Question HP 8470p power

Aug 25, 2023
I have several HP 8470p laptops 2 of them with upgraded quad-core processors, Intel i7-3630QM 3632QM these plug right in no problem.
The other day it wouldn't start, and I found that the charger / power supply had gone dead. But with a new one it still wouldn't start up. Just nothing, no reaction at all.
I suspect that whatever circuit in the laptop itself receives the 20V from the charger has been cooked, maybe when the charger expired it did so sending a jolt down the wire into the laptop.
Any ideas how to check/fix this?