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p50 hdtv20a

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    #21
    Re: p50 hdtv20a

    u3 az7805t 12.13 0 5.05
    u4 amc1117 f0745 4.6 3.3 2.05
    u2 " '' 4.6 3.27 2.03
    u8 5.07 3.31 2.06
    u33 4.6 2.05 1.27
    u7 2.05 1.01 .02
    u9 k117s15 737 2.05 1.18 0
    u35 amc1117 f045 4.6 3.28 2.04
    u10 1084 01717dl 4.59 1.34
    this is one with just 2 pins center one cut off


    Its not pretty but here it is.
    my old eyes cant read u8 u33 or u7 and im not 100% sure the other part#
    are correct either. I may need a better magnifying glass.

    Comment

      #22
      Re: p50 hdtv20a

      Originally posted by acuser View Post
      u33 4.6 2.05 1.27
      u7 2.05 1.01 .02
      u9 k117s15 737 2.05 1.18 0
      u10 1084 01717dl 4.59 1.34
      U33, U7, U9, and U10 are all suspect. Recheck your readings and see my how to test a voltage regulator document for further explanation.
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      Comment

        #23
        Re: p50 hdtv20a

        I retested the four suspect regulators and got the same readings. I think this is the confirmation I was looking for.

        I'm not sure I have the skill to replace such small components, so i think I will just order the board.

        I will post back the results after receiving the board.

        Thanks for all the help

        Comment

          #24
          Re: p50 hdtv20a

          If you look again at your readings, U33 is probably the only potential bad one. The output of U33 is incorrect and in turn becomes the input for U7 and u9. You might as well take a shot at removing U33 only and seeing if that fixes your problem.

          For U10, I can't tell 100% if that is good or bad based on the part number you have provided.
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            #25
            Re: p50 hdtv20a

            Hey guys thought I would post update. Replaced the voltage regulator at U33
            Set works great. I could not have done it without everyones help here.
            Great forum....Thanks guys

            Comment

              #26
              Re: p50 hdtv20a

              Originally posted by acuser View Post
              Replaced the voltage regulator at U33
              Set works great.
              I have speculated on this before, but I lack the knowledge and expertise to know for sure.

              Either Vizio bought the voltage regulators from the worst manufacturer in the world or the engineers underdesigned the circuitry around the voltage regulator causing it to fail way faster than it should.
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              Comment

                #27
                Re: p50 hdtv20a

                If only U33 fails, it points to a design flaw -- most likely, the regulator runs far too hot and the inferior regulators they use fail. A good regulator would not fail. However, looking at the amTRAN board design, it looks like it was done really cheaply; by using lots of regulators instead of a few small, efficient, reliably buck converters, to save a few tens of cents.

                I have also found a failed regulator on a Samsung LCD t-con, and on the main board in a Bush (Haier) LCD TV.
                Last edited by tom66; 11-24-2012, 04:15 PM.
                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.

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