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MacBook Air a1370 only runs on the charger

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  • crea2k
    replied
    Iv got a feeling this could be the customers crappy battery causing half of this. I know the dc in board looked like garbage as it was water damaged and had components missing. So that was replaced and the voltage appears to be getting through ok now. Iv ruled the isl chip out as changed that. Iv just checked the customers battery and it's zero volts at the terminals. If I measure the cell tabs it's 1.9v so it looks like the bms under voltage protection has kicked in. I tried charging it by dtps and it wasn't having any of it, which explains why it was saying to replace the battery as the bms was probably telling the motherboard the battery was below minimum cell voltage (usually 3 volts on a lithium battery).
    So have ordered another in, so will see how that goes.

    Leave a comment:


  • crea2k
    replied
    Here are some voltages from around ISL6250 :

    PP3V42_G3H
    3.39v

    CHGR_CSI_P
    14.50v

    CHGR_CSI_N
    14.45v

    CHGR_BOOT
    12.89v

    CHGR_UGATE
    10.95

    PP5V1_CHGR_VDDP
    5.05v

    CHGR_CSO_N
    8.36v

    CHGR_CSO_P
    8.36v

    SMC_BC_ACOK
    2.97v

    CHGR_RST_L
    3.3v

    CHGR_VNEG_R
    1.3v

    CHGR_VCOMP_R
    1.3v

    CHGR_DCIN
    14.2v

    CHGR_ACIN
    3.74v

    CHGR_ICOMP
    1.54v

    CHGR_CELL
    0v

    CHGR_VCOMP
    1.52v

    CHGR_VCOMP_R
    1.44v

    tested :
    R5420 = good
    R7085 = 0.469M
    R7080 = good
    R7081 = good
    R7005 = good

    Voltage @ R7005 = 14.1v & 14.35v
    Voltage @ R7080 = 14.69v & 5.57v
    Voltage @ R7001 = 5.1v & 5.05v
    Voltage @ R7085 = 14.62v & 5.7v
    Voltage @ R5420 = 0.061v & 0.061v




    Last edited by crea2k; 02-05-2018, 07:21 PM.

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  • crea2k
    replied
    So im testing PPDCIN_S5_CHGR on Q7080 and am getting 14.5 volts but it should be 18.5v according to the schematic. If I measure resistance to ground on that line I get 040.0kohm , but without another board to compare to that is meaningless, all we know what is happening so far is the voltage isnt what it should be on that line, so il see if I can find any filters or something on that line. Iv tried two charger and two dc in boards and get that same 14.5-14.8volts at the dc in board connector.
    Last edited by crea2k; 02-05-2018, 04:09 PM.

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  • crea2k
    replied
    Right using google images im guessing its a
    MacBook Air 11" (Mid 2011) 820-3024

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  • crea2k
    replied

    Leave a comment:


  • crea2k
    replied
    Well I changed the ISL6259, but still the same problem, im trying to find some kind of schematic for it, but with macs it seems to be about 1000X harder to actually identify what you actually have in front of you as they call them all the same thing.

    Leave a comment:


  • crea2k
    replied
    Ah cool ok thanks, il see if I can find out which ic this is. Reading the schematics is simple enough it's that stupid board view software that drives me round the bend. Why the layout can't just be on the same PDF I don't know.

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  • Jessa_the_Professa
    replied
    On the MacBook Pro, there is a tristar-like chip that senses the dc in charger, produces the 'ac ok' signal that allows the charger voltage to enter the device, communicates with the smc to initiate charging, and then generate the main power voltage to turn the whole machine on, monitor the dc and battery voltages and actually do the action of charging. This system is on a couple of pages of schematics and is the most common failure point for macbooks for both water damage and electrical damage. Louis probably has 20-30 videos on a wide variety of faults within this system--which are largely "the charging chip is bad" "dudes or traces surrounding the charging chip are bad" or "the SMC itself is bad" He walks through this circuit in any video with the work 'charging' or 'sys onewire' and that is a great resource if you haven't worked on macbooks but have a good general understanding of schematics. I believe the MacBook Air will be different from the standard macBook Pro charging system, but likely very similar.

    The DC in board you changed is just that---a plug to convey DC input to the board.

    Leave a comment:


  • crea2k
    commented on 's reply
    It's definitely the logic board as the customer tried 2 different batteries, Iv tried two different chargers and dc in boards. We just don't know what on the motherboard is bad as other than the backlight circuit I know Jack when it comes to fixing macs.

  • crea2k
    replied
    Is the charging chip on the dc in board or is that seperate ?, iv changed the dc in board itself.

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  • Jessa_the_Professa
    replied
    What does the charging chip area look like? Was there water there? I haven’t fixed any air charging problems, but for MacBook Pro it is just a couple of pages of schematics. When I troubleshoot MacBook Pro charging, I check for output of the charging chip—smc_bc_acok and if that isn’t present troubleshoot why. The charging chip area has some battery current sensing resistors and I would expect that Louis has videos dedicated to this exact problem with a method to differentiate charging chip problems from battery data line problems from SMC failures.

    Leave a comment:


  • eDigitCom
    replied
    an know good logic board if you could get one would really narrow the fault done. not much more to try i think

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  • crea2k
    replied
    Yes the mag safe was replaced, the smc resets when the battery is removed.

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  • eDigitCom
    replied
    You could be done to the logic board itself??

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  • eDigitCom
    replied
    Was the Mag-Safe control board replaced

    Was the SMC Reset (system management Controller)??

    Leave a comment:

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