Sanyo DP42740 won't turn on, but has power

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  • Scuse
    Senior Member
    • Jan 2013
    • 50
    • United States

    #1

    Sanyo DP42740 won't turn on, but has power

    My Sanyo DP42740 Plasma won't turn on anymore. The power light nor the screen will even light up. not even an error code. I removed the back of the TV, and tested a few voltages and fuses and everything so far seems to be about right. I haven't been able to track down a service manual for this model though. I tried disconnecting different wires from the power board, and the only difference I was able to make was when I disconnect the SS board, on the right, from the power board the TV clicks on and the power led on the front of the TV will come on for a few seconds, then off for a few, then on again, etc. still no picture, audio, or even a dim light though. Could his mean the SS board is bad? I read in a few forums where others with similar symptoms had replaced the main board and all was cured. I bought a digital main and installed it, but no change. There's also a guy with a you tube video that said the same thing, with the same model TV, but his main board and mine are different. His is all one piece, but mine is half analog and half digital connected by a row of pins. Any help or comments would be great. Thanks!
    Attached Files
  • Scuse
    Senior Member
    • Jan 2013
    • 50
    • United States

    #2
    Re: Sanyo DP42740 won't turn on, but has power

    Close up of cord disconnected
    Attached Files

    Comment

    • Scuse
      Senior Member
      • Jan 2013
      • 50
      • United States

      #3
      Re: Sanyo DP42740 won't turn on, but has power

      Close up of digital board
      Attached Files

      Comment

      • cliff_hootarski
        Badcaps Veteran
        • Jul 2006
        • 411
        • USA

        #4
        Re: Sanyo DP42740 won't turn on, but has power

        I fixed one of these with similar problems. Xsus board had a short on it, so unplugging it, I got good voltages but still no picture (can't remember if the power supply cycled or not).
        Also found several shorted Mosfets and Diodes on the Ysus board. I found the boards cheap enough to warrant replacement, rather than component replacement.

        Comment

        • Scuse
          Senior Member
          • Jan 2013
          • 50
          • United States

          #5
          Re: Sanyo DP42740 won't turn on, but has power

          Do you think I should change just the one first, or both at the same time? Thanks

          Comment

          • tom66
            EVs Rule
            • Apr 2011
            • 32560
            • UK

            #6
            Re: Sanyo DP42740 won't turn on, but has power

            Due to how the power is chained between boards (combined energy recovery), I would recommend swapping both and checking the buffer board for shorts:
            http://www.youtube.com/watch?v=51SZsfH60EY
            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

            • cliff_hootarski
              Badcaps Veteran
              • Jul 2006
              • 411
              • USA

              #7
              Re: Sanyo DP42740 won't turn on, but has power

              The Ysus and buffers are all one board.

              Comment

              • tom66
                EVs Rule
                • Apr 2011
                • 32560
                • UK

                #8
                Re: Sanyo DP42740 won't turn on, but has power

                Ah OK then no need to test them.
                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

                • Scuse
                  Senior Member
                  • Jan 2013
                  • 50
                  • United States

                  #9
                  Re: Sanyo DP42740 won't turn on, but has power

                  Okay....soooo....I'm thinking ill just order the SS board first and see what happens. Feeling lucky

                  Comment

                  • tom66
                    EVs Rule
                    • Apr 2011
                    • 32560
                    • UK

                    #10
                    Re: Sanyo DP42740 won't turn on, but has power

                    Brave.
                    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

                    • cliff_hootarski
                      Badcaps Veteran
                      • Jul 2006
                      • 411
                      • USA

                      #11
                      Re: Sanyo DP42740 won't turn on, but has power

                      At the very least, check the SS board for shorts to ground. Also do a quick in circuit test on the heatsink components on the Ysus board (the big board on the left). mine had several shorted components!

                      Comment

                      • Scuse
                        Senior Member
                        • Jan 2013
                        • 50
                        • United States

                        #12
                        Re: Sanyo DP42740 won't turn on, but has power

                        Yeah, I may as well just get em both.

                        Comment

                        • johnboy1313
                          Badcaps Legend
                          • Nov 2012
                          • 1959
                          • USA

                          #13
                          Re: Sanyo DP42740 won't turn on, but has power

                          Scuse, did you get the set working? I have the same set with the same issue. I disconnected the SN and SS boards with no change. All voltages are present and accounted for on the PSU, no picture, sound or indicator LED though, only a click when the set is plugged in.

                          Comment

                          • johnboy1313
                            Badcaps Legend
                            • Nov 2012
                            • 1959
                            • USA

                            #14
                            Re: Sanyo DP42740 won't turn on, but has power

                            I guess I didn't read your original post close enough. Looks like I'm having different issues than you did.

                            Comment

                            • Ovalking
                              Senior Member
                              • Jul 2013
                              • 57
                              • Usa

                              #15
                              Re: Sanyo DP42740 won't turn on, but has power

                              Originally posted by johnboy1313
                              Scuse, did you get the set working? I have the same set with the same issue. I disconnected the SN and SS boards with no change. All voltages are present and accounted for on the PSU, no picture, sound or indicator LED though, only a click when the set is plugged in.
                              I have one doing same thing did you get yours fixed ?

                              Comment

                              • johnboy1313
                                Badcaps Legend
                                • Nov 2012
                                • 1959
                                • USA

                                #16
                                Re: Sanyo DP42740 won't turn on, but has power

                                Originally posted by Ovalking
                                I have one doing same thing did you get yours fixed ?
                                I was having a different problem.

                                https://www.badcaps.net/forum/showthread.php?t=28850

                                Comment

                                • Shane711
                                  Badcaps Veteran
                                  • Dec 2014
                                  • 493
                                  • USA

                                  #17
                                  Re: Sanyo DP42740 won't turn on, but has power

                                  I am working on a Sanyo DP42740. My problem seems to be the EEPROM. I have ordered parts to fix it.

                                  Comment

                                  • Shane711
                                    Badcaps Veteran
                                    • Dec 2014
                                    • 493
                                    • USA

                                    #18
                                    Re: Sanyo DP42740 won't turn on, but has power

                                    I received the New EEPROM today and installed it but my problem is not fixed. My next step is to test every capacitor on the power board.

                                    Comment

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