LG 42PX3RVA no picture

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  • caspermccormack
    Senior Member
    • Mar 2012
    • 112
    • Ireland

    #1

    LG 42PX3RVA no picture

    Hello, I have a fault in the above tv, when i stripped it down i seen that the y-sus had a blown fuse which led me to believe that the module was also shot too. I have replaced the module and the fuse but still no picture, I have measured the AC detect and it is 4.41 stand by and 4.42 while on. All other voltages are correct coming from the PSU.

    Any Ideas????

    here is a pic of the damage on the module
    Click image for larger version

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  • caspermccormack
    Senior Member
    • Mar 2012
    • 112
    • Ireland

    #2
    Re: LG 42PX3RVA no picture

    Tv has sound but no picture.

    Comment

    • tom66
      EVs Rule
      • Apr 2011
      • 32560
      • UK

      #3
      Re: LG 42PX3RVA no picture

      AC detect is OK, because you have sound PSU is OK, problem is likely other fault on Y-sus, check for 200V Vs.
      Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
      For service manual, schematic, boardview (board view), datasheet, cad - use our search.

      Comment

      • caspermccormack
        Senior Member
        • Mar 2012
        • 112
        • Ireland

        #4
        Re: LG 42PX3RVA no picture

        Originally posted by tom66
        AC detect is OK, because you have sound PSU is OK, problem is likely other fault on Y-sus, check for 200V Vs.
        Thanks Tom,

        187.7 on Vs , sticker says 187v,

        Comment

        • tom66
          EVs Rule
          • Apr 2011
          • 32560
          • UK

          #5
          Re: LG 42PX3RVA no picture

          OK, check for shorts on Y-sustain. From either end of fuse to ground / chassis.
          Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
          For service manual, schematic, boardview (board view), datasheet, cad - use our search.

          Comment

          • caspermccormack
            Senior Member
            • Mar 2012
            • 112
            • Ireland

            #6
            Re: LG 42PX3RVA no picture

            [QUOTE=tom66;277158]OK, check for shorts on Y-sustain. From either end of fuse to ground / chassis.


            Checked that, no shorts.

            Comment

            • tom66
              EVs Rule
              • Apr 2011
              • 32560
              • UK

              #7
              Re: LG 42PX3RVA no picture

              Any glow from screen in dark room?
              Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
              For service manual, schematic, boardview (board view), datasheet, cad - use our search.

              Comment

              • caspermccormack
                Senior Member
                • Mar 2012
                • 112
                • Ireland

                #8
                Re: LG 42PX3RVA no picture

                No tom, nothing at all.

                Comment

                • tom66
                  EVs Rule
                  • Apr 2011
                  • 32560
                  • UK

                  #9
                  Re: LG 42PX3RVA no picture

                  I cannot be sure if it is the control board or the Y-sustain. You would need a scope to verify if the control board is functioning.
                  Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                  For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                  Comment

                  • caspermccormack
                    Senior Member
                    • Mar 2012
                    • 112
                    • Ireland

                    #10
                    Re: LG 42PX3RVA no picture

                    Originally posted by tom66
                    I cannot be sure if it is the control board or the Y-sustain. You would need a scope to verify if the control board is functioning.
                    Got another tv today to look over and it's the same model as this one I have. I changed over the Y-Sus boards and my one is now working again. So know I know it is the Y-Sus. I have checked over for shorts on the module and found none. So what else can I look for to the board? It doesn't shut off the tv, and the sound is present.


                    Now, with the good Y-Sus installed back into the TV that I got today, I have a bad picture, lots of ghosting and speckels on the whole screen, What would be the solution to rectify this kind of fault??

                    Cheers boys!

                    Comment

                    • tom66
                      EVs Rule
                      • Apr 2011
                      • 32560
                      • UK

                      #11
                      Re: LG 42PX3RVA no picture

                      See
                      https://www.badcaps.net/forum/showpo...29&postcount=7

                      In particular, adjustment of potentiometers.

                      However, problem is likely TV is in need of new control board or software flashing.
                      Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                      For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                      Comment

                      • caspermccormack
                        Senior Member
                        • Mar 2012
                        • 112
                        • Ireland

                        #12
                        Re: LG 42PX3RVA no picture

                        Originally posted by tom66
                        See
                        https://www.badcaps.net/forum/showpo...29&postcount=7

                        In particular, adjustment of potentiometers.

                        However, problem is likely TV is in need of new control board or software flashing.
                        Sound Tom, nice one for your input!

                        I'll try that tomorrow. I may check over the faulty Y-Sus board for those voltages to make sure they are there. Is there any other component on the y-sus that I may be able to test and get it back working?

                        Comment

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