Using a multimeter, check pin 5 (VIN) of PU8 for 19V. Check pin 3 (EN) for 3.3V. If EN is missing, the EC is not booting, pointing to a BIOS or EC firmware issue.
The RT8223P requires an EN (enable) signal from the EC. The schematic shows that EN comes from pin 87 of the IT8987 (EC). Without the schematic, you would never know this pin exists. ms-16j91 schematic
Once you obtain the MS-16J91 schematic, store it offline. Many repair websites expire or get shut down. Keep a copy on your hard drive and a backup in the cloud. Then, pay it forward – share it with the next technician who posts “Help – no power on MS-16J91.” Disclaimer: Schematics are for educational and professional repair purposes only. Circumventing security or modifying hardware may void warranties and violate local laws. Always follow ESD safety precautions. Using a multimeter, check pin 5 (VIN) of PU8 for 19V
Open the PDF and search for “+3.3V_ALW” (always-on 3.3V). You’ll find that this rail comes from a voltage regulator (e.g., PU8 – RT8223P). The RT8223P requires an EN (enable) signal from the EC
While finding a legitimate copy requires effort (forum searches, trusted communities), the investment pays off instantly. Pair it with a boardview file, a good multimeter, and patience, and you can resurrect even the most hopeless MSI GE62 or GP62 laptop.