Sharp LC-37x20e power on but only for few seconds

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  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #21
    Re: Sharp LC-37x20e power on but only for few seconds

    Can we see good closed up pictures of the top and the bottom side of the board around the area where you replaced the IC7601?
    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

    Comment

    • clamel
      Member
      • Jul 2017
      • 20
      • Italy

      #22
      Re: Sharp LC-37x20e power on but only for few seconds

      Hello,
      IC7601 was copy and paste error.. I had to replace IC7904.. summarizing:

      IC7904 (9NK2510293234) TNY264PN --> It was very HOT. Replaced because it burnt after freezing. But during freezing it, the TV power came to life for some seconds, before this component burnt definitively.

      R7920 replaced because damaged after IC7904 burnt

      R7918 replaced but it was good

      IC7906 PC123Y82FZ0F --> Replaced, but after desoldering repeating tests on the old it had no problem.



      In attach some photo centered on IC7904, but also other replacements are visible.

      thank you very much for your patience
      Attached Files
      Last edited by clamel; 07-28-2017, 12:45 AM.

      Comment

      • budm
        Badcaps Legend
        • Feb 2010
        • 40746
        • USA

        #23
        Re: Sharp LC-37x20e power on but only for few seconds

        Is the snubber diode D7906 tested OK?
        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

        Comment

        • clamel
          Member
          • Jul 2017
          • 20
          • Italy

          #24
          Re: Sharp LC-37x20e power on but only for few seconds

          Originally posted by budm
          Is the snubber diode D7906 tested OK?
          yes, It seems to working fine.. with multimeter in diode mode, I read 0.479 V in one way, and OL in the other way. The readings are done with component soldered on the board.
          Last edited by clamel; 07-28-2017, 10:35 AM.

          Comment

          • clamel
            Member
            • Jul 2017
            • 20
            • Italy

            #25
            Re: Sharp LC-37x20e power on but only for few seconds

            Hello,
            I made some voltage measurement with power board connectet to AC.

            IC7904 - TNY264PN (using PIN2 as GND)
            pin1 - BP 5.85V
            pin2 - S 0V
            pin3 - S 0V
            pin4 - EN/UV 12.8 mV
            pin5 - D 309V
            pin7 - S (HV) 0V
            pin8 - S (HV) 0V

            I also measured voltage at some near components

            D7906 13V
            D7905 7.4V
            C7907 5.85V
            D7910 4.22V

            Is IC7904 working properly looking these voltages? What can I check in next steps?

            thanks

            BR

            Comment

            • clamel
              Member
              • Jul 2017
              • 20
              • Italy

              #26
              Re: Sharp LC-37x20e power on but only for few seconds

              Maybe ic7904 I replaced is bad? I don't undestand why I get only 1v instead of 5v

              Comment

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