Vizio VT420M No picture

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  • landyboy
    Badcaps Veteran
    • Apr 2013
    • 443
    • USA
    #21
    Re: Vizio VT420M No picture

    I found two regulators on the main board. Using the provided testing procedure. I believe the first one is testing good. The second one:
    U702
    903T63 L161
    Pin 1 0
    Pin 2 3.293v
    Pin 3 5.115v

    I am still attempting to find a data sheet for that one.

      Comment

      • tom66
        EVs Rule
        • Apr 2011
        • 32560
        • UK
        #22
        Re: Vizio VT420M No picture

        It would appear that regulator is OK. There is also at least one regulator on the T-con board.
        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

          • landyboy
            Badcaps Veteran
            • Apr 2013
            • 443
            • USA
            #23
            Re: Vizio VT420M No picture

            Ok using the provided procedure both of the regulators on the main board test good. I guess I will look for a Tcon board. Boards for this model seem expensive.

              Comment

              • landyboy
                Badcaps Veteran
                • Apr 2013
                • 443
                • USA
                #24
                Re: Vizio VT420M No picture

                Tcon ordered I will post results once installed..

                  Comment

                  • landyboy
                    Badcaps Veteran
                    • Apr 2013
                    • 443
                    • USA
                    #25
                    Re: Vizio VT420M No picture

                    Tcon installed no change just a dark blue screen.

                      Comment

                      • tom66
                        EVs Rule
                        • Apr 2011
                        • 32560
                        • UK
                        #26
                        Re: Vizio VT420M No picture

                        It is either the main board or panel then. To find out which you will need an oscilloscope.
                        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

                          • landyboy
                            Badcaps Veteran
                            • Apr 2013
                            • 443
                            • USA
                            #27
                            Re: Vizio VT420M No picture

                            Unfortunately I do not have an oscilloscope. Any other way of testing?

                              Comment

                              • tom66
                                EVs Rule
                                • Apr 2011
                                • 32560
                                • UK
                                #28
                                Re: Vizio VT420M No picture

                                Have you tested all of the main board regulators? If not, do so.

                                If so, then there are very few things you can do without being able to trace the video signal through the TV from the main board to the LCD glass.
                                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

                                  • landyboy
                                    Badcaps Veteran
                                    • Apr 2013
                                    • 443
                                    • USA
                                    #29
                                    Re: Vizio VT420M No picture

                                    I found two regulators on the main board. Using the provided testing procedure. I believe the first one is testing good. The second one:
                                    U702
                                    903T63 L161
                                    Pin 1 0
                                    Pin 2 3.293v
                                    Pin 3 5.115v

                                      Comment

                                      • landyboy
                                        Badcaps Veteran
                                        • Apr 2013
                                        • 443
                                        • USA
                                        #30
                                        Re: Vizio VT420M No picture

                                        I have a bad feeling it may be a panel

                                          Comment

                                          • tom66
                                            EVs Rule
                                            • Apr 2011
                                            • 32560
                                            • UK
                                            #31
                                            Re: Vizio VT420M No picture

                                            Second one appears good.
                                            It can still be a main board problem e.g. bad firmware or some such.
                                            Tab bonds can also cause this.
                                            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

                                              • mikeclarke
                                                New Member
                                                • Dec 2013
                                                • 2
                                                • USA
                                                #32
                                                Re: Vizio VT420M No picture - component cooler fix

                                                I still have sound. Mine works when first plugged in for about 10 minutes then no picture but I still have sound. If I plug in back in again after 3-5 minutes it's still no picture. If I wait 30 minutes it will work again for 5 or 10 minutes.

                                                After it fails if I unplug it and spray component cooler on the mainboard it works almost right away. I normally wait 30-90 seconds before I plug it back in.

                                                I'm posting this pic to help me identify this part. What's inside this thing and what is it? Thanks for your help.

                                                VT420M94501155
                                                CBPF9D1KZ
                                                LC420WUF (SB) (A1)
                                                Attached Files
                                                Last edited by mikeclarke; 03-02-2014, 02:27 PM. Reason: add content

                                                  Comment

                                                  • wriver11
                                                    New Member
                                                    • Sep 2014
                                                    • 2
                                                    • United States
                                                    #33
                                                    Re: Vizio VT420M No picture

                                                    "how do you replace a VIZIO VT420M board".

                                                      Comment

                                                      • wriver11
                                                        New Member
                                                        • Sep 2014
                                                        • 2
                                                        • United States
                                                        #34
                                                        Re: Vizio VT420M No picture

                                                        "how do you replace a VIZIO VT420M t-con board".

                                                          Comment

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