Vizio e420i-a0 main board problems??

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • tbrooks
    New Member
    • Nov 2014
    • 6
    • us

    #1

    Vizio e420i-a0 main board problems??

    Hello all. Just the other day I picked up this tv from a homeowner I work for in trade for a few hours. Now a few months ago, they called and said they were having trouble, it said no signal. So I went up, checked the input, and then switched the hdmi to a different port and it worked. A month later same problem, same solution. Now that was the last port and it stopped working a few weeks ago. I assumed this was a problem with the main board. So a few weeks later I installed a new tv for them and brought this one home. Honestly I was just gonna use it as is and replace my ancient hdtv which didn't have hdmi, so I didn't really need it for my devices. So I turned it on and it started to load up and just froze. And then I heard a noise, kind of a screech, similar to an oscillator sound older tvs had, but a little different. I know some of you may not know that sound as not all people can hear the oscillators. It wasn't very loud, and then the tv turned off.

    Since then I have searched and searched and luckily found this place. Found info in some other threads, and tried powercycles, with various different unplugged time just to see if it made a difference. Also tried holding the input and a few other things. The weird part is it will start up a little differently every time. I've cycled it probably 15 times and it only made that noise above maybe 3 times. Once I even got all the way to a choose store mode or home mode screen. That was the only time the power button actually shut it off, but it wouldn't let me choose a mode. It just seems like it is freezing during the "boot" process (I don't know if that's what it is or is called on these tvs). I'm just not sure if this is a main board problem. It seems as though it would be to me, but this is the first time I've worked on a smart or led or hdtv.

    I read a thread on here about power up issues on another vizio model. It ended up being a firmware problem in most cases and most of the people ended up getting it fixed by Vizio, even out of warranty. Well I contacted them and I wasn't so lucky. I just hope I'm on the right track here, I don't wanna spend to much money fixing this thing.
  • tbrooks
    New Member
    • Nov 2014
    • 6
    • us

    #2
    Re: Vizio e420i-a0 main board problems??

    So I've gone ahead and ordered a new main board, as I have read that will solve the issues of my hdmi problems. As of now the tv won't turn on at all. I have the back off of it now and have visually checked all boards to no avail. Also checked the fuses on the power supply and they are good. Upon checking the connector on the power supply it has the following labels and then my readings
    NC 0volts
    pwm2 0 volts
    pwm1 0 volts
    bl_on/ 0 volts
    ps_on/ 0 volts
    +12 0 volts
    +12 0 volts
    pgnd 0 volts
    pgnd 0 volts
    pgnd 0 volts
    5.2vsb 5.06 volts
    5.2vsb 5.06 volts

    All of these measurements were taken using the frame as ground, hope fully that's ok. I assume that the 5 volts is the power to the main board and that the ps_on/ and bl_on/ (power supply and backlight?) are inputs from the main board to power on the remaining devices. So hopefully I am right and the main board is the source of all my problems.

    Comment

    • budm
      Badcaps Legend
      • Feb 2010
      • 40746
      • USA

      #3
      Re: Vizio e420i-a0 main board problems??

      Main board is still not working, it is not sending any signals to turn on the power supply (PS_ON) or the inverter board (BL_ON, PWM).
      Where did you get this main board from? I hope it has good return policy.
      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

      • tbrooks
        New Member
        • Nov 2014
        • 6
        • us

        #4
        Re: Vizio e420i-a0 main board problems??

        No sorry, misunderstanding. I ordered the main board this morning, these readings were with the original board. I'm hoping that is the only problem.

        Comment

        • tbrooks
          New Member
          • Nov 2014
          • 6
          • us

          #5
          Re: Vizio e420i-a0 main board problems??

          Got the new board finally and installed it. Everything is working perfectly so far!

          Comment

          • Allisun
            New Member
            • Feb 2016
            • 1
            • United States

            #6
            Re: Vizio e420i-a0 main board problems??

            I know this is really old but I am desperate, your story about you TV is the most realtable situation I have read on line about the problems I have. My TV did pretty much the same thing as yours minus the screeching noise which I very well could have looked over. It's been about 8 months TV not working or since the last time a power cycle I tried worked. Ever since then I can't even get it to boot with a power cycle no matter how I've tried it. I just replaced the power supply board in hopes the problem would be redeemed and I could enjoy my television again... However it did no such thing. Not a ding, or dong. Absolutely bummed about it. I was reading and impressed the main board worked for you as initially I assumed that was the issue... I have already thought about purchasing it and stop being a prude but I'm already put of pocket for the power supply board which may not even have been the problem at all... My question to you is, is your TV still in working condition? Was it worth the buy? I just don't know if buying a new TV should just be the only option rTher than buying the main board, it working, and then to stop again months later. Thank you for all the information you've provided so far!

            Comment

            • Gaines
              New Member
              • Jan 2016
              • 6
              • USA

              #7
              Re: Vizio e420i-a0 main board problems??

              Allisun,

              You will receive more help by starting your own thread. There are ways you can narrow down which board is giving you trouble.

              Comment

              • budm
                Badcaps Legend
                • Feb 2010
                • 40746
                • USA

                #8
                Re: Vizio e420i-a0 main board problems??

                Originally posted by Gaines
                Allisun,

                You will receive more help by starting your own thread. There are ways you can narrow down which board is giving you trouble.
                +1, and: https://www.badcaps.net/forum/showthread.php?t=39740
                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

                • brucetv
                  Badcaps Veteran
                  • May 2015
                  • 281
                  • united states

                  #9
                  Re: Vizio e420i-a0 main board problems??

                  I have a Vizio E420i-AO that upon plugging in has a solid blue light that fades to off, and when you hit power backlights come on and then a flash of vertical faint lines on panel, and then back to backlit panel, no picture, no sound. Power supply voltages are
                  Pin 1&2 5.2v
                  3,4,5 Ground
                  6 0
                  7 .002
                  8 0
                  9 0
                  PWM 1 3.2
                  PWM 2 0
                  I will include pics of ps and panel flash with vertical lines at start up. It's the vertical line flash that concerns me regarding possibly a bad panel as well as needing to replace the ps.
                  Attached Files

                  Comment

                  • johnboy1313
                    Badcaps Legend
                    • Nov 2012
                    • 1959
                    • USA

                    #10
                    Re: Vizio e420i-a0 main board problems??

                    Disconnect the ribbons, one at a time, between the tcon and the panel and see if the tv will power on and show a half picture. I suspect you have a failed panel.

                    Comment

                    • brucetv
                      Badcaps Veteran
                      • May 2015
                      • 281
                      • united states

                      #11
                      Re: Vizio e420i-a0 main board problems??

                      Thanks for the quick reply johnboy. I disconnected the ribbon on the left and the left side of the panel is white and I can now see the Vizio logo on the right. I reconnected the left side and disconnected the right and all I get is the backlit panel like picture 3. Bad panel or bad Main since the tcon is on the main on this model. I didn't ever see the Vizio logo when both ribbons were connected.

                      Comment

                      • johnboy1313
                        Badcaps Legend
                        • Nov 2012
                        • 1959
                        • USA

                        #12
                        Re: Vizio e420i-a0 main board problems??

                        Unfortunately, bad panel.

                        Comment

                        • budm
                          Badcaps Legend
                          • Feb 2010
                          • 40746
                          • USA

                          #13
                          Re: Vizio e420i-a0 main board problems??

                          Originally posted by johnboy1313
                          unfortunately, bad panel.
                          +1
                          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

                          • brucetv
                            Badcaps Veteran
                            • May 2015
                            • 281
                            • united states

                            #14
                            Re: Vizio e420i-a0 main board problems??

                            Thanks guys. Now I know how to help diagnose a possible bad panel. We repair gadgets like cell phone, tablets, laptops, ect. but we are learning more and more about Tv's and this forum is the best way to learn from people with years of experience. Thanks again from all us newbies.

                            Comment

                            • Ron.M
                              Member
                              • Aug 2012
                              • 27
                              • USA

                              #15
                              Re: Vizio e420i-a0 main board problems??

                              brucetv;....

                              I'm a retired analog TV repair tech..
                              I HOPE I'm NOT too late to give my Tech advice...
                              I have the SAME model TV as yours...
                              Be advised that the Main board in this model TV does some strange things...
                              Attached are 4 pix that are from the SAME TV & SAME Main board , MINE !!!..
                              ALL 4 pix are from the SAME board !!!..
                              Since there are ONLY 2 boards in this TV , it would be prudent to get a GOOD Main board to try first BEFORE the LED panel is wantonly condemned !!!
                              PLEASE note that the symptom in the pix on the far left side (Vertical lines) was used by another so-called LED expert to condemn my TV when the problem was IDd by ANOTHER Tech as a MAIN board problem & NOT the LED PANEL !!!..
                              A second opinion saved this TV & hopefully I'm right & your TV may have the same problem..
                              Keep in mind that the Main board puts out video for BOTH sides of the LED panel...
                              IF you get video on one side only , there's a chance that the Main board is NOT putting out video for the other side , hence a blank or blue screen..

                              FYI;...
                              A bad LED panel will NOT kill the sound...
                              Bad LED backlights WILL !!!


                              Have a GREAT day & weekend...

                              Later...Ron.M... ...
                              Attached Files
                              Last edited by Ron.M; 04-09-2016, 12:08 PM.

                              Comment

                              • budm
                                Badcaps Legend
                                • Feb 2010
                                • 40746
                                • USA

                                #16
                                Re: Vizio e420i-a0 main board problems??

                                "I disconnected the ribbon on the left and the left side of the panel is white and I can now see the Vizio logo on the right." He gets pictures when only one ribbon is connected, when both ribbons are connected then no longer have pictures on the screen.
                                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

                                Related Topics

                                Collapse

                                • 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
                                • cheeky2
                                  Is it possible to upgrade from a Vestel 17MB97 main board to a 17MB110 Main board?
                                  by cheeky2
                                  I suppose the real question is whether the existing pinouts from ether a 17IPS71 psu are cross compatible with a 17IPS12 psu? If they are then the exchange of the main boards should have no issues providing the screen is compatible with both main boards. Obviously you can change the screen configurations easily enough (providing you have the correct files) for the main board. Why may you ask would I do this? Well a lot of the smart features are no longer working on a Hitachi 48HBT62U main board I wish to give it a new lease of life!
                                  Obviously the same LVDS connector for the screen connection...
                                  05-25-2024, 03:27 AM
                                • 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
                                • Loading...
                                • No more items.
                                Working...