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Sharp TV LC-40LE820X Shutting off on TV function.

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    #1

    Sharp TV LC-40LE820X Shutting off on TV function.

    Hi guys I have a sharp LC-40LE820X, and the main power board is a DPS-126CP B.

    Back ground info, is the in-laws bought this TV new for the London Olympics IIRC, so around 2012.

    When on TV function, after a period of time (20 minutes or so) the picture becomes choppy, then appears to turn off: When I try to turn it on it then has a warning similar to "service has been changed, execute auto install".

    But I can display pictures from a usb on rotation for hours on end.

    Given this, I suspect a power supply issue: Does this sound right? Or a tuner issue is possible I guess.

    I've looked over the main power supply board, initially I only looked at the large cylinder type capacitors, none of them are bulging/split, but after dusting off, I believe the flat capacitor C7813 is cracked.

    Open to advice, thanks in Advance
    Aussie_Matt
    Tags: None
    #2
    Re: Sharp TV LC-40LE820X Shutting off on TV function.

    If there was only a way we could see that board... If the C7813 is cracked, replace it and see if it fixes the issue, normally a power supply fault would effect all inputs not just the tuner. I doubt that capacitor would cause this problem based on its location in the circuit.
    Have you tried a hdmi input to see what effect that has?
    Last edited by R_J; 08-03-2019, 08:42 AM.

    Comment

      #3
      Re: Sharp TV LC-40LE820X Shutting off on TV function.

      Since it takes 20 minutes to become "choppy", it could be a heat related problem. Try heating each board with a hair dryer to see if you can get the failure to occur sooner.

      Comment

        #4
        Re: Sharp TV LC-40LE820X Shutting off on TV function.

        If C7813, is bad , it could be that the pfc circuit is damaged and the tv "might" still operate, So check the voltage across the main filter capacitor (C7800) both in standby and when the tv is turned on. It should be around 350vdc in standby and go up to around 400vdc when the tv is turned on. If it does'nt, check if R7816 is open or not.

        Comment

          #5
          Re: Sharp TV LC-40LE820X Shutting off on TV function.

          Hi all. Apologies for slow reply.

          Please see attached pic of main power board. I'm yet to test the TV using a HDMI source to see if the behaviour is replicated, I know it's ok running pictures of a Hard disks, but I'm not sure about HDMI, so I'll try that.

          Thanks.
          Attached Files

          Comment

            #6
            Re: Sharp TV LC-40LE820X Shutting off on TV function.

            Originally posted by R_J View Post
            If C7813, is bad , it could be that the pfc circuit is damaged and the tv "might" still operate, So check the voltage across the main filter capacitor (C7800) both in standby and when the tv is turned on. It should be around 350vdc in standby and go up to around 400vdc when the tv is turned on. If it does'nt, check if R7816 is open or not.
            Thanks for that.

            I have no voltage across two capacitors: 7800A and 7800B, are these what you mean?
            As for R7816, that resistor is half under a heatsink for some transistors/regulators. I guess I should remove the board and probe it from the other side?

            Comment

              #7
              Re: Sharp TV LC-40LE820X Shutting off on TV function.

              If you have no voltage across C7800a OR C7800b there is not way this power supply will work so the tv can not be working at all.
              Just check the voltage across the + and - of C7800 (this is one of two main filter capacitors)
              to measure the resistance of R7816, place one probe on the end of the resistor that stick out from under the heat sink and the other probe on C7800 negative lead.
              Last edited by R_J; 09-21-2019, 10:31 AM.

              Comment

                #8
                Re: Sharp TV LC-40LE820X Shutting off on TV function.

                DPS-126CP A schematic may be closed enough.
                Attached Files
                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

                  #9
                  Re: Sharp TV LC-40LE820X Shutting off on TV function.

                  In the end this sets behaviour was just erratic, so I took it to a local repair bloke: He diagnosed the motherboard as the fault, and not the PSU as suggested by you guys.

                  But long story short, apparently that exact board isn't available, so there is a superseeded number, he got that in, and it wasn't "suitable."

                  So I'm out $50, but I'm more than happy with that. I could've messed around for hours (more than I already did) and come up with the same result.

                  But, I would have liked that TV to work as it had component input, and I have 'too many' older gaming consoles that don't like HDMI convertors that much.

                  I guess I need to go TV shopping.... I just bought a PS4 Pro, with 4K support, so that will be nice to use too.

                  Comment

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