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    Need schematic for Visio LC420

    Before I come to request assistance, I would like to do my own due diligence fin troubleshooting this dead set. If someone has a schematic of the power board or the entire set I would greatly appreciate so very much. I love this forum and site it's the only one I follow for years.

    Thanks so very much in advance!,

    #2
    Re: Need schematic for Visio LC420

    2: that does not look like Vizio TV model number. That sounds more like the LCD panel model number.
    2: if you upload good clear straight shot high-res pictures of the whole Top and Bottom side of the board then you may get more help.
    3: I doubt that we will find the schematic of the power supply board, it is made by the third party.
    What Voltages did you test on the power supply board so far?
    The more details you provide the more help you will get.
    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


      #3
      Re: Need schematic for Visio LC420

      Thanks Bubm, I remember your excellent troubleshooting guide. Thanks for referencing it again for me and let me get some measurements and pictures read for reply.

      Thanks!

      Comment


        #4
        Re: Need schematic for Visio LC420

        So what is the correct TV model?
        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


          #5
          Re: Need schematic for Visio LC420

          It’s an LED E series E420 VL
          Have 5v SB, 12vdc. No 24vdc. No switched PSon 5v.

          Going to take photos and post. Fron Visio light is amber and not changing to white, confirming no PSON 5v. So no PSON SIGNAL FROM system. Have not connected a load to PS check 12vdc but do not believe I have a 24v rail to test. Would love a schematic to do further troubleshooting but happy to have your valuable input and assistance.

          I have reviewed the excellent document you authored as a basis for proving the above.

          Comment


            #6
            Re: Need schematic for Visio LC420

            I believe the E420VL uses ccfl backlighting and not LED. You might want to provide some good photos of the boards and how they're all connected.

            Comment


              #7
              Re: Need schematic for Visio LC420

              [PHP[/PHP]



              Please advise if these photos contain sufficient detail for assistance.

              Thanks
              Attached Files

              Comment


                #8
                Re: Need schematic for Visio LC420

                Originally posted by jetadm123 View Post
                I believe the E420VL uses ccfl backlighting and not LED. You might want to provide some good photos of the boards and how they're all connected.
                Just uploaded please advise regarding detail.

                Thanks

                Comment


                  #9
                  Re: Need schematic for Visio LC420

                  http://www.shopjimmy.com/vizio-0500-...upply-unit.htm pic. of powersupply board if that's it.
                  Last edited by nomoresonys; 03-24-2018, 02:24 PM.

                  Comment


                    #10
                    Re: Need schematic for Visio LC420

                    I was wondering with no PSON SIGNAL, audio or BL, would removing the ribbon connections from the TCon/system board to the BL lamps allow some isolation of the trouble to determine if PSON and audio could then be rechecked.

                    None of the SM FUSES are blown and there are no suspicious visual capacitor concerns to indication gassing or leakage.

                    Comment


                      #11
                      Re: Need schematic for Visio LC420

                      You have power supply/inverter board combo for CCFL backlights.
                      The connector on the power supply that goes to the main board has lable for each pin, can you please provide the DC V readings for each one of those pin.
                      You also have to fuses on the main board close to the connector that goes back to the power supply board, please check the DC V at both ends of the fuse with ref. to the chassis GND, one should show 5V and another one is for switched 12V.
                      You also have some LDO Voltage regulator IC's on the main board that you should check.
                      Did you look at shopjimmy to see if they have EEPROM for this model?
                      Last edited by budm; 03-24-2018, 02:32 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


                        #12
                        Re: Need schematic for Visio LC420

                        Originally posted by nomoresonys View Post
                        http://www.shopjimmy.com/vizio-0500-...upply-unit.htm pic. of powersupply board if that's it.
                        Thanks for the link to SJ regarding the parts. I haven't been able to determine why I am not seeing any PSON signal to the power supply. Since I believe this signal comes from the system/TCON board, this could be the source of the failure. Is there any way to momentarily connect the 5vSB to the PSON lead to see if the set will start without damage to the system board?

                        Comment


                          #13
                          Re: Need schematic for Visio LC420

                          To force on the power supply, you MUST disconnect the wires (I.E. PS-ON, BL-ON) going back to the main board first otherwise you will damage the main 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


                            #14
                            Re: Need schematic for Visio LC420

                            https://www.youtube.com/watch?v=mUvclBfaMXg
                            Powersupply testing, you don't have to remove the board from the tv tho, just disconnect all the other boards.
                            Last edited by nomoresonys; 03-24-2018, 03:13 PM.

                            Comment


                              #15
                              Re: Need schematic for Visio LC420

                              Originally posted by budm View Post
                              You have power supply/inverter board combo for CCFL backlights.
                              The connector on the power supply that goes to the main board has lable for each pin, can you please provide the DC V readings for each one of those pin.
                              You also have to fuses on the main board close to the connector that goes back to the power supply board, please check the DC V at both ends of the fuse with ref. to the chassis GND, one should show 5V and another one is for switched 12V.
                              You also have some LDO Voltage regulator IC's on the main board that you should check.
                              Did you look at shopjimmy to see if they have EEPROM for this model?
                              Burn,

                              Per the above attaching picture of power board connector to system board.

                              Pin 1 3vdc
                              Pin 4 1.6vdc
                              Pins5-7 12.2vdc
                              Pins 8-11 0vdc
                              Pins 12-15 5.2vdc

                              160μf cap on power board 325vdc
                              All fuses on system and power board good.
                              Removed HDMI chip since customer reported no working HDMI ports before set set died, thinking possibility the IC MIGHT BE SHORTED.

                              Please let me know if I have provided you sufficient information to continue your assistance

                              Comment


                                #16
                                Re: Need schematic for Visio LC420

                                Originally posted by budm View Post
                                You have power supply/inverter board combo for CCFL backlights.
                                The connector on the power supply that goes to the main board has lable for each pin, can you please provide the DC V readings for each one of those pin.
                                You also have to fuses on the main board close to the connector that goes back to the power supply board, please check the DC V at both ends of the fuse with ref. to the chassis GND, one should show 5V and another one is for switched 12V.
                                You also have some LDO Voltage regulator IC's on the main board that you should check.
                                Did you look at shopjimmy to see if they have EEPROM for this model?
                                Did you see the pictures I just attached as requested?

                                Comment


                                  #17
                                  Re: Need schematic for Visio LC420

                                  Originally posted by jkb242 View Post
                                  Thanks for the link to SJ regarding the parts. I haven't been able to determine why I am not seeing any PSON signal to the power supply. Since I believe this signal comes from the system/TCON board, this could be the source of the failure. Is there any way to momentarily connect the 5vSB to the PSON lead to see if the set will start without damage to the system board?
                                  It's that BUT more over it's a good close up pic. of the board, these are what you need to post, front and back.

                                  Comment


                                    #18
                                    Re: Need schematic for Visio LC420

                                    One of the pictures I attempted to post shows the power board to system board connection and labeling of the connector. However since none of these will post for some reason. Beginning with Pin one, the pins are labeled:
                                    5.1VSB PIN1-3 measured 5.2vd
                                    SGND PINS 4-7 measured 0vdc
                                    12V PINS 8-11 measured 12vdc
                                    PSON PIN 12 measured 1.17 vdc
                                    I-ON/OFF PIN 13 measured 0vdc
                                    LAMP PIN 14 measured 0vdc
                                    DIM PIN 15 measured 0vdc

                                    PLEASE DISREGARD THE EARLIER VOLTAGE READINGS POSTED, very sorry for being so sloppy in my reporting. I am still trying to figure out why no none of the pictures are being posted. Thanks so very much. My system board is not available at SJ.

                                    Comment


                                      #19
                                      Re: Need schematic for Visio LC420

                                      Now posting picture of power board connector to main board as a supplement to last post and previous from Budm.
                                      Attached Files

                                      Comment


                                        #20
                                        Re: Need schematic for Visio LC420

                                        Detailed views of power and system boards and inter connection. Please advise if additional informational information is required. Working without a schematic is more difficult for me as I am not that familiar with this set and really appreciate the assistance I am receiving!

                                        Thanks
                                        Attached Files

                                        Comment

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