Magnavox 42mf437b/37 picture fades

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  • mckkcm001
    New Member
    • Feb 2015
    • 4
    • USA
    #1

    Magnavox 42mf437b/37 picture fades

    Hello,

    I recently purchased a used Magnavox 42mf437b/37 to display student work in the hallway. The only hitch was that it had to be turned on/off several times before the picture would stay on.

    Now the picture fades almost immediately no matter how many times the power is cycled.

    I replaced the capacitors and two diodes on the power board. After a couple of on/off cycles, the picture remained. Then after about half an hour, I moved the TV, and I'm back to having the picture fade almost immediately.

    I can access the 123654 menu from the remote and the other smaller menus, but the main menu fades quickly so I can't access the factory reset mode.

    Also, there is a speaker wire attached to the power switch assembly that connects to nothing. One wire is soldered in and the other is under an attachment screw.

    From the back of the TV, even though the picture has faded, there is a bright white light showing through a couple of openings in the back panel.

    Any help would be appreciated.
    Tags: None
    • CapLeaker
      Leaking Member
      • Dec 2014
      • 8327
      • Canada
      #2
      Re: Magnavox 42mf437b/37 picture fades

      O.k. so you got back light. Try to twist and or squeeze the frame a little on top, bottom and the sides. Sounds like tab bond problem. Can we see hi res pictures of the screen and all the boards?

        Comment

        • mckkcm001
          New Member
          • Feb 2015
          • 4
          • USA
          #3
          Re: Magnavox 42mf437b/37 picture fades

          Thanks for your reply.

          I can access the 123654 information using the remote.

          The other two pictures show the menu screen fading out after hitting menu on the remote.

          What is a tab? I squeezed the frame and it seemed to make the picture last a bit longer.
          Attached Files

            Comment

            • tom66
              EVs Rule
              • Apr 2011
              • 32560
              • UK
              #4
              Re: Magnavox 42mf437b/37 picture fades

              I have seen this before, it is due to a tab bonding failure (panel failure) it MAY be fixable, but I've had bad luck doing it. Videos available on youtube demonstrate the fix, adding shims to the tab bonds to apply appropriate pressure to the tab bonds.
              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

                • mckkcm001
                  New Member
                  • Feb 2015
                  • 4
                  • USA
                  #5
                  Re: Magnavox 42mf437b/37 picture fades

                  I took the TV apart again and noticed a bulging capacitor on the board to the right of the power supply so I will try replacing that.

                  I will also check out the tab adjustment.

                  Thanks.

                    Comment

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