Vizio SV420XVT1A missing 12v on main board

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • bikerbuddy
    Senior Member
    • Jun 2011
    • 134
    • USA

    #21
    Re: Vizio SV420XVT1A missing 12v on main board

    Sorry If you are confused Budm ,the only time I can see the 12 and 24 volts is when I jump the ps/on to 5v . when I remove the jumper I do not see the 12v nor the 24 v ,

    Comment

    • bikerbuddy
      Senior Member
      • Jun 2011
      • 134
      • USA

      #22
      Re: Vizio SV420XVT1A missing 12v on main board

      U16 and U45 no power

      Comment

      • budm
        Badcaps Legend
        • Feb 2010
        • 40746
        • USA

        #23
        Re: Vizio SV420XVT1A missing 12v on main board

        OK, so the main board is still not sending the PS-ON even though we are getting the correct DCV on the new regulator.
        Looks like we need even more in-depth troubleshooting of the main board at this point.
        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

        • bikerbuddy
          Senior Member
          • Jun 2011
          • 134
          • USA

          #24
          Re: Vizio SV420XVT1A missing 12v on main board

          Ok Budm what would you suggest i try next , remember on post 19 I mention that the main chip with the heat sink is getting hot .

          Comment

          • budm
            Badcaps Legend
            • Feb 2010
            • 40746
            • USA

            #25
            Re: Vizio SV420XVT1A missing 12v on main board

            Without the circuit diagram for the main board, then there is not much you can really do at this point since all we are able to test are the regulator ICs, and they are OK at this point. I think you will have to get new 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

            • bikerbuddy
              Senior Member
              • Jun 2011
              • 134
              • USA

              #26
              Re: Vizio SV420XVT1A missing 12v on main board

              Yes Budm after I felt the heat on the main chip I figure I will have to go that way also , any way thanks and I will post how I conclude this post later

              Comment

              Related Topics

              Collapse

              • Dani_2024
                Sceptre U550CV-UMR 4K LED, Bad Caps on Main Power Board?
                by Dani_2024
                Hi and thanks in advance for any input you might provide!
                I have a Sceptre U550CV-UMRD8POTV83BB 4K LED (this is a dumb tv) that I bought new in August 2021, so It's just completed 3 years.
                Main power board model: TP.MS3683.PC821 T-Con board: N4TP546UHDPU2L_BO

                Last Sunday I was watching a dvd and fell asleep for about half hour, when I awoke the tv screen was black and couldn't get the dvd menu to show, so I changed the input to antenna and had sound but no picture, turned it off. I then got online and found this great site! ....read many troubleshooting tips and this...
                10-28-2024, 05:06 PM
              • ygorsan
                LG 55NANO77SRA TV – Menu scrolling by itself even after removing button board (Main Board EBU66792103)
                by ygorsan
                Hi everyone,




                I’m looking for help with a persistent issue on an LG TV model 55NANO77SRA, which uses the main board EBU66792103 (also used in LG UQ80 and NANO75/NANO80 series).







                🧩 Problem Summary:
                • The TV keeps scrolling through the menu or selecting items by itself.
                • I removed the physical button board (the entire panel with power and volume buttons) and also disconnected the flat cable (CN202) from the main board.
                • The remote control is not in use (batteries removed), and the TV still shows the same behavior.
                • I
                ...
                07-28-2025, 08:34 AM
              • jb_Bak
                Sony xbr-65x900c main board issues?
                by jb_Bak
                Hey guys great forum glad to have found it. I bought a Sony XBR 65X900C cheaply because it didn't work. No signs of life at all not even a light/led. All I hear is a brief high voltage sound when I throw the power to it.

                Didn't see any obvious signs of damage so right away started checking voltages. This is what I see:
                Power Board Connector that goes to Main board
                CN6401
                Pin 01 NC
                Pin 02 NC
                Pin 03 "BL_ON": 0V
                Pin 04 "N/C"
                Pin 05 "STBY 3.3V": 3.5V
                Pin 06 "GND": N/C
                Pin 07 "AC_OFF"...
                09-27-2021, 04:52 PM
              • JDC
                (SOLVED) - ONN 100012588 No Power, Then Rebooting After Main Board Change
                by JDC
                ONN 100012588
                Issue: No Power, Then Rebooting After Main Board Change

                Short answer: replace main board and power board
                Technical answer: replace main board and Q306 & Q307 on power board.

                Long answer:

                TV wouldn't turn on. Power switch was fine which means the main board isn't processing the power on signal. Replaced main board. TV turns on now but randomly reboots. Bad main board? EEPROM? Tried to pull main board and got a shock touching the corner of the board. That's weird. C334 (450V 10uf) capacitor is still holding a high charge....
                07-15-2022, 07:39 AM
              • m1ch43lzm
                HP Pavilion 15-eh Board DAG7HAMB8F0 - CPU throttling to 0.4GHz (PROCHOT_EXT) and black screen
                by m1ch43lzm
                Hi, this is my personal laptop, which the original board (lets call it Board A) blew up PU8700 (TPS51486), making a hole on the board, i had left the laptop at my desk one day with the battery fully charged and didn't touch it for a week, but when i tried to turn it on it didn't
                Thought the battery was dead, so i plugged in the charger then tried to power on, the power LED blinked once, charged LED still orange, unplugged the charger, plugged in again and I noticed the "magic smoke" smell, so i unplugged the charger, removed the back cover and saw the blown IC (the "magic...
                05-12-2025, 08:37 PM
              • Loading...
              • No more items.
              Working...