LG OLED55B7V doesn't turn on Help.

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  • markolino
    Senior Member
    • Mar 2020
    • 108
    • Slovenia

    #1

    LG OLED55B7V doesn't turn on Help.

    Hi.

    namely, the TV stayed turned off at the red light overnight.. when I want to turn it on with the remote or physical button, there is a not relay click.. and after 5 seconds a click back. the light is always on, nothing flashes... I opened the TV and played around a bit.. when I disconnected the flat cables that lead from the T-Con of the board to the main board, the TV behaves differently (normally) the red light flashes 3 times and then disappears... the TV remains on.. on the main board the audio output light also lights up. and when I press the buttons on the remote, the light reacts to the remote.. but the screen logically remains black.. now i'm not sure.. is the T-Con broken or the main board? even if I reconnect the two flat cables to the Tcon and disconnect all 4 flat cables leading to the panel, the issue remains in the first cors.. so click.. after 5 seconds back click.. the light is always on.. Has anyone had a similar experience?
    Last edited by markolino; 09-12-2023, 03:16 AM.
  • snme
    Member
    • Feb 2016
    • 26
    • AU

    #2
    Re: LG OLED55B7V doesn't turn on Help.

    Is backlight confirmed?
    Or is the mainboard simply not asking for it?
    Perhaps on various models, the mainboard is responsible for reflecting standby 3v or so in order to ask the power supply to activate more fully.
    Unless you have backlight I would not be messing with the T-Con.

    Comment

    • markolino
      Senior Member
      • Mar 2020
      • 108
      • Slovenia

      #3
      Re: LG OLED55B7V doesn't turn on Help.

      after all, we are talking about OLED panels, not LEDs.... so the backlight does not exist on my TV

      Comment

      • snme
        Member
        • Feb 2016
        • 26
        • AU

        #4
        Re: LG OLED55B7V doesn't turn on Help.

        Well, if so, is there any sign that the mainboard directs the power supply to do anything at all, upon notional press of power on?
        Gee I might have to learn more about OLED!
        Just thought that they were darker forms of LED...

        Comment

        • markolino
          Senior Member
          • Mar 2020
          • 108
          • Slovenia

          #5
          Re: LG OLED55B7V doesn't turn on Help.

          all voltages are present for 5 seconds..
          but if I disconnect the 2 LVDS cables that go from the T-Con to the green main board, then things change.
          the tv turns on, all the voltages are present... the red light flashes when I press the remote. for example volume UP/Down... and the light on the optical connector also lights up

          Comment

          • snme
            Member
            • Feb 2016
            • 26
            • AU

            #6
            Re: LG OLED55B7V doesn't turn on Help.

            I am aware that there can be some forms of feedback.
            For example from panel to T-Con if severe issue.
            Perhaps also from T-Con to mainboard.
            Guess this is not particularly helpful though.

            Comment

            • snme
              Member
              • Feb 2016
              • 26
              • AU

              #7
              Re: LG OLED55B7V doesn't turn on Help.

              Did you venture to find a manual that might offer T-Con and panel capability testing?
              On a recent job of mine, there was a means to jump start the T-Con in a test pattern, displaying variously RGBW across the panel.

              Comment

              • markolino
                Senior Member
                • Mar 2020
                • 108
                • Slovenia

                #8
                Re: LG OLED55B7V doesn't turn on Help.

                wow, that would be great, I can't imagine how it's done :-(

                Comment

                • snme
                  Member
                  • Feb 2016
                  • 26
                  • AU

                  #9
                  Re: LG OLED55B7V doesn't turn on Help.

                  Only by carefully following instructions in the manual, if it exists in the wild.
                  Still you have mentioned 5 sec life only, which is not encourgaging.
                  Last edited by snme; 09-12-2023, 07:13 AM. Reason: 5 sec

                  Comment

                  • markolino
                    Senior Member
                    • Mar 2020
                    • 108
                    • Slovenia

                    #10
                    Re: LG OLED55B7V doesn't turn on Help.

                    It lasts for 5 seconds only if the tcon is connected to the main board.. if I disconnect the 1 lower lvds cable that goes to the main board, then the TV turns on.

                    Comment

                    • Diah
                      Badcaps Legend
                      • Feb 2013
                      • 6336
                      • Germany

                      #11
                      Re: LG OLED55B7V doesn't turn on Help.

                      put back the LVDS you disconnected early from T-CON and Main boards

                      disconnect only the 20-24V socket of the cable between power boards and T-CON ( from Power boards side ) then turn on... check the audio output port if it lit red... yes.... keep it on for awhile as its ON plug back the socket back and give attention on the screen

                      Comment

                      • markolino
                        Senior Member
                        • Mar 2020
                        • 108
                        • Slovenia

                        #12
                        Re: LG OLED55B7V doesn't turn on Help.

                        I did exactly that. Turned on tv, optical port lit red, with tcon disconnected from power board and plugged it in after a couple minutes and the tv just powers off (standby) with optical red light off and nothing on screen. Tried 5 times already.

                        Comment

                        • Diah
                          Badcaps Legend
                          • Feb 2013
                          • 6336
                          • Germany

                          #13
                          Re: LG OLED55B7V doesn't turn on Help.

                          i wrote to give attention to the screen while you reconnect the socket.. to see what behavior the Panel do

                          A- No image at all or any line replace T-CON... its just small investment

                          B- image display with some lines or green spot .... scrap it

                          Comment

                          • markolino
                            Senior Member
                            • Mar 2020
                            • 108
                            • Slovenia

                            #14
                            Re: LG OLED55B7V doesn't turn on Help.

                            i was watching the screen.. through the mirror i had set up for myself.
                            nothing happens, not even a hundredth of a second, no lines appear, nothing.
                            it just sparks on the 28 pin connector when I plug it in and within 2 seconds it goes back to standby

                            Comment

                            • Diah
                              Badcaps Legend
                              • Feb 2013
                              • 6336
                              • Germany

                              #15
                              Re: LG OLED55B7V doesn't turn on Help.

                              yours t-con firm ware didn't start at all... keep the socket disconnect and send In_stop command with service RC or any app.... to let the firmware roil back on MB and t-con

                              you need to do it in blind time send command and then the code a sign of this action tv goes to STB state

                              Comment

                              • markolino
                                Senior Member
                                • Mar 2020
                                • 108
                                • Slovenia

                                #16
                                Re: LG OLED55B7V doesn't turn on Help.

                                I apologize. in this last step that you wrote me, I don't understand the process of how and when I have to press in_stop.
                                the 24v connector must be on or not??
                                and what code are you talking about??? I have an LG service remote.

                                Comment

                                • Diah
                                  Badcaps Legend
                                  • Feb 2013
                                  • 6336
                                  • Germany

                                  #17
                                  Re: LG OLED55B7V doesn't turn on Help.

                                  24V line should be disconnected ... so only the TV can start
                                  leave it on for awhile then send IN_STOP one second later press 0413 if the TV go to standby mean it received the command correct
                                  wait awhile and turn on .. 5 minute later as you keep it on plug back the 24V line yours eyes on the screen

                                  Comment

                                  • markolino
                                    Senior Member
                                    • Mar 2020
                                    • 108
                                    • Slovenia

                                    #18
                                    Re: LG OLED55B7V doesn't turn on Help.

                                    tried as you wrote. but it doesn't work. nothing. it still sparks on the 24v connector but the screen remains black...

                                    Comment

                                    • Diah
                                      Badcaps Legend
                                      • Feb 2013
                                      • 6336
                                      • Germany

                                      #19
                                      Re: LG OLED55B7V doesn't turn on Help.

                                      keep 24V line disconnected , and turn on.... measure if you have 12V on the T-CON fuse F1 from both side with Ref to chassis

                                      if you have 12V. try replace the t-CON
                                      Last edited by Diah; 09-13-2023, 07:57 AM.

                                      Comment

                                      • markolino
                                        Senior Member
                                        • Mar 2020
                                        • 108
                                        • Slovenia

                                        #20
                                        Re: LG OLED55B7V doesn't turn on Help.

                                        Anf wheree is Fuse F1 i dont find...
                                        Look picture

                                        In F5 have 24V
                                        In F3 have 12V
                                        Attached Files
                                        Last edited by markolino; 09-15-2023, 05:04 AM.

                                        Comment

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