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 by seeing that there is no green light on the charger. Next, we measure the power rails that are necessary for a green light on the charger, starting out with PP3V42_G3H. This rail gives us 0.00V. Next, we measure voltage drop to ground on PP3V42, which is 0V. This means we have a short to ground on PP3V42. Next, we remove the inductor for PP3V42 to see which side of the board the short is on. After measuring both sides, we find a short on the system side of PP3V42.
How do we fix the issue?
To find the short, we solder a wire to PP3V42 and connect it to our DC power supply. After we turn on the DC power supply, our short goes away. This means that the short was most likely in a capacitor somewhere on PP3V42 that was blown out by the voltage from the power supply. After plugging the board into the charger again, we see that we now have a working machine. This machine will undergo extensive testing after this to ensure there are no other issues, but it looks to be fixed now!