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Vizio vt420m turns on logo comes up and is unresponsive

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    Vizio vt420m turns on logo comes up and is unresponsive

    The tv has been acting funny for a while. It started when the sound went out internally however audio out still worked. After a while the tv reset itself and the sound started working again. Within a few weeks the tv began periods of not turning on or having to turn the tv on and off for a few minutes to get it to kick in. Often times what i did to get it to work was unplug it for a while. While this was going on the tv also started to randomly shut itself off however if i remember correctly the couple times it did it i was watching a movie through hdmi and the optical audio output going to my receiver still was sending the signal through as the sound did not die out. Very random and sporadic errors. Now the tv will not turn on at all.

    What is currently happening is when you click the power button the tv power on the lcd is backlit and the vizio logo pops up like it typically does when you turn it on however it gets stuck there and is unresponsive besides turning it back off. It sometimes did this when it was going through the period of having to turn it on and off multiple times to get it to stay on or having to leave it unplugged.

    I have taken the back off the tv off and looked over the boards and cannot seem to see anything that looks out of place. looked for bad caps and any burnt joints. I am attaching some pictures so maybe someone more experienced may be able to pick something out.

    I have a multimeter however am not really sure what to check for. I am much more of a mechanical based person than electrical but have been learning quite a bit recently in school in from an engineering measurements class dealing with fundamentals of digital electronics.

    All help is appreciated and i will do what i can to help you help me thanks

    Here is a video of what happens

    http://www.youtube.com/watch?v=4ushqXE5kfI

    and some pics of the boards let me know if any other videos or pics would be helpful








    Another thing i noticed is that when i unplug the top board the tv still powers up screen turns on but no vizio logo pops up. I am new to this stuff so not sure if thats normal or what.


    Thanks
    Last edited by davedude44; 04-25-2012, 08:49 PM.

    #2
    Re: Vizio vt420m turns on logo comes up and is unresponsive

    ..........

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      #3
      Re: Vizio vt420m turns on logo comes up and is unresponsive

      up

      Comment


        #4
        Re: Vizio vt420m turns on logo comes up and is unresponsive

        Can you get a better photo of the main board? Try and get it as close to 2000 x 2000 and upload it using manage attachments. After you turn the tv on and it hangs can you turn it off or do you have to pull the plug?

        Comment


          #5
          Re: Vizio vt420m turns on logo comes up and is unresponsive

          Can you please remove the pictures and please use the attachment function to post the pictures instead? It takes a long time to get the web page up due to loading of the pictures, this will discourage other people to answer the questions, thanks.
          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


            #6
            Re: Vizio vt420m turns on logo comes up and is unresponsive

            I think the problem is in the eeprom memory u2

            measure the pulse on pin 5 and 6 and to change the channel has changed pulses . if it is not damaged

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