RCA TV no picture, replaced all boards. Backlight ok

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  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA
    #21
    Re: RCA TV no picture, replaced all boards. Backlight ok

    "I checked the voltage at the main board with and without the LVDS cable connected. There was not 12v anywhere. (The highest was about 2.3v) The cable is not damaged or pinched."
    You have to have the switched 12VDC (It will be present when the power supply board receives the PS-ON from the main board) from the power supply board to feed the main board, then that 12V is fed through the switched Power MOSFET to supply the 12V to the T-CON when TV is powered on. The 12V is also used by the Audio circuit.
    You should also report the DCV reading of each pins of the connectors of the power supply to see what you have and what you do not have.
    Also post closed up pictures of this MEGMEET MLT-198TX power supply connector without the cable in place so we can see the labels of the connectors' pin.

    http://www.shopjimmy.com/megmeet-mlt...wer-supply.htm
    Last edited by budm; 03-13-2016, 10:02 PM.
    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

      • Bfritz97
        Member
        • Mar 2016
        • 16
        • United States
        #22
        Re: RCA TV no picture, replaced all boards. Backlight ok

        From top to bottom (bottom being where CON5 is printed):
        12.25
        12.25
        -0.02
        -0.02
        -0.02
        5.08
        5.08
        5.1
        4.23
        5.08
        5.08
        -0.03
        -0.03
        This is on the main power board at the main connector. It is the only connector that has voltages printed next to it
        Attached Files

          Comment

          • budm
            Badcaps Legend
            • Feb 2010
            • 40746
            • USA
            #23
            Re: RCA TV no picture, replaced all boards. Backlight ok

            You correct Voltages (Standby 5VSB, switched 5V, switched 12V, and STB (PS-ON) signal).
            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

              • Bfritz97
                Member
                • Mar 2016
                • 16
                • United States
                #24
                Re: RCA TV no picture, replaced all boards. Backlight ok

                So does this mean that the power supply is ok? And the main board is telling it to turn on, but could something else be wrong on the main board?

                  Comment

                  • Bfritz97
                    Member
                    • Mar 2016
                    • 16
                    • United States
                    #25
                    Re: RCA TV no picture, replaced all boards. Backlight ok

                    Hello?

                      Comment

                      • budm
                        Badcaps Legend
                        • Feb 2010
                        • 40746
                        • USA
                        #26
                        Re: RCA TV no picture, replaced all boards. Backlight ok

                        ""I checked the voltage at the main board with and without the LVDS cable connected. There was not 12v anywhere. (The highest was about 2.3v) The cable is not damaged or pinched." Since you do have 12V at the power supply, then you should have 12V at the connector of the main board. If you do have it at the connector then you have problem on the main board somewhere.
                        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

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