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Acer AL2416 with bad caps

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    Acer AL2416 with bad caps

    Symptom: The backlights will flash on for seconds.
    The bad caps (bulging tops) in the power supply were replaced as a set.
    The 24V, 5V and all the signals are present after new caps are replaced.
    The 24v and the BL_ON are shown up at the inverter board but it still just does the 2-seconds to black. Used a set of test lamps and it still blacks out.
    So I heated up the 10 caps (100uF 35V) on the inverter board with hair dryer, the backlights then stay on.
    Removed all 10 caps and check the capacitance, all are within 20%, check ESR with my home made ESR meter, 4 of them has >10 Ohms. I heated them up with hair dryer, then the ESR dropped down to 0.1 Ohm.
    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

    #2
    Re: Acer AL2416 with bad caps

    Ahh, yes those EVL caps on the inverter board are always prime suspects.
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    Comment


      #3
      Re: Acer AL2416 with bad caps

      The way they mounted those caps, you can't help but think that the board was originally designed for SMD caps. Instead, it looks like they cheaped out and installed lower quality caps.

      Comment


        #4
        Re: Acer AL2416 with bad caps

        That's a very interesting diagnostic technique budm. I might start using the hair dryer technique more often. Besides I don't have enough hair to use it on my head anymore. Might as well put it to good use.

        You got a little lucky because normally the caps on that inverter board take out one of the transistors (P2804BDG or P5504EDG) and at least one of the white smd fuses marked with an "M". I circled them in red for anybody who reads this thread in the future.

        And the last picture with the working monitor made me very happy. Because your workshop looks just like mine. With everything exactly in its right place.
        Attached Files
        Last edited by Lumberjack777; 12-02-2012, 08:05 PM.

        Comment


          #5
          Re: Acer AL2416 with bad caps

          Hair dryer in one of my best tool, been using it since the 70's, and ESR meter sure help explains what I am seeing. That is my work bench at the non-profit electronics recycle (www.crc.org) place that I do volunteer works fixing electronics every Saturday, I get free pizza, been doing this since 1995, hope to get bigger bench but we do not have that much money. All the stuff I work on (and post on photobucket) are all from this place.
          Last edited by budm; 12-02-2012, 08:11 PM.
          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: Acer AL2416 with bad caps

            Originally posted by budm View Post
            Hair dryer in one of my best tool, been using it since the 70's, and ESR meter sure help explains what I am seeing. That is my work bench at the non-profit electronics recycle (www.crc.org) place that I do volunteer works fixing electronics every Saturday, I get free pizza, been doing this since 1995, hope to get bigger bench but we do not have that much money. All the stuff I work on (and post on photobucket) are all from this place.
            I'll bet they are happy to have you volunteering there. I also volunteer for a nonprofit known as Relectronics. We are basically santa's little helpers right now. Getting all the laptops and monitors ready for the kids on Christmas.

            As far as your photobucket database. I have been there many times. It's a warehouse of knowledge. Great job! It's so good to have you, and retiredcaps, jetadm123, Rtech, The_Unique and the others out here to help people.

            Comment

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