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A2179 820-01958 5v 0.345a Cycling

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    #1

    A2179 820-01958 5v 0.345a Cycling

    Good Afternoon

    I'm working on an A2179 thats taking 5v and 0.345a from the charger with the board removed.
    Both ports are cycling and seem to only work on one side. The side that works is different for each port. - I hope that makes sense.
    I'm not sure if this has to do with the board or the ports.

    I replaced both CD3217 chips months ago and set the board aside when they didn't fix the issue.

    U3060 gets hot on the thermal cam and heat cycles with the charger. I checked all pins on U3060 in continuity mode and nothing was short. (I did not check in diode or resistance mode)

    PPBUS_G3H: 3.3v Cycling

    Any advice would be appreciated. Thank you.
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    #2
    Was U3060 ever removed / reflowed / toyed with? Perhaps soldered in the wrong orientation (ie. upside down)?

    U3060 is the TBT flash rom storage device that contains the firmware used by the PD controllers (ACE CD3217). Respectively, this component is powered by the CD3217 @ U3100 through the PP3V3_UPC_X_LDO low current rail.

    Carefully measure the voltage to ground of PP3V3_UPC_X_LDO. This rail should be a stable value of 3v3 on a normal box.

    Comment

      #3
      U3060 was never removed or messed with.

      The voltage to ground of PP3V3_UPC_X_LDO is 3.2v with the front port powered and 3.4v with the back port powered. But power cycles when the USBC amp meter cycles.
      I also noticed the front port cycles quickly (Every 1-2 seconds) The back port cycles every 10 seconds.

      Thank you for your help

      Comment

        #4
        Remain testing with the front port at this time. With no power, meter in resistance mode, confirm that each resistor to this spi flash device is ok and present. You can also test with checking the voltage to ground of each pin on this flash rom device. Attempts are being made (every 2 seconds) to boot the firmware from this device.

        Could the thermal signature be from the other side of this pcb area?

        The power ldo should be at 3v3 but not 3v4 as reported by other port.

        Be sure to check the resistance to ground of every onboard inductor to confirm there is no shorting part on a rail. The heat from this flash rom area is still of concern. Any liquid damage? What is the history of this board?

        Comment

          #5
          U3060 Voltages to ground:
          Pin 1: 3.2v
          Pin 2: 3.2v
          Pin 3: 0v
          Pin 4: 0v (Ground)
          Pin 5: 1.38v
          Pin 6: 0v
          Pin 7: 3.2v
          Pin 8: 3.2v

          The thermal signature is definitely from U3060

          Inductor resistances:
          L8100: 464 ohms
          L8400: 182 k ohms
          L7400: 370 ohms
          L7230: 118 ohms
          L7220: 118 ohms
          L7210: 118 ohms
          L7030: 180 k ohms
          L7690: 29 k ohms
          L7670: 21 k ohms
          L9060: 21 k ohms

          There was no liquid damage to the board. Everything looked very clean. Originally took 5v and I had diagnosed a CD3217 issue. (I may have been wrong) I replaced both CD3217 chips months ago and put the board away when it didn't solve the problem.

          Comment

            #6
            Remove all power. Meter in DIODE mode.

            Red meter probe, yes red to ground.

            Black meter probe on pin # 6 (TBT_XT_SPI_CLK) on U3060.
            Black meter probe on pin # 5 (TBT_XT_SPI_MOSI) on U3060.

            What are the measurements?

            Comment

              #7
              U3060 Diode mode measurements:
              Pin # 6 (TBT_XT_SPI_CLK): 0.554
              Pin # 5 (TBT_XT_SPI_MOSI): 0.569

              Comment

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