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820-2850 not turning on

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  • #16
    No nothing happens.

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    • #17
      Well, that indicates a communication issue with the SMC. Check the data bus from SMC to battery on diode mode. But in your first measurements you say PPBUS @12.56V so SMC must be working. Disconnect battery indicator and try charging again.

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      • #18
        I checked r5280 and r5281 in diode mode with no charger plugged in and this is what I got. The readings were the same for both resistors
        Pin 1 - -OL
        Pin 2 - -0.97v (Its showing what looks to be a negative number. Didnt know that was possible and the multimeter beeps the entire time I have the probe on pin 2)

        In resistance mode both showed over 2kohms when the schematic says it should be 1kohms

        The area around the ISL6259 looks clean with no liquid damage.

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        • #19
          Measurements do not make sense. No idea what you are doing here....Red probe to GND black to the data bus, multimeter on diode mode. No power and battery of course!

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          • #20
            When you say the data bus are you referring to the 2 resistors R5280 and R5281 correct?

            I had the battery plugged in which was probably causing those bad readings. I removed the battery and measured in diode mode with red probe on ground.
            Pin 1 - 0.38v
            Pin 2 - 0.503v
            The measurements were the same for both resistors.

            Also, In resistance mode they are both measuring 2kohms.

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            • #21
              .503 seems ok.
              Measure PPBUS again and see if it is at 12.3 or 12.56V

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              • #22
                Okay with only charger plugged in PPBUS_G3H pulses and is not stable from anywhere around 3v- 12v
                With the battery plugged in and charger plugged in it pulses from around 12.1v to 12.5v
                With the battery only it is at a stable 12.1v.

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                • #23
                  I suspect a short, check all coils for shorts. You can remove F7040/41 and see if PPBUS is stable then.

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                  • #24
                    When you say check all coils for shorts which coils are you referring to?

                    The fuse 0v in diode mode so I believe it is fine. L7030 did not measure as a short.

                    I removed F7040 and checked ppbus_g3h again and this is what I got.
                    Pin 1 - still pulses from 12.57 not stable.
                    Pin 2(PPBUS_G3H) - 0.56v and slowly goes down.

                    (Measurements with F7040 removed from the board)
                    I went and checked the current sensing on u7000 they all measured fine. I got 5v on VDD but on Pin 3(ACIN) I was getting 0v.
                    D7005 is pulsing between 16.3v - 16.83v. Pin 1 of R7010 also had the 16v but Pin 2 shows 0v.
                    In resistance mode R7010 measured 30kohms but r7011 measured only 2ohms.


                    While taking those measurements I noticed the charger light is now dim green and doesn't turn bright green anymore when I plug the charger. Tested with another Dcin board and same issue.
                    PP3v42_G3H is 3.41 while SMC_BC_ACOK is 0v.
                    Last edited by ytesfay80; 10-07-2016, 12:06 PM.

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                    • #25
                      I don't know what you are doing but now it seems you killed the 6259.....
                      Also according to the diagram there are 2 fuses 7040 and 7041, no idea if they are on the board too.

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                      • #26
                        There is no f7041 on the board.
                        I put F7040 back on the board and replaced the isl6259 and the green light came back on and SMC_BC_ACOK is 3.1v and CHGR_ACIN is back at 3.9v
                        PPBUS_G3H is still at only giving me around 1.08v

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                        • #27
                          Well, remove F7040 and check again. This time don't kill the 6259...
                          If it still is not stable at 12.xx volts then check the sense resistors and traces.

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                          • #28
                            Some more crap happened. I removed F7040 and measured Pin 1 of F7040 and it was stable around 6v. Pin 2 had around 0.3v. I unplugged the charger and plugged in back in about 10 seconds later and now I have no light on the charger at all. I didn't take any measurements other than on the pads of F7040 so I don't think I killed anything.
                            F6905 is pulsing and only goes up to 0.23v.

                            I measured the current sensing on U7000. Pins 27/28 - 20.5ohms Pins 17/18 - 3.1ohms
                            The traces are good when I measured in continuity mode.

                            I've tried putting F7040 back on but still no change and I tested with another Dc-in board and the same thing happens.

                            Is this issue worth continuing to troubleshoot it?

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                            • #29
                              Did the charger trip? Test on other macbook or unplug for a few minutes.

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                              • #30
                                I don't think its the charger. I plugged the charger into my 2011 MBA and the light came on the charger and it was working.
                                Its not the Dc-in board because I plugged the same one into a 2012 MBP and it had a light on the charger.

                                When I plug it back into the 820-2850 there is no light on the charger at all.
                                Last edited by ytesfay80; 10-08-2016, 02:04 PM.

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