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37lg7000 sound. No picture but backlight on.

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    37lg7000 sound. No picture but backlight on.

    As above,
    Any help would be greatly appreciated with diagnosing the problem board.

    #2
    Re: 37lg7000 sound. No picture but backlight on.

    Pictures?

    Include a picture of the t-con.

    Check each end of the pico fuse on the t-con.
    You should have 12v on each end.

    Comment


      #3
      Re: 37lg7000 sound. No picture but backlight on.

      If you have an oscilloscope, measure the LVDS out of the main board, while flicking the menu on and off.

      Comment


        #4
        Re: 37lg7000 sound. No picture but backlight on.

        No scope. I think tcon ok. Blue light comes on when set powered up. Think its main board of screen not sure.

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          #5
          Re: 37lg7000 sound. No picture but backlight on.

          Blue light doesn't mean the t-con is working.

          Unplug half the tcon and see if you get an image on either side on the tv.

          We need a photo of the tcon to see test points.

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            #6
            Re: 37lg7000 sound. No picture but backlight on.

            chances are 50/50.

            Comment


              #7
              Re: 37lg7000 sound. No picture but backlight on.

              Originally posted by hamie View Post
              blue light doesn't mean the t-con is working.

              Unplug half the tcon and see if you get an image on either side on the tv.

              We need a photo of the tcon to see test points.
              +1.
              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

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                #8
                Re: 37lg7000 sound. No picture but backlight on.

                If I unplug half the tcon I get half a white screen on the side I unplug
                Attached Files

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                  #9
                  Re: 37lg7000 sound. No picture but backlight on.

                  Tcon
                  Attached Files

                  Comment


                    #10
                    Re: 37lg7000 sound. No picture but backlight on.

                    Check voltages on t-con.

                    Vdd
                    Vcom
                    Vgl
                    Vgh

                    Post results.

                    Comment


                      #11
                      Re: 37lg7000 sound. No picture but backlight on.

                      Sorry.. Where exactly do I take the reading from?

                      Comment


                        #12
                        Re: 37lg7000 sound. No picture but backlight on.

                        if you look at the tcon where the top white connectors are for the ribbon cables just under there on each side there are the test points marked with a gold test point, put the black multi meter probe on the tv metal chassis and try not to let the probe slip and short anything out.

                        Comment


                          #13
                          Re: 37lg7000 sound. No picture but backlight on.

                          Vgl 2.5v
                          Think vcom_r 6.3v or 17mv (there's 2 test points under the vcom r writing not sure which is right)
                          Vcom_l is 12.6v
                          Vgh 12mv
                          Vcc 3.3v
                          Vdd 16.9v

                          Comment


                            #14
                            Re: 37lg7000 sound. No picture but backlight on.

                            i think the readings are meant to be took above the white line just to top left if that makes sence

                            Comment


                              #15
                              Re: 37lg7000 sound. No picture but backlight on.

                              Vcom is here:



                              Can you check vgl and vgh again as they are definitely not right.


                              Vdd is ok.

                              Vgl should give a negative reading. Ie -6v
                              Vgh should be about 15v
                              Last edited by Hamie; 10-03-2015, 01:00 PM.

                              Comment


                                #16
                                Re: 37lg7000 sound. No picture but backlight on.

                                Vcom 6.9v

                                Comment


                                  #17
                                  Re: 37lg7000 sound. No picture but backlight on.

                                  Vcom is fine.

                                  Comment


                                    #18
                                    Re: 37lg7000 sound. No picture but backlight on.

                                    did you see my post 14 you may need to check the readings again

                                    Comment


                                      #19
                                      Re: 37lg7000 sound. No picture but backlight on.

                                      Taking readings from here. The dot under each one and readings are as previously stated
                                      Attached Files

                                      Comment


                                        #20
                                        Re: 37lg7000 sound. No picture but backlight on.

                                        possible i still think you need to check them above and too the left of the white line as if you count the numbers starting with a v theres just enough gold dots to match under the whie line but above there 4 test points whats hamie opinion?
                                        Last edited by vinceroger69; 10-03-2015, 01:18 PM.

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