Hi Sheldon,
[https://www.youtube.com/watch?v=qcWowCgOFOw|This link] shows the input unit of a laptop motherboard (DC jacket, capacitor, etc.). It might help you to localize where the power IC is on your motherboard.
There might be a diagram available for your laptop [http://www.s-manuals.com/motherboard/asus_x550la|here]. However, you also need to have the program to view the file.
I hope this helps.
Steffen