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no LED or power on Acer AL1716

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    #1

    no LED or power on Acer AL1716

    i'm having an issue with this monitor that uses a TDK XAD819AR power board.

    when plugging in the power board to mains, i'm not getting +12v on the 8-pin header. instead i get between 6-7v.

    +5v is working.

    160v on main cap

    i've replaced all the caps, and verified the 12v regulator is working (IC53).

    is there anything else i can check? or does anyone have a link to the schematic for this board? i've scoured elektrotanya and none of the service manuals seem to reference this power board.

    thanks for any help you can provide!
    Last edited by digidelia; 10-05-2012, 01:52 PM.
    Tags: None
    #2
    Re: no LED or power on Acer AL1716

    also, i have to add, i hear a soft "clicking" when the mains is plugged in. i can't really narrow down where it's coming from

    Comment

      #3
      Re: no LED or power on Acer AL1716

      Well, since there is no schematic and the board is sitting in front of you, the folks that would normally provide assistance are at a slight disadvantage, since they have nothing to look at or reference. Please provide top down photos of the entire power board top and bottom. Use "manage attachments"
      to post them.

      The ticking sounds like the power supply is trying to start. Possible bad startup cap. Does the 12V output go up to 7V then drop to 0V? Then repeat itself?
      Last edited by jetadm123; 10-05-2012, 03:55 PM.

      Comment

        #4
        Re: no LED or power on Acer AL1716

        yeah, sorry about that. here are some pics of the board.

        as far as i can tell, the 12v floats around 6-7v. i don't have access to a waveform scope at the moment for a better explanation.
        Attached Files

        Comment

          #5
          Re: no LED or power on Acer AL1716

          I would try replacing those two caps first.
          You can also run the power supply without having the main board connected, the power supply board is always on the minute you plug it into the outlet, and see if the 12V and 5V are steady.
          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

            #6
            Re: no LED or power on Acer AL1716

            Originally posted by digidelia View Post
            i've replaced all the caps,
            In your pictures, it doesn't look like you replaced any of them?

            As budm alluded to, does all mean all?
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            If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

            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.

            Please do not post inline and offsite as they slow down the loading of pages.

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            Comment

              #7
              Re: no LED or power on Acer AL1716

              i've replaced everything except C5, the large cap laying on its side...

              Comment

                #8
                Re: no LED or power on Acer AL1716

                Originally posted by digidelia View Post
                i've replaced everything except C5, the large cap laying on its side...
                It's been awhile since I have seen that board but if I remember correctly the smaller capacitors at C57 and C62 and the other small cap inside the heat sink wall will develop high ESR and maybe bulge. That design is a total heat trap.
                You'll need to test CR51 and CR52, and possibly WJ10 for shorts. ORRRRRRRR you can buy a new board for 19 bucks and wait 2 weeks. When the price of caps and component equals the price of a new board I just get a new board. But you can solder on the good caps and it'll probably last a long long time. http://www.ebay.com/itm/TDK-Power-Bo...item3f1ac17fff

                Just a suggestion! Good luck! L-J-7

                Comment

                  #9
                  Re: no LED or power on Acer AL1716

                  I am replacing caps on power board, model XAD819AR, for an Acer LCD monitor, model AL1916. The board has been repaired by someone else previously, and I'm concerned that I'm replacing capacitors of incorrect capacitance. All of the repair kits that I have seen have two 1000μf caps listed, but the board I have doesn't have any of those on it. I think they may have been improperly replaced.

                  I need help locating the correct placement of the 1000μf capacitors on this board.
                  Attached Files
                  Last edited by bboettner; 10-15-2012, 04:29 PM. Reason: Adding Image

                  Comment

                    #10
                    Re: no LED or power on Acer AL1716

                    FYR
                    https://www.badcaps.net/forum/showthread.php?t=12716

                    C54 & C56

                    Comment

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