are visible, I wear nitrile gloves when I am moving screens to avoid any issues.

              Comment


                #8
                Re: LG 42ln5300 - Only 1 HDMI Input Work

                Originally posted by caphair View Post
                Originally thought this was a backlight issue so I removed the panel and tested the leds. Quesiton, if there were fingerprints on the back of the panel that weren't wiped off. Will they be visible with the set running?
                Finger prints, dust and whatever sticks to the inside of the screen and diffuser screens via static.

                I always wear nitrile gloves as well - right after i remove the plastic bezel to prevent any issues. I had finger prints on the first panel i took apart but only noticed it after i reassembled the entire thing.
                -Thomas
                I'm a hardware engineer focused on networking equipment for my day job. I void warranties and fix consumer electronics for fun.

                Comment


                  #9
                  Re: LG 42ln5300 - Only 1 HDMI Input Work

                  So I found an exact main board replacement on eBay cheap which I purchased. Now with the new one I have different symptoms. No flashing standbylight, no light at all actually and the only voltages I measure now are the two 3.3v.

                  With my original mainboard I get all voltages 3.3v 3.3v 12v 12v and 24v and the standby light would flash twice before going out completely. No backlight flicker at all with either mainboards. Possible I purchased a faulty mainboard?
                  Last edited by caphair; 12-28-2019, 05:12 PM.

                  Comment


                    #10
                    Re: LG 42ln5300 - Only 1 HDMI Input Work

                    Sounds like the new board is not sending out the PS-ON signal to turn on the rest of the power supplies.
                    You need to check the Voltage on all the pins of the power supply connector that goes to the main board to see what are there and not there.
                    Never stop learning
                    Basic LCD TV and Monitor troubleshooting guides.
                    http://www.badcaps.net/forum/showthr...956#post305956

                    Voltage Regulator (LDO) testing:
                    http://www.badcaps.net/forum/showthr...999#post300999

                    Inverter testing using old CFL:
                    http://www.badcaps.net/forum/showthr...er+testing+cfl

                    Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                    http://s807.photobucket.com/user/budm/library/

                    TV Factory reset codes listing:
                    http://www.badcaps.net/forum/showthread.php?t=24809

                    Comment


                      #11
                      Re: LG 42ln5300 - Only 1 HDMI Input Work

                      I’m missing the 12v and 24v rails with the replacement

                      Comment


                        #12
                        Re: LG 42ln5300 - Only 1 HDMI Input Work

                        Originally posted by caphair View Post
                        I’m missing the 12v and 24v rails with the replacement
                        We know you are not getting 12v/24v. no PS-ON = no 12V/24V, that is typical topology.
                        But how about the Voltages I am asking for on the power supply connector? We need to know what the Voltages are on the power supply connector that goes to the main board. Read my post #10 again.
                        You should read the LCD TV basic troubleshooting to understand what are required for the TV to work.
                        Show us the pictures of the whole backside of the TV showing how all the boards are connected, then good clear straight shot of the power supply board, the connector should be labeled to tell you what each pin is for.
                        Last edited by budm; 12-28-2019, 07:12 PM.
                        Never stop learning
                        Basic LCD TV and Monitor troubleshooting guides.
                        http://www.badcaps.net/forum/showthr...956#post305956

                        Voltage Regulator (LDO) testing:
                        http://www.badcaps.net/forum/showthr...999#post300999

                        Inverter testing using old CFL:
                        http://www.badcaps.net/forum/showthr...er+testing+cfl

                        Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                        http://s807.photobucket.com/user/budm/library/

                        TV Factory reset codes listing:
                        http://www.badcaps.net/forum/showthread.php?t=24809

                        Comment


                          #13
                          Re: LG 42ln5300 - Only 1 HDMI Input Work

                          Ok here are some pics. Best I could do right now with lighting. Let me know if you need clearer ones I'll try during the day.
                          Attached Files

                          Comment


                            #14
                            Re: LG 42ln5300 - Only 1 HDMI Input Work

                            https://www.badcaps.net/forum/attach...1&d=1577585031
                            The exposed pins you can see from the top side of the board are the odd number pins (Left column of the pin's chart). To measure the EVEN number pins you will need to use skinny probe to probe the connector at the wire entrance side of the connector, but for now we are interesting in the PWR-ON pin.
                            As you can see, the pin with the black dot is pin one and it is corresponding to 'PWR-ON' (same as PS-ON), it should be around 3VDC for the 12V/24V power supplies to turn on.
                            Last edited by budm; 12-28-2019, 08:18 PM.
                            Never stop learning
                            Basic LCD TV and Monitor troubleshooting guides.
                            http://www.badcaps.net/forum/showthr...956#post305956

                            Voltage Regulator (LDO) testing:
                            http://www.badcaps.net/forum/showthr...999#post300999

                            Inverter testing using old CFL:
                            http://www.badcaps.net/forum/showthr...er+testing+cfl

                            Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                            http://s807.photobucket.com/user/budm/library/

                            TV Factory reset codes listing:
                            http://www.badcaps.net/forum/showthread.php?t=24809

                            Comment


                              #15
                              Re: LG 42ln5300 - Only 1 HDMI Input Work

                              Originally posted by budm View Post
                              https://www.badcaps.net/forum/attach...1&d=1577585031
                              The exposed pins you can see from the top side of the board are the odd number pins (Left column of the pin's chart). To measure the EVEN number pins you will need to use skinny probe to probe the connector at the wire entrance side of the connector, but for now we are interesting in the PWR-ON pin.
                              As you can see, the pin with the black dot is pin one and it is corresponding to 'PWR-ON' (same as PS-ON), it should be around 3VDC for the 12V/24V power supplies to turn on.
                              Ok and the mainboard provides this 3.3v right? So the mainboard has a fault?

                              Comment


                                #16
                                Re: LG 42ln5300 - Only 1 HDMI Input Work

                                Main board control that PWR-ON (PS-ON) line.
                                So beside not having PS-ON, what other control signals are you missing?
                                Never stop learning
                                Basic LCD TV and Monitor troubleshooting guides.
                                http://www.badcaps.net/forum/showthr...956#post305956

                                Voltage Regulator (LDO) testing:
                                http://www.badcaps.net/forum/showthr...999#post300999

                                Inverter testing using old CFL:
                                http://www.badcaps.net/forum/showthr...er+testing+cfl

                                Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                http://s807.photobucket.com/user/budm/library/

                                TV Factory reset codes listing:
                                http://www.badcaps.net/forum/showthread.php?t=24809

                                Comment


                                  #17
                                  Re: LG 42ln5300 - Only 1 HDMI Input Work

                                  Also missing PDIM and DRV-ON. Do those come on when PWR-ON is high?

                                  Comment


                                    #18
                                    Re: LG 42ln5300 - Only 1 HDMI Input Work

                                    They are separated signals.
                                    Bottom line: Your replacement board is bad.
                                    Never stop learning
                                    Basic LCD TV and Monitor troubleshooting guides.
                                    http://www.badcaps.net/forum/showthr...956#post305956

                                    Voltage Regulator (LDO) testing:
                                    http://www.badcaps.net/forum/showthr...999#post300999

                                    Inverter testing using old CFL:
                                    http://www.badcaps.net/forum/showthr...er+testing+cfl

                                    Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                    http://s807.photobucket.com/user/budm/library/

                                    TV Factory reset codes listing:
                                    http://www.badcaps.net/forum/showthread.php?t=24809

                                    Comment


                                      #19
                                      Re: LG 42ln5300 - Only 1 HDMI Input Work

                                      Originally posted by budm View Post
                                      They are separated signals.
                                      Bottom line: Your replacement board is bad.
                                      Can it be repaired or does this indicate an issue with the microprocessor?

                                      Have another question, found the exact main board but for a 50” lcd half the price even though all components and placement are identical. If I swap eeproms would it work for my 42”?

                                      Comment


                                        #20
                                        Re: LG 42ln5300 - Only 1 HDMI Input Work

                                        Eeprom there, looks like a match: https://www.shopjimmy.com/lg-42ln530...eprom-only.htm

                                        Comment

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