Vizio 42" LCD Model SV420M, Black Screen no sound vizio Logo normal

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #21
    Re: Vizio 42" LCD Model SV420M, Black Screen no sound vizio Logo normal

    2.89V is enough to bias on the transistor in the power supply PS_ON line. That flickering may be due to the BL_ON and the PS_ON are on at the same time due to the power supply was not steady yet when the INVETER kicks on at the same time, keep an eye on it.
    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

    • budm
      Badcaps Legend
      • Feb 2010
      • 40746
      • USA

      #22
      Re: Vizio 42" LCD Model SV420M, Black Screen no sound vizio Logo normal

      This is what I have the OP do to his Vizio with bad PS_ON control line by using the BL_ON as the PS_ON controller and a delayed circuits for the BL_ON:
      https://www.badcaps.net/forum/showth...CIRCUIT&page=2
      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

      • MisterD
        Badcaps Veteran
        • Oct 2012
        • 668
        • United States

        #23
        Re: Vizio 42" LCD Model SV420M, Black Screen no sound vizio Logo normal

        Thanks budm, as always you are a great help to me and I appreciate it. The Vizio logo white light stopped flickering for some reason, I have had the tv up and running for 4 hours and still working with no problems ( processor still about 50 degees C at the most ) I did notice that when I had my DVM hooked up and checking voltage at PSON that when I powered on the tv the voltage was instant to PSON and then backlights come on about 2 seconds later.

        Comment

        • MisterD
          Badcaps Veteran
          • Oct 2012
          • 668
          • United States

          #24
          Re: Vizio 42" LCD Model SV420M, Black Screen no sound vizio Logo normal

          Tested on/off many times, left tv on several hours at a time with no problems, checked all inputs HDMI,AV, everything worked but I did find a replacement main board on eBay so I went ahead and got it and installed it, re-wired back to normal, working fine. With this board the normal PSON is 2.26 v when tv is on and .06 when tv is off.
          The processor temp is about the same with either board (120-125)degrees Fahrenheit.

          Comment

          • budm
            Badcaps Legend
            • Feb 2010
            • 40746
            • USA

            #25
            Re: Vizio 42" LCD Model SV420M, Black Screen no sound vizio Logo normal

            Thanks for the follow-up on the repair.
            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

            • MisterD
              Badcaps Veteran
              • Oct 2012
              • 668
              • United States

              #26
              Re: Vizio 42" LCD Model SV420M, Black Screen no sound vizio Logo normal

              You're welcome, so now I know that the main board processor heat sink is normally hot to the touch,after I put it all back together with this new main board I noticed that the backlights and brightness were turned up high, so I turned them down some.

              I was wondering if the processor works harder with more demand, therefore warmer temperature with higher brightness,contrast and backlights?

              Comment

              • budm
                Badcaps Legend
                • Feb 2010
                • 40746
                • USA

                #27
                Re: Vizio 42" LCD Model SV420M, Black Screen no sound vizio Logo normal

                I do not believe so, the power supply and the inverter and the lamps will get hotter at high backlights level (not the Brightness control), there should be Backlights brightness level control on the user menu panel.
                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

                • MisterD
                  Badcaps Veteran
                  • Oct 2012
                  • 668
                  • United States

                  #28
                  Re: Vizio 42" LCD Model SV420M, Black Screen no sound vizio Logo normal

                  Okay, thanks bud, I'm going to save this old main board for a spare since it worked fine with the bypass and 1k resistor.

                  Comment

                  • brairicks26
                    New Member
                    • Sep 2014
                    • 1
                    • USA

                    #29
                    Re: Vizio 42" LCD Model SV420M, Black Screen no sound vizio Logo normal

                    MisterD do you have a better picture of how you did the resistor i have a Vizio SV420M and it did the same thing as yours did i wanna see or know exactly how you did the resistor so i can do it

                    Comment

                    • MisterD
                      Badcaps Veteran
                      • Oct 2012
                      • 668
                      • United States

                      #30
                      Re: Vizio 42" LCD Model SV420M, Black Screen no sound vizio Logo normal

                      Hi brairicks26, Sorry but I don't have a better picture and the tv is gone now, I hope you got yours going.

                      Comment

                      • kisk
                        Computer Tech
                        • Jan 2014
                        • 78
                        • USA

                        #31
                        Re: Vizio 42" LCD Model SV420M, Black Screen no sound vizio Logo normal

                        Just wanted to say awesome thread and thanks for the bypass insight from both of you!

                        Comment

                        • ajkirk66
                          New Member
                          • Jan 2015
                          • 2
                          • USA

                          #32
                          Re: Vizio 42" LCD Model SV420M, Black Screen no sound vizio Logo normal

                          Thanks to this thread, I was able to use this same bypass repair to jumper from U7 to PS-ON with 1K resistor to fix a Vizio SV420M 42" TV. I spent several hours trying to diagnose what was wrong with the main board without identifying the culprit. Everything checked good from capacitors to voltage regulators to diodes etc. I was getting pretty frustrated until I saw this thread. This solution got me up and running in a matter of minutes! It cost me $1.69 for the resistor, so I've decided against replacing or repairing the main board. Thank you Badcaps from a TV repair novice!

                          Comment

                          • 102mm
                            Senior Member
                            • Dec 2013
                            • 181
                            • us

                            #33
                            Re: Vizio 42" LCD Model SV420M, Black Screen no sound vizio Logo normal

                            This TV is crazy.. are we sure it's the main board.. I have the same issue, I checked my power supply and the 12V is only outputting 1.9V at the connector but the 12V is just fine coming out of the FET. SOmeone help please.
                            Craigslist Picks & Fixes

                            2 ea - Samsung 52"
                            Samsung 60"

                            Comment

                            Related Topics

                            Collapse

                            • Tynan Dill
                              Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?
                              by Tynan Dill
                              I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.

                              Upon bringing it home and plugging it up, it showed a standby light.

                              I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.

                              The screen seems to blackout and stay black, but with a flashlight I can see the display.

                              With my Playstation 4 connected via HDMI, and running a game I can hear sound.

                              Assuming...
                              11-22-2024, 01:46 PM
                            • ChaosLegionnaire
                              what i went through dealing with my mobo with dead onboard sound!
                              by ChaosLegionnaire
                              so i took out one of my spare gigabyte ep35-ds3r mobos from storage for use to do some cpu, ram and video card testing of stuff i bought from ebay and got for free from momaka. he bought 50 e8400 cpus for cheap from ebay some years ago and i decided to help him relieve him of some of his supply since he had waaaay too many!! what did we say about hoarding too much stuff and depriving others of them?! *cough* socialism *cough* lol!

                              i had to blow some dust off the board and heatsinks with the datavac as i didnt clean it up before putting it in storage. after finishing...
                              09-13-2022, 09:02 AM
                            • Bob1394
                              Vizio M65-C1 | Logo appears for 10 seconds then off
                              by Bob1394
                              I have used the search, and am stumped.

                              My Vizio M65-C1, Vizio logo appears for about 10 seconds then goes off.Power LED blinks 15 times then the TV powers down.

                              I have read through many threads on the M65-C1 including the following threads. I feel like I must be looking right past the solution to my problem:
                              https://www.badcaps.net/forum/showthread.php?t=81088
                              https://www.badcaps.net/forum/showthread.php?t=84241 (not clear on the Eprom actions)


                              Observations

                              1) [Interaction] Power turned on via TV button (or remote)...
                              02-08-2023, 01:03 PM
                            • Super360
                              Vizio E701i-A3 Vizio logo flashing then turns off
                              by Super360
                              Ok so here's the story. I was watching tv one day when all of a sudden I heard a pop from the back of the tv set and rushed to unplug the set. By this time the tv already had smoke coming out the back. It was not storming or inclement weather that day to cause a power surge to the best of my abilities. When I opened the tv up, I found that the three capacitors on the psu (highlighted in red) were all bulging and looked they had exploded. I replaced all of them right away and when I went to start up the tv after the "fix" it started just showing the flashing vizio logo as soon as power...
                              07-25-2024, 07:06 PM
                            • x_orange90_x
                              Vizio V555-G1 stuck on wallpaper; now stuck on V logo
                              by x_orange90_x
                              I just got this tv today and it's getting stuck on the wallpaper. When I first power it on it goes to the V logo, then a black screen for about 15 seconds, then a Chromecast error for just a few seconds, and then finally to a wallpaper. It stays frozen on this wallpaper and does not respond to anything on the remote besides power on/off. Likewise the buttons on the tv do nothing either (besides power). I did the "reset" by holding the volume down and input buttons together for 10 seconds. It showed a message at the top of the screen saying it was Wiping Data and would restart soon. After...
                              12-28-2023, 06:26 AM
                            • Loading...
                            • No more items.
                            Working...