Vizio E550VL Black Screen/PSU

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  • msrods
    Member
    • Apr 2015
    • 16
    • USA

    #1

    Vizio E550VL Black Screen/PSU

    I have replaced the T-Con and mainboard and nothing but when I look at the PSU resistors R304,305 and 308 only read 28 Ohm. They are marked 68 Ohm. Back of the PSU at resistors location is yellow compared to the rest of board. Is it possible why all I am getting at the 24VDC pins for the master and slave only 8 VDC. I am a novice so any help would be greatly appreciated.
  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #2
    Re: Vizio E550VL Black Screen/PSU

    Start by uploading good clear and well focused pictures of the whole back side of the TV so we can see how all the boards are connected together, then pictures of the TOP and BOTTOM sides of the power supply board.
    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

    • Alastair E
      Chief Womble
      • Mar 2013
      • 1963
      • U.K.

      #3
      Re: Vizio E550VL Black Screen/PSU

      Does voltage rise when BL boards disconnected...?
      TELEFIX

      How PLASMA SCREENS WORK, X-SUS and Y-SUS what they do--
      http://www.irf.com/technical-info/appnotes/an-1088.pdf
      PLEASE DO NOT EMAIL ME PRIVATELY FOR REPAIR ADVICE. QUESTIONS BELONG ON THE FORUM!

      Comment

      • msrods
        Member
        • Apr 2015
        • 16
        • USA

        #4
        Re: Vizio E550VL Black Screen/PSU

        No it does not. It falls off slowly to 4 VDC and holds there. BTW If someone can tell me how to post the pictures I will.

        Comment

        • msrods
          Member
          • Apr 2015
          • 16
          • USA

          #5
          Re: Vizio E550VL Black Screen/PSU

          Originally posted by budm
          Start by uploading good clear and well focused pictures of the whole back side of the TV so we can see how all the boards are connected together, then pictures of the TOP and BOTTOM sides of the power supply board.
          As per request here are the pictures.
          Attached Files

          Comment

          • budm
            Badcaps Legend
            • Feb 2010
            • 40746
            • USA

            #6
            Re: Vizio E550VL Black Screen/PSU

            "I look at the PSU resistors R304,305 and 308 only read 28 Ohm." They are connected in parallel so the total resistance is about 23 Ohms.
            So BOTH inverter boards are disconnected you still do not get 24VDC, right?
            Please check the DCV between the two legs of main filter cap C801A when TV is on to see if the Voltage is >360VDC.
            Pictures provided by SJ.
            Attached Files
            Last edited by budm; 04-03-2015, 09:01 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

            • msrods
              Member
              • Apr 2015
              • 16
              • USA

              #7
              Re: Vizio E550VL Black Screen/PSU

              Voltage is 168 DVC

              Comment

              • budm
                Badcaps Legend
                • Feb 2010
                • 40746
                • USA

                #8
                Re: Vizio E550VL Black Screen/PSU

                Originally posted by msrods
                Voltage is 168 DVC
                It should be more than 360Vdc when power switch isactivated and PS-ON is present, so that section needs to fixed or find out what is causing not to work.
                So just to be sure, the Voltage on the cap DID NOT JUMP up to >360VDC and then drops down, right?
                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

                • msrods
                  Member
                  • Apr 2015
                  • 16
                  • USA

                  #9
                  Re: Vizio E550VL Black Screen/PSU

                  It goes to 397 then drops back to 169.

                  Comment

                  • budm
                    Badcaps Legend
                    • Feb 2010
                    • 40746
                    • USA

                    #10
                    Re: Vizio E550VL Black Screen/PSU

                    OK, so the PFC Voltage did come on and then drops out, then you need to find out if the PS-ON signal also drops out or not next.
                    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

                    • msrods
                      Member
                      • Apr 2015
                      • 16
                      • USA

                      #11
                      Re: Vizio E550VL Black Screen/PSU

                      How do I check that?

                      Comment

                      • budm
                        Badcaps Legend
                        • Feb 2010
                        • 40746
                        • USA

                        #12
                        Re: Vizio E550VL Black Screen/PSU

                        The white connector on the power supply board that goes to the main board has the pin labeled with name of the pin next to it, so list each pin name and the measured DC Voltage reading (when TV power switch is activated) next to each one.
                        See CN201:
                        http://assets.shopjimmy.com/media/ca...0790-top_1.jpg
                        Last edited by budm; 04-04-2015, 08:28 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

                        • msrods
                          Member
                          • Apr 2015
                          • 16
                          • USA

                          #13
                          Re: Vizio E550VL Black Screen/PSU

                          PS is 2.88 The next 3 which should be 12VDC are 13VDC and the bottom 3 which should be 5VDC are 5.04VDC

                          Comment

                          • budm
                            Badcaps Legend
                            • Feb 2010
                            • 40746
                            • USA

                            #14
                            Re: Vizio E550VL Black Screen/PSU

                            OK, something does not make sense here, you are saying that you do have 12VDC (13VDC) on the coNnector CN201, but you are getting only 8V on the 24VDC on CN202, CN203. The problem is that the 12V and the 24V are generated by the same circuit, so to have only 8V on the 24V but the 12V is OK does not make sense, I would expect the 12V will be very low also. If both inverter boards are not connected, the Voltage should be a lot higher than 8V.
                            Something else is also causing the PFC Voltage circuit to drop out also.
                            You are having the same problem as this one:
                            https://www.badcaps.net/forum/showth...-321%2A&page=2
                            But the OP never comes back to tell us what happen after I wasted so much times tracing out the connections.
                            Attached Files
                            Last edited by budm; 04-04-2015, 11:09 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

                            • msrods
                              Member
                              • Apr 2015
                              • 16
                              • USA

                              #15
                              Re: Vizio E550VL Black Screen/PSU

                              First off I will stay with this until the problem is solved. I will pull the board and turn it over and check the voltages as indicated on the traced picture. I have been checking all the voltages one the front side at the pins. Maybe I am missing something. Have a Happy Easter.

                              Comment

                              • msrods
                                Member
                                • Apr 2015
                                • 16
                                • USA

                                #16
                                Re: Vizio E550VL Black Screen/PSU

                                Don't know if this maters or not, but depending on where I put the ground clip the voltages vary by 4VDC and if I use the sig gnd for the grounds I get no voltage same with the GP1 on the board.

                                Comment

                                • budm
                                  Badcaps Legend
                                  • Feb 2010
                                  • 40746
                                  • USA

                                  #17
                                  Re: Vizio E550VL Black Screen/PSU

                                  Right now we are interested in the 24V power supply section without having the inverter boards connected to CN203, CN202. You just put the meter probe on CN203 PIN 1 (24vdc) and black probe on pin 7 to see what DCV you get.
                                  The boards will be mounted in place.
                                  And in what section are you checking the Voltage, the primary side circuit? the secondary side circuit?
                                  We also still need to find out why the PFC Voltage drops down.
                                  Last edited by budm; 04-05-2015, 05:59 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

                                  • msrods
                                    Member
                                    • Apr 2015
                                    • 16
                                    • USA

                                    #18
                                    Re: Vizio E550VL Black Screen/PSU

                                    Using pin 1 and pin 7 (black probe) I get no voltage at all. Testing on the secondary voltage side. If I use H55 on secondary side for ground point I get 0 VDC, if I use H53 on primary side for ground I get 20.11VDC.

                                    Comment

                                    • msrods
                                      Member
                                      • Apr 2015
                                      • 16
                                      • USA

                                      #19
                                      Re: Vizio E550VL Black Screen/PSU

                                      My post should have said HS3 and HS5 instead of H53 and H55

                                      Comment

                                      • budm
                                        Badcaps Legend
                                        • Feb 2010
                                        • 40746
                                        • USA

                                        #20
                                        Re: Vizio E550VL Black Screen/PSU

                                        Originally posted by msrods
                                        Using pin 1 and pin 7 (black probe) I get no voltage at all. Testing on the secondary voltage side. If I use H55 on secondary side for ground point I get 0 VDC, if I use H53 on primary side for ground I get 20.11VDC.
                                        Primary circuit Ground point cannot be used for the Gnd ref for the seocndary side, and secondary side GND ref cannot be used for the primary Gnd ref.
                                        So pin 1 and pin 7 of the 24VDC output connector is showing 0V but you do have 12V and the 18V?
                                        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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