This customer sent in their MacBook Pro to our store in New York City for our logic board repair service because the machine would not turn on.
What was causing the issue?
We start off diagnosing this machine by looking at the power rails that need to be present for the machine to turn on. We find that we are missing PP5V_S5. This is created by U7200. After checking the datasheet for U7200, we find that the enable line is not present for U7200, so that chip is probably not the issue. We follow the rail back to find that the SMC is not creating the rail necessary to turn on U7200. After checking to ensure the SMC is getting power, we determine that the SMC is bad.
How do we fix the issue?
We start off by finding a donor board with the same model SMC and programming. Then, we remove the chip from the donor and reball it. We clean up the pads from the old SMC on the problem board and solder our donor SMC to the board.