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LG 55EC930V OLED - swich on swich of no screen

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    LG 55EC930V OLED - swich on swich of no screen

    My Oled Tv is 55inch tv, 3 days ago I notice that middle of the screen is getting warmer and on picture I have ghosting, missing red color. Color red was still displaying, but it was not so strong as corners of the screen and watching some movies makes me angry.
    Then I get an idea to take it apart and clean boards from dust.
    In side of Tv was not so bad, I take compressed air in can, and gently blow up.

    Also I was thinking to styrofoam sponge to isolate power board from screen that the middle of the screen will not worm so much. Because Led on screen when gets higher temperature, its working resistance gets change, and that could affect difference on displaying red color.

    Broads I put back, screwed it, aaaand connect to power wall socket... I try turn on and I noticed it not happened nothing, I check back of tv why didnt turn on, and I noticed that I forget connect power cables to the boards... Ohhh... On cable connected to power wall I take cables from power board and connect first to main board, and then second one to T-CON board. I check one more time all cables if they was properly connected, and I try turn on TV.
    And with my surprise, I get white line on top of screen, and then black. Like Tv did shut down. I was so upset of what did happened. I start thinking what I did wrong that I broke my tv. At first first thought i think that it was spike of voltage from power board to main board when I was connecting power to boards...

    Now from reading posts on this site, watching Youtube... A lot of Youtube... After making bunch of testing and voltage reading, I find out that Voltage spike is not so possible, because when power board dont get signal to turn on, he don't provide 12 and 24V to main board. is 0V, only stand by voltage is existing. And I start looking for other possibilities.

    Yes, I disconnected all boards from power board, and I check voltages on standby mode.
    All was ok. Then Like on another forum was mentioned, I bay pas function of turn on, I put 1Kohm to PWR_ON and DRV_ON, and I check voltages, And looks good.
    23.8V, 11,6V, and for TCON 24V+-. Then First assumption is that Power board works good.

    Then I go to main board. I connected it to power board, and I try usb wih mp4 movie on second usb input, some peoples said that sometimes helps start board, or just to hear sound if board is working. problem is that my usb stick have led indication if is readed from, and that light was not showing up.
    Then I try use one of push buttons on the board to turn on. After doing that steps and hearing 3 times on of, it starts. Power to board with voltages 12V and 24V was correct, no noticed any voltage drop. But Usb did just fast blink, and that's all... Nothing more.

    I connected also pc on HDMI port, where alwas was connected, On this port before I brake it, Tv was working on. Also nothing. No sound.

    I try another Idea about hard turn on, and disconnect from power wall, but I think this don't have sense, because board have big capacitors, and I noticed that board is going to turn of state when he noticed that power go out. And they are storing enough voltage to sustain stand by mode for a while. Anyway, I try it few times, and didn't help, also when I connected back TCON.

    Then I focused on Tcon board. I check voltages on turning on state. there voltage rise to almost 24V and turns of... First My assumption was, maybe there is shortage on board on TCON Board? I check board visually and nothing, I check resistance with multi-meter on side where 24V is supplied, also nothing. Then I get Idea to bypass turn on power board with 1Kohm. I disconnected main board and I put resistors in to socked. I check voltage on TCON, and ..... There was nice steady 24V. I keep that for a while to check if some elements are heating on... Nothing, board was cold.
    That Means that power supply for led screen is good.

    Then I found out where is fuse on TCON, And I check that, fuse also is good. There gows 12V and is steady. " I want mention that this model OLED have separate power to processor on TCON and separate power going to screen. Means that TCON stripe don't power screen it self, is powering only processor...

    Ps, I forget mention that Main board have led indicator which check if TCON send signal if is working or not, and That led is shining on red. I trace that led connection and one of the traces go straight to TCON board. Normally transistor is powered from main board with something 2.3V, But connection from TCON is shortening to ground, and this way, main board knows what is going. Question is if that signal , that red light is good sign or not?

    -I still could not figure out which board is broken. Or there are two ones bad?
    -Also I dont know if main board can work alone without connecting TCON in this model.

    When I try start on with remote or button from Tv on cold board, the screen is dark, but when I turn main board on push button on board, main board processor is warming on, also TCON processor, is warming. And then with remote I turn of and try turn on, I get white strip on top of screen. When Board cools down, white strip is not displaying any more. This strip looks like it treys draw lines 2 times.

    In the dark room before I try disconnect main board strip from TCON and this way power on, I see little light on whole screen, but after one second tv turn of...

    Last thing what it can come to my mind is If processor on main board have cold or broken connections? And need re solder?? <- this I scared the most.

    I did already order new boards for main board and TCON, But when i wait for board to arrive, Stil I am fighting with that problem.

    Ps, I dont have old phone to be able do service remote...

    Please HELP

    #2
    Re: LG 55EC930V OLED - swich on swich of no screen

    I try one more time with tcon board. And I found something strange in voltage. One of coils should have output of 1.15v but there was 0.3v. Then I check capacitors, all of them was good. Then I dismount coil it self, because I was not sure if one of voltage regulators say blown. No there are good ones.
    When I check resistance of input of the coil and output without mounted any of that capacitors on that place, I found that output is 26ohms. Now I don't know where that output is going to. I will catch pictures of that board.

    I hope that it is not going to memory or process it self.
    Attached Files

    Comment


      #3
      Re: LG 55EC930V OLED - swich on swich of no screen

      What is the part number of US2 (or it could be U62) and Q17 and Q23
      Willing to help but I'm no expert.

      Comment


        #4
        Re: LG 55EC930V OLED - swich on swich of no screen

        Originally posted by dick_barton View Post
        what is the part number of us2 (or it could be u62) and q17 and q23
        US2 - 0a=1e 62r

        q17 - m9c025 1137 1437b1

        q23 is this same.
        Last edited by maxim2511; 05-14-2021, 06:53 AM.

        Comment


          #5
          Re: LG 55EC930V OLED - swich on swich of no screen

          This part have strange number.
          Attached Files

          Comment


            #6
            Re: LG 55EC930V OLED - swich on swich of no screen

            Can't seem to find anything with those numbers.
            Willing to help but I'm no expert.

            Comment


              #7
              Re: LG 55EC930V OLED - swich on swich of no screen

              Originally posted by dick_barton View Post
              Can't seem to find anything with those numbers.
              I know. Me too. But I did more testing at that place, and I do trick to light on screen for that second, and That place where I was thinking is bad, show me 1.0V, and I think is enough good. In stand by mode that voltage is lower to 0.9V.

              Then The problem must lied somewhere else.



              If I disconnect TCON in working tv, do main board should work normally? Or is detecting that Tcon board is missing and anyway will not turn on? I mean, if main board can work without TCON conected to it?


              Q17 and Q23 are logic NMosfet. I tested resistance in that two of them, and are this same, that mean those two are workig.
              Last edited by maxim2511; 05-14-2021, 07:09 AM.

              Comment


                #8
                Re: LG 55EC930V OLED - swich on swich of no screen

                Some Tcons have feedback to the mainboard. It looks like this Tcon does looking at the number of connectors it has. CN1, CN7 and CN13

                Have you tried disconnecting CN9 cable from the tcon to the panel then power up to check if the set will come on. Then power back down and reconnect CN9 and disconnect CN10 and power up again. Repeat for all 4 connectors CN9, CN10, CN11 & CN12
                Last edited by dick_barton; 05-14-2021, 07:15 AM.
                Willing to help but I'm no expert.

                Comment


                  #9
                  Re: LG 55EC930V OLED - swich on swich of no screen

                  Originally posted by dick_barton View Post
                  Some Tcons have feedback to the mainboard. It looks like this Tcon does looking at the number of connectors it has. CN1, CN7 and CN13

                  Have you tried disconnecting CN9 cable from the tcon to the panel then power up to check if the set will come on. Then power back down and reconnect CN9 and disconnect CN10 and power up again. Repeat for all 4 connectors CN9, CN10, CN11 & CN12
                  Yes, i did that, no change. I read on another post on this site that Oled tv is not working like normal lcd displays, and this could not work. Anyway I try it and no change. I disconnected them all also, no change.

                  Comment


                    #10
                    Re: LG 55EC930V OLED - swich on swich of no screen

                    Yes, I realised just after I posted it that it was an OLED and not an LCD panel.
                    Willing to help but I'm no expert.

                    Comment


                      #11
                      Re: LG 55EC930V OLED - swich on swich of no screen

                      Originally posted by dick_barton View Post
                      Yes, I realised just after I posted it that it was an OLED and not an LCD panel.
                      No problem,

                      Comment


                        #12
                        Re: LG 55EC930V OLED - swich on swich of no screen

                        Originally posted by maxim2511 View Post
                        Yes, i did that, no change. I read on another post on this site that Oled tv is not working like normal lcd displays, and this could not work. Anyway I try it and no change. I disconnected them all also, no change.
                        I just find video on Youtube that somebody get hand on Oled tv and He had also problem with not turning on tv.
                        https://www.youtube.com/watch?v=qpCO49sDznI
                        on this movie now I get clue for my question, doo main board will work if I will disconect TCON board from main board. And Yes! It should work.
                        That means that I have problem in main board, because still is turning of .

                        Do anybody knows where I can start looking for issue in main board?

                        Comment


                          #13
                          Re: LG 55EC930V OLED - swich on swich of no screen

                          what about tpss3513 TI 481 CE8S
                          This part is on main board, and is close to coil, that coil is showing me 0.9V, but higher place there is 11.6V, yeah, almost 12V . I think this go to main procesor. When I put main board on hard turn on using botton on board, procesor is heating on like it could working, but I dont see light from optical fiber.. Coil it self is quite big, and so smal voltage is wired for that big coil.

                          Comment


                            #14
                            Re: LG 55EC930V OLED - swich on swich of no screen

                            There where is white arrow, is pointing straight to that coil. I am wondering that for me 0.9v is bit too low. I think it should be more then 5v?

                            I read PDF about that chip, and this is Buck converter. Is step down voltage. PDF say that output should be something 0.6 to 5.5v but that big coil. Hm..

                            Capacitor near that coil have 0.26ohm.

                            Also I notice that when I try turn on with remote, that coil have 0.9V, and then goes to 0V, like is switching of earlier and then I heard click from power board.
                            Attached Files
                            Last edited by maxim2511; 05-14-2021, 01:21 PM.

                            Comment


                              #15
                              Re: LG 55EC930V OLED - swich on swich of no screen

                              I am thinking about that 11.4V if is not too low? Someone have experience with oled tv?
                              Also nice will be to get some pdf with testing points on board, maybe will be easier to find something unusuale.
                              Last edited by maxim2511; 05-14-2021, 03:40 PM.

                              Comment


                                #16
                                Re: LG 55EC930V OLED - swich on swich of no screen

                                Somebody knows what is remote ir code for IN_START ?
                                I found post about IN_STOP code, but for my tv is not working. I want try wit IN_START

                                Post about codes for LG tv is https://www.badcaps.net/forum/showthread.php?t=92649

                                Comment


                                  #17
                                  Re: LG 55EC930V OLED - swich on swich of no screen

                                  Diah has posted this several times on this forum. I have never tried it.
                                  Attached Files
                                  Willing to help but I'm no expert.

                                  Comment


                                    #18
                                    Re: LG 55EC930V OLED - swich on swich of no screen

                                    I try do it with arduino and IR diode, But didn't work. I think first I need have working main board for that. Because problem with IR was described when Main board was working, but TCON didn't display nothing. And to force to read eeprom, they use usb mouse, or usb stick with some movie. And in_stop In_start was used to break safe mode...
                                    I think so...
                                    Maybe I am wrong, but trying arduino didnt work, or I have bad codes used for different LG tv.

                                    For now I cant boot main board, and yesterday I found out that TCON i can have disconnected, and main board should work. And still I cant find solution to boot that board.
                                    Last edited by maxim2511; 05-15-2021, 02:14 PM.

                                    Comment


                                      #19
                                      Re: LG 55EC930V OLED - swich on swich of no screen

                                      I did order new boards, and Broken was TCON... Now I have different problem, and this is probably not problem of new TCON, I have almost black shadow in t he middle of the screen. It looks like there is not enough voltage, because when I have menu from operating system, and the rest is black screen, then letters are quite white, but when All screen is white, then whole screen is darkening, and in the middle of the screen is dark shadow. What more wired, is that when I change input from HDMI to 3, then is a lot worse.
                                      Screen should work a lot better, because ealier I was watching tv. From time when I was waiting for new boards, is NOT possible that pixels could burn out!
                                      I check voltage going to power screen in TCON from power board, and voltage is 23,6V not 24V.
                                      Maybe ground is missing?
                                      When TV works for longer time, then middle of the creen is going even more darker. But when I switch input in HDMI to 2 port, for short moment screen looks a lot better.



                                      What I can check??


                                      PS: Now I have 2 working main boards, and one TCOM from different TV but exactly this same model.
                                      Last edited by maxim2511; 05-17-2021, 11:39 AM.

                                      Comment


                                        #20
                                        Re: LG 55EC930V OLED - swich on swich of no screen

                                        OMG I think I figure out problem of ghosting on the oled screen. I am in shock. You will be also when You find out that. I will attach screen shot of that problem. Probably is overheated picture processor on the main board.

                                        Comment

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