In case you are wondering most of them (probably >90%) dont know how those gadgets work either. They are taught procedures (there are whole repair technicians s

In case you are wondering most of them (probably >90%) dont know how those gadgets work either. They are taught procedures (there are whole repair technicians schools in China), not operation theory. For example they can diagnose which part on a laptop motherboard is broken by observing current draw/time when booting and looking up answer in the notes (notes made by real engineer or guessed/bruteforced by another tinkerer). This way unqualified worker can tell you in under 30 second what needs to be replaced on a phone/tablet/laptop PCB. Its like a human powered repair database lookup machine, they are all working from the script. You could say they are all Indian DELL phone support line :) Im not saying its bad, its just how it works.