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Vizio M701d-A3R M701D image; no backlight

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    Vizio M701d-A3R M701D image; no backlight

    I was gifted this monstrous non-working 70" Vizio. The story goes that it was working flawlessly for 6 years and then one day the screen was black. "Just needs a an inexpensive board!", I was told! Bwahaha! Unfortunately my extensive internet research has not provided me an answer as to exactly which board I might replace! This particular Visio has relatively few posts on Badcaps, though there is a robust thread from throngs of owners that had the opposite problem from mine (backlight but no image) and board replacement was NOT the solution.

    This TV has 3 Sharp boards (not counting the T-con board—which is still under cover at the bottom of the unit): main logic board - 1P-0133c00-4012; LED driver 05-70COR000-00; and power supply E93938 1P-1133800-1011.

    The unit powers on. The logic board appears to go through a self test (red LED on board flashes once and then stays on). I see no visibly damaged components on either side of the boards. The flashlight test shows that I have an image on the screen. (I don't have a proper audio/video feed in my shop, yet—I'm a pinball guy, not a TV guy!) but I can see with my flashlight a "no signal" message. I plugged in a USB flash drive with images and it appeared to be accessing that. I had hoped that there were more test points with labeled voltages on the boards... I only see 12v markings on the power board and these are present. No other voltages labeled, dammit, but I see .

    I realize this is rather scant information. At one point shopjimmy.com had all three boards for $135 (now, out of stock). If that were an option, I'd gladly take the shotgun approach to this repair! I am hoping one of you pros will have seen this scenario and will immediately point me to the likely culprit (though the Web shows no postings anywhere with this exact unit/issue)!

    I know it's never this easy! I am anxious to provide any further diagnostic data. Thanks in advance!

    Lance

    #2
    Re: Vizio M701d-A3R M701D image; no backlight

    Please attach good clear pictures of the whole backside of YOUR TV so we can see all the boards and how they are connected together so we can see what we are dealing with.
    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


      #3
      Re: Vizio M701d-A3R M701D image; no backlight

      Thanks, Bud. Images attached.
      Attached Files

      Comment


        #4
        Re: Vizio M701d-A3R M701D image; no backlight

        Check if you're getting an output from the power supply to the LED driver because I'm not. I'm also having an issue with the same problem. I checked the backlights and they're working with the tester.
        Attached Files

        Comment


          #5
          Re: Vizio M701d-A3R M701D image; no backlight

          Try accessing the menu while shining a flashlight on the screen and turn the backlights down. See if they pop on. If so there may be one/some LEDs breaking down under high current.

          If this doesn't work, don't discount the possibility the backlights are bad. This is just one simple test I use to make it a bit easier to diagnose bad LEDs. It doesn't always work tho.
          They call me......."threadkiller"

          Comment


            #6
            Re: Vizio M701d-A3R M701D image; no backlight

            Thanks for your replies. Attached are voltages power board-to-LED board.

            I perviously attempted to access (and see) menu... will give that another go.

            Thanks, again,

            L
            Attached Files

            Comment


              #7
              Re: Vizio M701d-A3R M701D image; no backlight

              Originally posted by Plurxtc1 View Post
              Check if you're getting an output from the power supply to the LED driver because I'm not. I'm also having an issue with the same problem. I checked the backlights and they're working with the tester.
              You are fortunate to have a means of checking your backlights. Are you thinking your problems are all caused by your power supply? I suppose with no idea if my LEDs are working, it's fairly difficult to continue?

              I'm getting a good education here... that I don't know squat about what I'm looking at!

              Thanks,
              L

              Comment


                #8
                Re: Vizio M701d-A3R M701D image; no backlight

                Originally posted by DXseekerMO View Post
                Try accessing the menu while shining a flashlight on the screen and turn the backlights down. See if they pop on. If so there may be one/some LEDs breaking down under high current.

                If this doesn't work, don't discount the possibility the backlights are bad. This is just one simple test I use to make it a bit easier to diagnose bad LEDs. It doesn't always work tho.
                I spent some time messing around in the menu. I didn't affect any change, but I am honestly uncertain of where I was and what I was doing!

                Probably in over my head! Thanks!
                L

                Comment


                  #9
                  Re: Vizio M701d-A3R M701D image; no backlight

                  Replacing the power supply fixed it. 80V shows up on the capacitor to the backlight and the lights came on.

                  Comment


                    #10
                    Re: Vizio M701d-A3R M701D image; no backlight

                    Great job! Thanks for updating
                    They call me......."threadkiller"

                    Comment


                      #11
                      Re: Vizio M701d-A3R M701D image; no backlight

                      I want to provide some closure to this thread. I took the Vizio to a proper tech. He determined that it was the LED backlights that had failed. For $320 he replaced the LEDs and the TV is working and looks fantastic. So... a 6 year old $2000 TV for $320! Winner! Thanks all for your help!

                      L

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