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820-00045 a1534 wont turn on at all, not water damaged

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  • 820-00045 a1534 wont turn on at all, not water damaged

    What are the troubleshooting steps for this one if it wont power on?

    I took out the board, checked under scope, literally no water anywhere, no dents on the housing, so it seems laptop was properly used.

    The small white LED is on when i connect the charger (i have an original apple charger usb-c), i can measure 8V on the battery connector when they are connected.

    Fixed this model few times with new keyboard and new screen, but never measured the board before.

    So what measurement will i report to you?

  • ielectron
    replied
    U7400 replaced no changes after this too looks like PCH is faulty I'd say

    Leave a comment:


  • ielectron
    replied
    I will try swap from donor board U 7400

    Leave a comment:


  • 2informaticos
    replied
    There should be PCH/CPU, or U7400 problem...

    Leave a comment:


  • ielectron
    replied
    PCH heated up no changes, I checked those
    PM_PWRBTN_L
    3V3_S5
    no changes on those lines after heating up too

    Leave a comment:


  • 2informaticos
    replied
    Put good flux and heat PCH untill 180-200 degrees; just to burn eventualy crap...

    Leave a comment:


  • ielectron
    replied
    yes PM_PWRBTN_L have no changes I checked once more
    AVREF_SMC = 3v

    Leave a comment:


  • 2informaticos
    replied
    Still 1.22V at PM_PWRBTN_L?
    Looks like PCH issue; it should have a weak pull-up resistor inside.

    Do you get AVREF_SMC voltage?

    Leave a comment:


  • ielectron
    replied
    resistor removed still no changes on PM_PWRBTN_L
    3V3_S5 is still on 0.5v level no changes

    Leave a comment:


  • 2informaticos
    replied
    "PM_PWRBTN_L = 1.22v"
    It has strong pull up resistor (1K) to 3V3_S5.
    Remove R1405 and check its level again.

    Leave a comment:


  • ielectron
    replied
    resistance on L7560 455 ohm
    double checked PM_SLP_S5_L = 0V
    I checked on TP first but looks like board view is a bit different than the actual main board and test point wasn't for this signal

    Leave a comment:


  • 2informaticos
    replied
    "3V3_S5 = 0.5v
    -------------
    PM_SLP_S5_L = 3v3"
    Are you sure?
    High level for PM_SLP_S5_L means the board already achieved S5 state and goes to S4; but you are missing a basic S5 voltage!
    Check resistance to ground at L7560.
    You could have a problem with U7400.

    Leave a comment:


  • ielectron
    replied
    I check voltages that you said

    3V3_S5 = 0.5v no pulses

    PM_SLP_SUS_L 0 = 0v no pules

    PM_SLP_S5_L = 3v3 no pulses

    PM_RSMRST_L = 0 no pulses

    SMC_ONOFF_L = 3v26 going down to 0.3v when power button pressed

    PM_PWRBTN_L = 1.22v no changes when pressing power button

    Last edited by ielectron; 02-12-2019, 05:18 AM.

    Leave a comment:


  • 2informaticos
    replied
    Post 3V3_S5, PM_SLP_SUS_L, 3V3_SUS, PM_SLP_S5_L, PCH_RSMRST_L.
    Check if any pulse at least.

    Trigger SMC_ONOFF_L and see if PM_PWRBTN_L reacts.

    Leave a comment:


  • ielectron
    replied
    I put back U7100 from donor board PPBUS_G3H is back to normal 8.6V
    laptop still doesn't turn on.
    PP5V_S0 =0V
    PP5v1_s4w = 0V
    P5VOUT_EN = 0V
    PP3V3_G3H present
    I reflow SMC but no changes.

    Leave a comment:

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