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LG UF6450 half screen is black, half is blue/white

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    #21
    Re: LG UF6450 half screen is black, half is blue/white

    The powering for the tcon is being "switched" thru the main board. As suggested, check to see if you are getting anything on the small cable going to the tcon. Go from the result.

    Comment


      #22
      Re: LG UF6450 half screen is black, half is blue/white

      See some of the Voltage test points.
      Attached Files
      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


        #23
        Re: LG UF6450 half screen is black, half is blue/white

        I have the same voltage on both sides of the fuse f1

        Comment


          #24
          Re: LG UF6450 half screen is black, half is blue/white

          Tested each point in the image and have voltage on them

          Comment


            #25
            Re: LG UF6450 half screen is black, half is blue/white

            Originally posted by jskuyper View Post
            Tested each point in the image and have voltage on them
            But what were the readings at those points?
            Willing to help but I'm no expert.

            Comment


              #26
              Re: LG UF6450 half screen is black, half is blue/white

              All volts readings
              Vcc 3.3
              Hvdd 8.07
              Vcc18 1.8
              Vcor 1.215
              Va2 8.2
              Vin 13.1

              Comment


                #27
                Re: LG UF6450 half screen is black, half is blue/white

                How about VDD on the top left of the picture that I marked.
                One of the important Voltage is the AVDD (~ 20V) which I cannot see the test point on the T-CON board, it may be around diode D3 located close to inductor L3 and U2, please check the Voltage there at D3 Cathode.
                http://tvrepairsolution.blogspot.com...lcd-panel.html
                Last edited by budm; 07-08-2020, 09:02 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


                  #28
                  Re: LG UF6450 half screen is black, half is blue/white

                  Originally posted by budm View Post
                  How about VDD on the top left of the picture that I marked.
                  One of the important Voltage is the AVDD (~ 20V) which I cannot see the test point on the T-CON board, it may be around diode D3 located close to inductor L3 and U2, please check the Voltage there at D3 Cathode.
                  http://tvrepairsolution.blogspot.com...lcd-panel.html
                  Vdd is 16.6
                  Could not find avdd including a close photo of the area you are speaking of
                  Attached Files

                  Comment


                    #29
                    Re: LG UF6450 half screen is black, half is blue/white

                    Originally posted by budwich View Post
                    The powering for the tcon is being "switched" thru the main board. As suggested, check to see if you are getting anything on the small cable going to the tcon. Go from the result.
                    I don't see where you did any checks around this connector? Check the labelling around the connector at either the tcon or main board and measure the pins (to ground).

                    Comment


                      #30
                      Re: LG UF6450 half screen is black, half is blue/white

                      Originally posted by jskuyper View Post
                      Here you go
                      it that picture (post 3) with all cabling attached / intact?
                      Last edited by budwich; 07-09-2020, 03:19 PM.

                      Comment


                        #31
                        Re: LG UF6450 half screen is black, half is blue/white

                        Originally posted by budwich View Post
                        it that picture (post 3) with all cabling attached / intact?
                        Yes

                        Comment


                          #32
                          Re: LG UF6450 half screen is black, half is blue/white

                          thanks... not looking right with all cables attached. It would appear that the one on the left (looking at the set) is not connected.

                          further, i asked about getting you to measure the voltages at the small connector / cable coming from the main board to the tcon... no response to this. :-(

                          Comment


                            #33
                            Re: LG UF6450 half screen is black, half is blue/white

                            Originally posted by budwich View Post
                            thanks... not looking right with all cables attached. It would appear that the one on the left (looking at the set) is not connected.

                            further, i asked about getting you to measure the voltages at the small connector / cable coming from the main board to the tcon... no response to this. :-(
                            I added an image and checked voltage on each point and one was 3.5v rest were 1.7V is there another area I should be checking?
                            Attached Files

                            Comment


                              #34
                              Re: LG UF6450 half screen is black, half is blue/white

                              ok... thanks... hmmm. I was expecting higher voltages there... maybe. Other types of sets usually have some form of 12v coming thru seperate connectors from the signal / large flat ribbons. Is there any labelling associated with those pins at the other end (ie. main board)?

                              Comment


                                #35
                                Re: LG UF6450 half screen is black, half is blue/white

                                What are next steps. Tcon or main board?

                                Comment


                                  #36
                                  Re: LG UF6450 half screen is black, half is blue/white

                                  There's a tcon if you want to throw one at it: https://www.tvpartstoday.com/6871L-3...871l-3851f.htm

                                  Comment


                                    #37
                                    Re: LG UF6450 half screen is black, half is blue/white

                                    Put a new tcon and still has the same behavior. Any other suggestions?

                                    Comment


                                      #38
                                      Re: LG UF6450 half screen is black, half is blue/white

                                      Looks like the XDA engine BGA chips are failing pretty regularly, don't know that I would even trust a used mainboard, maybe a repair service with at least a 6 month guarantee, a good question to ask would be how they plan on repairing it but they might not want to tell their methods, seems there is some revised boards but didn't see any, in searching, looks like even the boards that cost as much as 200 dollars+ are sold out.

                                      Comment


                                        #39
                                        Re: LG UF6450 half screen is black, half is blue/white

                                        One site claims these parts will substitute but I would triple check that: Mfg Part Number: EBT64048903 Board Number(s): EAX66703203(10) Substitute Parts: CRB35036401, CRB35036501, EBT64048902, EBU63478202 Compatible Models: LG 55UF6450 UA BUSYLJR

                                        Comment


                                          #40
                                          Re: LG UF6450 half screen is black, half is blue/white

                                          If the tcon board replacement had no effect. Is the next thing to go to is the main board or am I just throwing money away? I see the tcon ribbons attach to another board assuming that is the lcd. Could it just be a bad lcd?

                                          Comment

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