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Acer AL1717F blue led does not turn on

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    Acer AL1717F blue led does not turn on

    Hi all,

    I have this Acer AL1717 F working lcd monitor, but yesterday the blue led light on the front switch doen not turn on and thus no display on screen. Upon opening the outer casing, and looking at overall board (image 112637), i do not see any burned parts or bulge caps. Fuse T2A measured with continuity.
    The main caps has around 340vdc. Tha main board(image 113242) has vcc 5vdc on pin 1&2 on the red wire. I would like to understand what is going bad and to request for any guide and kind help to replace or repair the bad faulty part instead of throwing this monitor to dump. Any generous assistance in the right direction is highly appreciated.
    Attached Files

    #2
    Re: Acer AL1717F blue led does not turn on

    Hi!
    How many volts when turned on
    CN801 pin4 ?
    L802 ?

    Comment


      #3
      Re: Acer AL1717F blue led does not turn on

      Hi kasfamily,

      Thanks for reply.
      CN801 pin 4(on/off)=0.00vdc
      L802=13.9vdc

      Glad if you can assist me further in bringing this monitor to life again.

      Comment


        #4
        Re: Acer AL1717F blue led does not turn on

        Show a photo of the motherboard from the parts side

        Comment


          #5
          Re: Acer AL1717F blue led does not turn on

          Originally posted by kasfamily View Post
          Show a photo of the motherboard from the parts side
          Attached the photo of main board and logic board from the parts side.
          Attached Files

          Comment


            #6
            Re: Acer AL1717F blue led does not turn on

            Sorry, I said it badly, you need a clear photo of only a small board ( logical, with a processor )

            Comment


              #7
              Re: Acer AL1717F blue led does not turn on

              Originally posted by kasfamily View Post
              Sorry, I said it badly, you need a clear photo of only a small board ( logical, with a processor )
              Is ok, no problem .
              Attached a clear photo of small board (logical with a processor).
              Glad that you can assist.
              Attached Files

              Comment


                #8
                Re: Acer AL1717F blue led does not turn on

                How many volts per pins u101 and u102

                Comment


                  #9
                  Re: Acer AL1717F blue led does not turn on

                  Originally posted by kasfamily View Post
                  How many volts per pins u101 and u102
                  U101 pin 2= 6.12v
                  pin 3=11.05v
                  pin 4= 5.14v

                  U102 pin 2= 3.18v
                  pin 3=10.69v
                  pin 4= 3.31v

                  Both pins 1 reads 0v

                  Comment


                    #10
                    Re: Acer AL1717F blue led does not turn on

                    need a clear photo of the parts in the red circle, so that the marking can be read
                    Attached Files

                    Comment


                      #11
                      Re: Acer AL1717F blue led does not turn on

                      Originally posted by kasfamily View Post
                      need a clear photo of the parts in the red circle, so that the marking can be read
                      Attached a clear photo of your request.
                      Appreciate your kind assistance.
                      Attached Files
                      Last edited by mikey5791; 04-11-2021, 08:49 PM. Reason: Add photo

                      Comment


                        #12
                        Re: Acer AL1717F blue led does not turn on

                        On a small board (logical with a processor), where did the voltage of 11 volts come from? It only supplies 5 volts ! What is the marking on the U101 and U102 ?
                        Attached Files

                        Comment


                          #13
                          Re: Acer AL1717F blue led does not turn on

                          Originally posted by kasfamily View Post
                          on a small board (logical with a processor), where did the voltage of 11 volts come from? It only supplies 5 volts ! What is the marking on the u101 and u102 ?
                          u101=ld1117a
                          l33auc

                          u102= a1
                          as1117l-18
                          b0703 b6
                          Attached Files
                          Last edited by mikey5791; 04-12-2021, 07:30 PM. Reason: Add photos

                          Comment


                            #14
                            Re: Acer AL1717F blue led does not turn on

                            The 3-pin U101 and U102 must have 5 volts ! The 4-pin U101 must have 3.3 volts ! The 4-pin U102 must have a voltage of 1.8 volts. I repeat the question-where did the 11 volts on this board come from ?

                            Comment


                              #15
                              Re: Acer AL1717F blue led does not turn on

                              Originally posted by kasfamily View Post
                              The 3-pin U101 and U102 must have 5 volts ! The 4-pin U101 must have 3.3 volts ! The 4-pin U102 must have a voltage of 1.8 volts. I repeat the question-where did the 11 volts on this board come from ?
                              Yesterday night i redo the voltage test, this time I test it twice with following results:
                              Sorry for the misleading results of 11 volts earlier on.

                              U101 pin 2=3.10
                              pin 3=4.70
                              pin 4=3.10

                              U102 pin 2=1.60
                              pin 3=4.70
                              pin 4=1.60

                              Comment


                                #16
                                Re: Acer AL1717F blue led does not turn on

                                It is necessary to check or change all the capacitors in the 5 volt / 3.3 volt / 1.8 volt circuits for new ones . These voltages should be exactly the same and without AC ripples

                                Comment


                                  #17
                                  Re: Acer AL1717F blue led does not turn on

                                  Originally posted by kasfamily View Post
                                  It is necessary to check or change all the capacitors in the 5 volt / 3.3 volt / 1.8 volt circuits for new ones . These voltages should be exactly the same and without AC ripples
                                  Hi,

                                  May i know which capacitors are for the 5 volt, 3.3 volt and 1.8 volt circuits? Can you kindly guide me how to verify which caps are for certain circuit because i totally have no knowledge on this. For your info, i do not have access to an oscilloscope and may not be able to check on the AC ripples. Is there another way to check AC ripple?

                                  Btw, earlier i had desoldered off board those medium size brown Suscon caps marked at c809, c812, c808, c826, c810 and c522 at power supply board. I used an esr meter and tested all those 6 caps esr read 0.00(low good esr) and uf reading do not exceed more than 5% of what was printed on caps.
                                  Glad that you can offer your help on reviving this monitor.

                                  Comment


                                    #18
                                    Re: Acer AL1717F blue led does not turn on

                                    Hi forum friends,

                                    Anyone can help me on this?

                                    Comment

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