Sharp Aquos LC-C3234U blinking power/OPC lights

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  • mcnaryxc
    Member
    • Nov 2009
    • 13
    #1

    Sharp Aquos LC-C3234U blinking power/OPC lights

    I recently picked up a Sharp Aquos LC-C3234U to fix up from the local thrift store (it's my form of doing puzzles). TV won't turn on when power is pressed. TV immediately shuts off when power is pressed, followed by repeating lights. Power light and OPC lights blink once together, then just power blinks once, and then it repeats. Service manual online doesn't really give any good info, but other Sharp SMs say that the power blinking twice means its a power supply issue. Can't find any schematics.

    Now, I'm pretty sure I found the problem on the board. I looked for shorts on the power supply and found what I think is a shorted MOSFET. When applying my DMM to the source and drain, it shows almost 0 ohms. This is all in-circuit testing, which I know it's not the best thing to confirm problems, but the only other thing that could cause the low resistance is a disc capacitor that's in parallel with the source and drain. Not trying to say it can't be the cap, but I think the MOSFET is more likely the culprit.

    It has K4096 written on it. Here's the data sheet: https://cdn.badcaps-static.com/pdfs/...38d25e7a39.pdf

    My question is: Digikey doesn't have this MOSFET in stock (says obsolete), and the only place I can find any for sale is eBay, where the two on there ship from either China or Malaysia. Is there an equivalent MOSFET I can buy and use instead?

    Thanks!
    Tags: None
    • retiredcaps
      Badcaps Legend
      • Apr 2010
      • 9271
      #2
      Re: Sharp Aquos LC-C3234U blinking power/OPC lights

      Originally posted by mcnaryxc
      but I think the MOSFET is more likely the culprit.
      You should desolder that mosfet and confirm it is shorted. If it is bad, you have to desolder it anyway.

      I have been fooled more than once with in circuit readings despite my best efforts.

      Is there an equivalent MOSFET I can buy and use instead?
      Chat or send an email to digikey. They have live useful folk who can help finding a suitable replacement. Feedback from others who have done this in the past say service is great.
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        Comment

        • mcnaryxc
          Member
          • Nov 2009
          • 13
          #3
          Re: Sharp Aquos LC-C3234U blinking power/OPC lights

          Originally posted by retiredcaps
          You should desolder that mosfet and confirm it is shorted. If it is bad, you have to desolder it anyway.

          I have been fooled more than once with in circuit readings despite my best efforts.
          Ya, that's a good point. I haven't had the time until tonight to really take a good look at the power supply. I'll try desoldering and testing in the morning.

          Chat or send an email to digikey. They have live useful folk who can help finding a suitable replacement. Feedback from others who have done this in the past say service is great.
          Thanks for the tip. I just got done talking to one of their tech support people. They said that while they don't have a direct cross reference to the K4096, they said that this part is the closest match: http://www.digikey.com/scripts/dksea...ywords=AOT8N50

          The Digi-key person said that this MOSFET is like an upgraded version of the K4096. I see that most of the numbers match up or are better (the ones I can understand and think are important like Drain to Source Voltage and Current Continuous Drain), but terms like gate charge and input capacitance are a little different and I'm not familiar with those terms.

            Comment

            • retiredcaps
              Badcaps Legend
              • Apr 2010
              • 9271
              #4
              Re: Sharp Aquos LC-C3234U blinking power/OPC lights

              Originally posted by mcnaryxc
              Thanks for the tip. I just got done talking to one of their tech support people.
              That is great service for a midnight call on potentially a 95 cent item.

              Sorry, I can't help with all the technical specs.
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              We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

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                Comment

                • tom66
                  EVs Rule
                  • Apr 2011
                  • 32560
                  • UK
                  #5
                  Re: Sharp Aquos LC-C3234U blinking power/OPC lights

                  I can't see a problem with that suggested replacement.
                  Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                  For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                    Comment

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