Announcement

Collapse
No announcement yet.

Logic board repair help needed please please

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Logic board repair help needed please please

    Hi

    I am in need for some help to fix my old Macbook Pro ( 17", A1229, 2.ghz)

    The Macbook pro was working fine until recently when I had to check the fans and sensors due to AHT reporting one was not working.
    So I opened it up and done some cleaning and went to boot it up which it did but got the black screen, no chime, solid white light on the latch in the front, no back light but fans turn on and hard drive spins up.
    I done the PRAM and SMC reset but not no luck

    I was puzzled so I done some research and everyone suggested do a reflow, so i followed the ifixit guide but no luck,

    I put everything back together and to find a weird problem that i have to press the power button 3 times or more to get it to start. Everytime I press I see the fans move a little and hear the hard drive click but doesnt start up
    after few more presses it does start up but with same symptoms, black screen, no back light, solid white light on latch, no chime.

    I took the top case off and tried starting macbook by jumping power on pads.same thing have to keep pressing the pads a few times before it starts, Also before the SYS RST pads used to restart the laptop but that does not work neither

    I checked the RAM, one by one in each slot, the charger.
    Charger has green light


    Same thing happens when powered by battery
    I downloaded the schematic diagram, found via a google search and started measuring and following the flow of power as seen on page 3. Measuring voltages on all the power lines but I am hoping you can help me on what points to measure and if it requires me to replacing components then I can do that, I have a multimeter and access to a oscilloscope

    I really don't think it is anything major, I think it is a capacitor, resistor or chip that has gone.
    I know these models had the nvidia problem and people repair them but I want to repair it myself with your help
    Apple store do not repair these any more.

    I was hoping if someone can help me please
    I will appreciate it so much

    I look forward to your reply

    Many Thanks
    Kind Regards

    #2
    Re: Logic board repair help needed please please

    mainboard type number ?

    Comment


      #3
      Re: Logic board repair help needed please please

      HI
      It is 820-2132-A
      If anyone has a board view for this It will be really appreciated as well please

      Thanks for the reply
      So much
      Thanks in advance

      Comment


        #4
        Re: Logic board repair help needed please please

        inspect the board for a simbol on mainboard for turn on and off like the one on remote for tv ecc ecc. when u find it post picture.

        Comment


          #5
          Re: Logic board repair help needed please please

          hi
          what do you mean
          the pads

          Comment


            #6
            Re: Logic board repair help needed please please

            Originally posted by lcdcaps1 View Post
            hi
            what do you mean
            the pads
            yes 2 pads with that symbol near them.

            Comment


              #7
              Re: Logic board repair help needed please please

              there are two pads and has PWR ON
              also another two that have SYS RST

              Comment


                #8
                Re: Logic board repair help needed please please

                post picture on this thread. attach them

                Comment


                  #9
                  Re: Logic board repair help needed please please

                  Attached are pics of PWR ON AND SYS RST PADS
                  If any one has the board view file for the 820-2132-A motherboard I Will be so grateful if it can be shared or uploaded or sent by PM please. Many Thanks in advance
                  Attached Files

                  Comment


                    #10
                    Re: Logic board repair help needed please please

                    short 2 power on pads and see if macbook power on like normal. if it power on, but no display, check if cpu and chipset and gpu get hot.

                    Comment


                      #11
                      Re: Logic board repair help needed please please

                      Hi
                      As stated in my first post I was jumping these pads and there is not reaction.
                      No fans, no chimes, no back light, no video (black screen), solid white light on latch.

                      The sys rst pads does not do anything neither
                      I don not think the cpu and gpu get hot

                      Comment


                        #12
                        Re: Logic board repair help needed please please

                        if it didnt power on, checl for 3.3volt if it is present . tipically it is a tps51125 check for that voltage on the inductor near it.

                        Comment


                          #13
                          Re: Logic board repair help needed please please

                          I will Check and.report back
                          Can you confirm.which inductor I should test. Will there only be.one on the 3.3v line (

                          Comment


                            #14
                            Re: Logic board repair help needed please please

                            When you say you reflowed the board what exactly did you do to it?
                            It sounds like there may be a problem with the SMC. This is a microprocessor which manages various power states, I believe it also deals with sensor outputs. It is a 3mm ball grid array I believe so the usual caveats with BGA apply. I believe it is U4900. You can check you have stable G3h which is 3.42V then you can also check the input to SMC which is 3V or 3.3V.

                            Comment


                              #15
                              Re: Logic board repair help needed please please

                              hi
                              can i use the test points to test the smc
                              also i cannot find the inductor to test and cannot find tps51125
                              please help
                              thanks so much

                              Comment


                                #16
                                Re: Logic board repair help needed please please

                                HI
                                Sorry it has taken me so long to reply
                                I have an update
                                The Macbook pro now turns on for a few seconds, the hard drive spins and fan starts and then off by its self if when I plug in the charger. If only the charger is connected it will not turn on by jumping the pads but when I plug in the battery only the power button works first time press.

                                I am more confused on whats going on
                                please can some one help me

                                Thanks
                                Waiting for everyones reply

                                Comment


                                  #17
                                  Re: Logic board repair help needed please please

                                  probably a short on dcin line. we need schematic and board view to help u out. i assume one of 2 fets that supply 12.5 volt are shorted. post picture of board bottom and low picture in high quality.

                                  Comment


                                    #18
                                    Re: Logic board repair help needed please please

                                    HI

                                    Thanks for the reply
                                    You can view the schematic here


                                    I do not have the board view.
                                    Can you tell me which mosfets I need to check. Also is it is a case of just checking voltage measurements according to the schematic.

                                    Comment


                                      #19
                                      Re: Logic board repair help needed please please

                                      L7900 check if it's shorted.
                                      check voltage u7900 pin 1 and 25.

                                      Comment


                                        #20
                                        Re: Logic board repair help needed please please

                                        Will check and report back
                                        Thanks

                                        Comment

                                        Working...