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MBA A1466 820-00165 no green light, no boot

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  • MBA A1466 820-00165 no green light, no boot

    This board had some sticky food stuff around C7796, I resoldered the cap after cleaning up the area.
    However, the problem, no green light on mag and no boot remains. Turns out the mag adapter is dead as well, so I am using a MBP mag adapter and want to ask, to make sure that this is not going to do further damage?
    With that working MBP mag in place, and with battery plugged in I have voltage as per specs on all PPDCIN_G3H up to Q7010, but nothing gets past.
    Being very new at this I am hesitant to induce voltage, I do not want to fry things.
    What would you suggest I do from here?

  • #2
    Are you using original Magsafe 2 60/85W charger?
    Don't use 1-->2 adapter.

    Post exact voltage for PPBUS_G3H (F7140) and 3V42 (L7095).
    Also check SMC_RESET_L, SMC_ADAPTER_EN, PM_BATLOW_L, PM_SLP_SUS_L, 3V3_SUS, SMC_PM_G2_EN, 3V3_S5.

    Comment


    • #3
      I just found another MBA charger, a Mag 2 albeit had come with another very dead MBA (with tea in it). However , that charger also does not give me any voltage at J7000.
      Since both my Mag 2 chargers are not giving me any voltage at P1 and P2 of J7000, I am using the Mag1, which came with the 2009/10 Macbook Pros.

      It fits as long as the board is not in the alu casing, and gives me 19V at P1 and P2 of J7000, and power as far as Q7010.
      For the purpose of testing I have no choice but to keep using it, I suppose:
      I tried with the other DC in board (of the tea damaged machine), but no changes as far as voltage on J7000 with Mag2 chargers I have here.
      So , measured with the Mag1 in place, all testpoint show 0V:

      F7140: 0V
      L7095: 0V
      SMC_RESET_L: Testpoint 804 and R7100 P1 : 0V R5100:0V
      SMC_ADAPTER_EN: Probe 595: 0V R5185:0V
      PM_BATLOW_L: Testpoint 639: 0V Q3000: 0V
      PM_SLP_SUS_L: Q5510: P2: 0V
      3V3_SUS: Not found on my boardview
      SMC_PM_G2_EN: Probe 778: 0V R5198: 0V
      3V3_S5: Not found on my boardview

      I might be able to lay hands on a proper Mag 2 in a few days or so: I have a call out to a friend. Other than that it still seems that nothing goes past Q7010....maybe the gate voltage is not right for it to pass the power?

      Comment


      • #4
        OK, plot thickens!! I just tried both Mag2 chargers on the other tea-damaged 820-00165-A ( I will call it board 'T') , and with both mags I do have 14.9V on the two relevant J7000 points. This means that the chargers must be OK after all, but somehow do not register on the original board I am trying to fix.....Does that give you any clue as to where to look? And maybe the board T might not be beyond hope either?

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        • #5
          The good upshot is that my tea damaged board can serve as a donor now. While completely corroded in some sections with caps green and falling off, the PPDCIN_works on that one , past Q7110 up to D7005. I am about to confirm the ohm measurements for the resisters pertaining to the mosfet Q7010, to see if one of them is messing with my gate voltage.

          Comment


          • #6
            Magsafe 1 charger, even using 1--->2 adapter, will generate weird issue on 2015 machines.
            There is a difference for the handshake protocol between MLB and charger.

            The board from first post has leakage on the input stage and original Magsafe 2 charger detects that and gets blocked.
            Common issue Q7180, or D7012.
            Post exact value (measured onboard, ohm scale) for R7180/81, R7185/86 and R7012.

            Comment


            • #7
              Cool, great learning curve, thanks so much
              R7180: 99.2 k
              R7181: 61.8 k
              R7185: 474 k
              R7186: 333 k
              R7012: OL

              I have R7012 on my donor board reading 68 k !!!
              Anything I should know to safely remove and install it on my good board?

              Comment


              • #8
                Just solder correct value R7012...

                Comment


                • #9
                  I hate to admit it, but I screwed this up. I just could not find a way to hold down that resister while soldering the ends, it kept sticking to my tools, just too tiny. Then I tried to use hot air, I did not get it to stick either, lots of flux, but no cigar..Finally one end of the resistor came off and it lost connectivity. Could you recommend a source to replace this resistor? And a means to attach it to the board? Sorry for the newbie questions, but one has to start somewhere...

                  Comment


                  • #10
                    You must put leaded solder on the board pads first, and use quality flux.
                    Then place the resistor and solder one pin.
                    Hot air will help to align if the flux is really good.
                    Get a good microscope, if you don't have one yet.

                    Search schematic of the scrap boards you have, for 68K resistor.
                    You can solder somehow even bigger size (0402); case you can pick it from normal laptop boards...

                    Comment


                    • #11
                      Thank you for your patience and for taking the time to spell it out for me. Very much appreciated. I have a good microscope,the flux is the brand Louis recommended, but the source was Ebay, which is according to him not good enough...Anyway,I will order the real flux from Amtec and will find another resistor, with those specs on a donor board ,or buy it somewhere...I was thinking I could solder some copper leads to the pads and place the resistor elsewhere on the board, so I will not jeopardize neighboring components with my shaky attempts at soldering in such in such tiny spaces....I let you know when/if I get somewhere. Cheers,J

                      Comment


                      • #12
                        One more question regarding that 68k resistor. How critical is it to get ALL the sub specs right, namely 1% 1/20W MF 201. I have a donor board ,an A1286, which has a 68K 5% 1/16W MF-LF 402 on it. Also have been looking on ebay where I can get carbon film resistors rates 68k 1W +-5% . Those have handy legs on them, for me to have something to hold on to when soldering to the pads and tuck out of the way after... Any thoughts on those options?

                        Comment


                        • #13
                          68K values is most important in this case.
                          Depending of that, original charger will recognize the board.
                          It will probably accept 62-75K, you can try that.
                          0201 is the size, but you can try to accomodate 0402.

                          I have a kit like this
                          https://www.ebay.es/itm/0201-SMD-SMT...zk3o:rk:1:pf:0
                          and is more easy to use than the book, for 0201 size.

                          I recommend you to get book style for 0402-0805.
                          https://www.ebay.es/itm/0201-0805-12...5qdQ:rk:1:pf:0
                          I recommend you buy only resistors, not resistors + caps version (useless cap values)...

                          Comment


                          • #14
                            So I found a 68k resistor here locally, not an SMD, but one with legs. I am improvising, to make up for my shaky hands and still limited soldering skills: I attached a copper wire to P1 pad of R7012 attached my new resistor and grounded it to a convenient ground in the hood. Made sure the wires are all insulated from other component. Now I do have 14.9V at J 7000!

                            I re-tested the points you asked me to check earlier, but all remains the same there
                            ??????F7140: 0V
                            L7095: 0V
                            SMC_RESET_L: Testpoint 804 and R7100 P1 : 0V R5100:0V
                            SMC_ADAPTER_EN: Probe 595: 0V R5185:0V
                            PM_BATLOW_L: Testpoint 639: 0V Q3000: 0V
                            PM_SLP_SUS_L: Q5510: P2: 0V
                            3V3_SUS: Not found on my boardview
                            SMC_PM_G2_EN: Probe 778: 0V R5198: 0V
                            3V3_S5: Not found on my boardview

                            I measured again at R7005 to see if mosfet Q7010 is now allowing voltage to come through, but there is nothing still...

                            Comment


                            • #15
                              Post Q7010 voltages, with original Magsafe 2 charger; considering you get 15V at J7000.

                              Comment

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