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[SOLVED]820-3437 ISL6259 CHGR_UGATE, CHGR_LGATE not driving switching MOSFET(s)

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  • [SOLVED]820-3437 ISL6259 CHGR_UGATE, CHGR_LGATE not driving switching MOSFET(s)

    820-3437 No power on.
    Green / Orange light.

    Voltages around ISL6259:
    PPBUS_G3H (CHGR_PHASE pin 23) = 3.8V
    CHGR_UGATE pin 24 ~ 4V
    CHGR_LGATE pin 21 = 24mV
    CHGR_ACIN pin 3 ~ 5V

    Already tried changing Q1730 with no change.
    My Googling skills seem to be lacking somewhat. Can't find any datasheet on the ISL6259 so I will start measuring all values around the IC.


    Would someone clue me in on what I should be checking for please?
    Last edited by G.Beard; 08-20-2016, 11:43 AM.

  • #2
    Provide resistance of R7105, resistance between pins 17/18 of U7100, resistance between pins 27/28 of U7100, voltage at pin 19 of U7100, voltage at pin 20 of U7100.

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    • #3
      Originally posted by larossmann View Post
      Provide resistance of R7105, resistance between pins 17/18 of U7100, resistance between pins 27/28 of U7100, voltage at pin 19 of U7100, voltage at pin 20 of U7100.
      This is a board already worked on by lord knows who.

      Measurements
      R7105 to DCIN was 200ohms (so replaced with 20ohms). R7105 = 20ohms.
      This is power to the chip through series resistor maybe?

      Pin 17 to 18 = 3.5ohms

      pin 27 to 28 = Xkohms EDIT: it was 2k (replaced R7121 & R7122 with 10ohm). Pin 27 to 28 now 20ohms
      I'm guessing that these are coming off the current sensing resistor to a differential amplifier or comparitor on the 6259?

      Voltage at pin 20 = 5V

      Additionaly

      Just checked gate volatges again after replacing resitors with correct values. Pin 24 = 8.6V and pin 21 = 0.5V
      PPBUS_G3H = 8.6V...... But err, no turn on.

      Thank you, I'll keep digging into this board. The soldering was done rather well by whoever fucked this board with the wrong values in all the wrong places. This is kinda shitty as I can't see just by looking, what has been done.

      Thanks again, I'll be posting again soon I expect
      Last edited by G.Beard; 08-20-2016, 02:29 PM.

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      • #4
        Thanks to louis for the youtube and thanks to everyone giving thier time and knowladge.

        Boards a worker. There were no S0 enables so I injected S0 enable 3.3v but still no S0 rails turning on. Turns out the fault was U1900 had been soldered to the board incorrectly!
        All of these boards are from a company that buys from a company the "refurbishes" damaged Macbooks and laptops. This is not a small company so it begs the question of who are they employing to fuck shit up even further... 80% of the boards have been ruined by a moron and after 3 months of board repairs I am fixing 90% of what they can't, plus undoing thier stupidity. What's up with that.

        Again, thank you
        Last edited by G.Beard; 08-20-2016, 09:55 PM.

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