MacBook Pro A1990 No Power repairs (5V on PPDCIN)

https://resetlab.co.za In this video , we have a MacBook Pro 15 inches A1990 with power issues , as usual, because we plug into a charger on a No power device , we first define the state by using a multimeter, until then, we don’t connect charger, after taking out the back cover , we measured for a short to ground at PPBUS , but there was non, we then check at the NAND region for a short and non was found , then we connected our charger and was only getting 12.3V on our PPBUS instead of 12.6V, this further meant that we have 5V and PPDCIN instead of 20V, we narrowed down the cause to UB300, through a short at its PP3V3_UPC_TA_LDO line , thereafter, we made replacements, thus the repair was complete.