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Vizio VO42L question

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    #41
    Re: Vizio VO42L question

    What kind of voltages should I expect at the FET transistors or transformer inputs?
    On the secondary transformer inputs, all the inputs are 5.8V, and on the master all the inputs are 0.228V.

    Comment


      #42
      Re: Vizio VO42L question

      There will be 24V at the Drain of two MOSFET's top half of the bridge setup, the drive is a full bridge setup, since all the MOSFET's are off when they are not driven by the IC, the Source/Drain center connection will be 0 volt, the transfomer has DC blocking caps which means you will not see any DC voltage reading on the primary winding, see the SCH I provided earlier.
      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


        #43
        Re: Vizio VO42L question

        I'm not that good to be able to diagnose this any further.
        I have re-checked both boards, I have notices some solder ball under the slave chip and by trying to remove it from behind the chip's pins I have noticed that one of the pins wasn't soldered properly.
        So went through both chips again and after re-soldering each pin, I have got a change on the master board.
        I have almost the same voltages as the slave FETs, but still a no go.
        MQ1
        G- 5.6V
        D- 25.05V
        S- 5.6V

        MQ4
        G- 5.5V
        D- 25.05V
        S- 5.5V

        MQ2
        G- 0V
        D- 5.6V
        S- 0V

        MQ5
        G- 0V
        D- 5.5V
        S- 0V
        Last edited by tibimakai; 08-01-2012, 12:18 AM.

        Comment


          #44
          Re: Vizio VO42L question

          Any other input would be appreciated.

          Comment


            #45
            Re: Vizio VO42L question

            There is only one fuse on these boards or there is another one?
            I see in repair kits they sell a 0.1ohm fusible resistor also with the IC and FET transistors.
            I also see some new replacement boards from China, anybody has any experience with these? Both for $36!!
            http://www.ebay.com/itm/Brand-New-Re...item4d03e71e27
            or from an US seller for $38
            http://www.ebay.com/itm/New-Inverter...item27ca031509
            Last edited by tibimakai; 08-27-2012, 08:10 PM.

            Comment


              #46
              Re: Vizio VO42L question

              I saw those kit with the 0.1 Ohm resistors in the kit, it does not say where they used at, i am sure they want you to buy the kit to find out where they go.
              $38 for both is cheap!
              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


                #47
                Re: Vizio VO42L question

                Cheap and hopefully the problem it's gone. I will look one more time at this TV and if I can't see anything wrong then I will buy these boards.

                Comment


                  #48
                  Re: Vizio VO42L question

                  OK, I have got those new style boards in and the TV it's alive!!!
                  The only issue I have is that I can't install the metal shield on them.

                  Comment


                    #49
                    Re: Vizio VO42L question

                    Glad to hear that they fixed the problem. I left my metal shields off, it will run cooler, and since they are inside the TV, the customer cannot get to them unless they open it up.
                    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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