In this case study, we have a MacBook Pro 16" Retina 2019 A2141 model (board number 820-01700) which arrived in completely dead, with known liquid damage (tea spillage).
The first thing we do in cases with liquid damage, is disassemble the MacBook and ultrasonic clean the logic board. Before doing this, we take images of all areas of the logic board; we don't want to lose these visual clues! In the case with this logic board, there was damage in multiple areas; the U9080 area (which is highly prone to sending 13V to the 2.5V SSD voltage line, killing the NAND chips), the Touch ID connector, CD3217B12 chips for the two left hand USB C ports, and the angle lid sensor connector.
After the ultrasonic clean, we firstly reballed U9080; on these models, the 15" 2018-2019 models, and the newer devices, these are in an area very susceptible to liquid damage on the edge of the board, and if there is untreated damage underneath this, it has a chance of damaging the NAND chips in future (losing all data). After reballing U9080, when connecting a USB C ammeter, the MacBook is only pulling 5V from the charger when 20V is required for boot. We traced this to one of the damaged CD3217B12 USB C ICs, which was damaged by the liquid and shorting the LDO line to ground; the chip was getting extremely hot! After replacing this, the MacBook was pulling the correct 20V for boot, but it still wasn't booting up.
Upon disconnecting the angle lid sensor cable, the MacBook is booting up (albeit without detecting when the lid is closed), and we can see corrosion to this sensor along with damage to the connector (the pin for PP3V3_G3H_RTC_X is loose and the solder pad is destroyed). We replace the connector to resolve this, and solder a wire to the pin which had the destroyed pad, connecting it to the probe point for PP3V3_G3H_RTC_X on the back of the logic board.
After replacing the angle lid sensor with a new one (pulled from one of our donor A2141 models, since the new ones ordered were not programmed/calibrated to work), the MacBook is fully working!
If your MacBook Pro 16" A2141 is not turning on and has suffered from a liquid spillage, we can help with this. Feel free to book it for our free liquid recovery service and we can find out what is causing the issue, and offer the relevant repair.
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