Corrosion of the SMC solder connections.

SMC not working(if SMC is off, you will have 12.23 V on PPBUS_G3H instead of 12.56 V) because it is dead, not turning on (SMC_RESET_L low).Įxample: (U5110 (chip responsible for SMC_RESET_L) not working).

16–20 V on ADAPTER_SENSE means charger voltage is leaking into ADAPTER_SENSE, below 2 V means it is missing usually due to a bad DC in board.

ADAPTER_SENSE not 3 V due to bad DC in board.

Unplug it, see if it works (short on 3.3 V or 5 V rail on the I/O board can cause this problem).Įxample: (replaced U1950, capacitor and resistor) Sometimes shotgun replacement of the chip is a clean solution.

PM_SLP_S4_L missing for random reason, thoroughly inspect clock chip, tiny specks of corrosion next to it can kill it.

U7100 area and Thunderbolt T29 Boost Regular cleared, corrosion removed and replaced. Major corrosion around U7100 (ISL6259) area.

U7100 ISL6259 bad, shorted current sense resistors R7121 and R7122 to ground through the U7100. No power, PPBUS_G3H 4 V instead of 12.56 V Ribbon connector to keyboard bend/dirty/broken (bend back/clean/replace)Įxample: (second repair, ribbon connector bend/dirty)

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