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Macbook Pro 820-3115-B Green Light But No Turn On

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    Macbook Pro 820-3115-B Green Light But No Turn On

    I consider myself a beginner, with some experience in Macbook motherboard repair. I have some difficult finding the problem of this Macbook Pro of 2012.

    The motherboard didn't suffer liquid damage and it's physically clean.

    BUT I see a little blink in the GREEN LIGHT.

    beginner question… Can it mean short circuit? Or does that blink could mean another problem?

    Motherboard story:

    I comes to me because it doesn't start for a (non-original) charger. I repaired the original charger and gives me the green light but it doesn't turn on.

    I take the Voltage:

    PP3V42_G3H = 3.42 v
    PPBUS_G3H = 0.7 V

    I do not continue reading because “according to understanding”· all the voltage are generated of PPBUS_G3H.

    Diodo Mode readings
    PPBUS_G3H 452
    PP3V42_G3H 361
    PPVRTC_G3 448
    PP5V_S5 518
    PP5V_SUS 425
    PP5V_S3 149
    PP5V_S0 410
    PP5V_S0_HDD
    PP3V3_S5 142
    PP3V3_SUS 352
    PP3V3_S4 385
    PP3V3_S3 350
    PP3V3_S0 349
    PP1V8_S0 204
    PP1V5_S3_DDR 152
    PP1V5_S3 152
    PP1V5_S3RS0 167
    PP1V5_S0 339
    PPVTTDDR_S3 478
    PP0V75_S0_DDRVTT 447
    PPVCCSA_S0_CPU 12
    PP1V05_SUS 492
    PP1V05_S0 12
    PP3V3_ENET 369
    PP3V3_FW_FWPHY 433
    PP1V05_S0_PCH_VCCADPLL 153
    PPVCORE_S0_CPU 4
    PP1V5_S3_CPU_VCCDQ 163


    Since I found rare readings on PP5V_S3 = 149, and on other motherboards I have a reference from 434 to 446, I replaced Q7261 for a new one. Measurements improved. Change from 149 to 442.

    He took out the F7040 fuse. To isolate the Source of 12v (U7000)

    F7040 readings diode mode:

    pin 1 = 497
    pin 2 = 465


    Diodo Mode readings U7000

    Pin Read
    1 653
    2 627
    3 540
    4 538
    5 730
    6 719
    7 728
    8 543
    9 723
    10 533
    11 535
    12 360
    13 503
    14 498
    15 729
    16 670
    17 454
    18 455
    19 463
    20 465
    21 465
    22 Ground
    23 453
    24 921
    25 589
    26 650
    27 644
    28 628


    Please heeeelp m

    #2
    Re: Macbook Pro 820-3115-B Green Light But No Turn On

    Watch some Louis Rossmann videos, everything is explained and I bet there are several videos about a similar issue on this exact board.
    Check voltage on ACIN/DCIN/VCC/VCCP/CSIN of U7000. Measure resistance between pins 17/18 and between pins 27/28 of U7000.
    OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

    Comment


      #3
      Re: Macbook Pro 820-3115-B Green Light But No Turn On

      Everything was fixed installing a new U7000.

      Comment


        #4
        Re: Macbook Pro 820-3115-B Green Light But No Turn On

        Thanks for the advice

        Comment

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