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I have a 820-2879 with no power to one USB port. No water damage, I measured PP5V_S3_RTUSB_B_ILIM at pin 6 of Q4690 and I get .070 and pin 7 measures 5.0V. I replaced Q4690 and same thing. I also have 3.3 at both enable pins on Q4690. Any ideas???
Pin 4 is ok cause it is ground, but pin 1 is shorted, you can remove L4615 and see in which pin is the short, if is on pin1 problem could be C4615, C4616, C4617 or Q4690 again, if the short is on pin 2 the problem is D4610.