Magnavox HDMI Loses sync on cable box,not computer

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  • frafreg
    Member
    • Apr 2017
    • 11
    • US
    #1

    Magnavox HDMI Loses sync on cable box,not computer

    I have a Magnavox model 19MF338B/F7 LCD TV. It works fine on all inputs except HDMI and component. If I plug my computer into the HDMI input, it works fine. If I connect a cable box HDMI output or any other TV converter HDMI output, it loses sync and I get a loud high pitched screeching sound.

    I have tested the RF and composite inputs which work fine. I'm guessing the main board may have a problem. I am willing to fix it if possible. Any help would be much appreciated. Thanks in advance.
    Frank
    Tags: None
    • budm
      Badcaps Legend
      • Feb 2010
      • 40746
      • USA
      #2
      Re: Magnavox HDMI Loses sync on cable box,not computer

      Did it work OK before? What is the history?
      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

        • frafreg
          Member
          • Apr 2017
          • 11
          • US
          #3
          Re: Magnavox HDMI Loses sync on cable box,not computer

          The HDMI input was never used before so I have no history. Strange that it works fine with a computer and not with a cable box. I tried a new HDMI cable and a new box with the same results. Once it starts to squeal and go out of sync, you can't even turn the set off from the remote or the switch. You have to pull the plug.

            Comment

            • frafreg
              Member
              • Apr 2017
              • 11
              • US
              #4
              Re: Magnavox HDMI Loses sync on cable box,not computer

              I found a bad 330 uf /16 volt cap on the main board. Replaced it with a 330 uf / 25 volt capacitor and the set is working fine now on the HDMI input from the cable box. The bad cap was located near the top of the large metal shield on the main board. The problem also fixed an issue with the component input which may be internally connected to the HDMI circuitry on the main board but I'm not sure since I don't have a schematic. Hope this information helps someone else with the same set, Magnavox model 19MF338B/F7. Thank you. Frank.

                Comment

                • budm
                  Badcaps Legend
                  • Feb 2010
                  • 40746
                  • USA
                  #5
                  Re: Magnavox HDMI Loses sync on cable box,not computer

                  Great work! You should upload the pictures and also provide the cap designator, I.E. C1.
                  So what is bad on the cap? High ESR/ Low capacitance?
                  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

                    • frafreg
                      Member
                      • Apr 2017
                      • 11
                      • US
                      #6
                      Re: Magnavox HDMI Loses sync on cable box,not computer

                      Hi Budm. I have pictures of the main board and the power supply but I don't have the cap designator information, sorry. The cap was swollen and leaking. It was easy to spot. The company name is CapXon and it is black with yellow writing.
                      I would like to upload the pictures but I don't see a button to upload. I can put an arrow on the main board picture showing the cap location. Will that be ok? Thanks. Frank

                        Comment

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