OG Switch non-boot

Hi, guys. Newly stepping into Switch repair here. I have a Switch that will not boot. No charge indicator. I’ve already tested battery, and it works. Charge circuit capacitor continuity tests fine. Swapped working board into the frame and LCD works fine.

Currently have a usb voltage tester coming in to check if fast-charge is toggling, but otherwise, what should I be checking next?

Question #2; In the scenario that I just say F it and buy a new board, are HAC-CPU-10 & HAD-CPU-01 interchangeable?.

Really hoping for some help if anyone is able.

Check the charging port to make sure its good and if so plug in a charger with a battery connected to the board. If you can Use a original Nintendo charger and a usb tester that displays in 5v and 15v. What is the Voltage and amp being drawn?