Same issue. Wasn’t the power cord because I tested with a known working one and my xbox still would not turn on. Disassembled my Xbox one. Found an IC , capacitor and a plug for the touch sensor had a lot of corrosion on the contacts. Cleaned these three points of corrosion and gave the entire PCB a good rub down (top and bottom side) with isopropyl alcohol. Put everything back together and Voilà.