Hi community i am trying to trouble shooting a samsung a51 it wont charge or turn on im useing dock flex tester not sure if im using it correctly or even know what to do with the values. im still learning and trying to understand how phones work. i got the schematics, I cant find any information on the internet on how to use these dock flex connectors it looks like people are only selling them. in my search i found out the iphone uses tristar i wondering what the andriod version is. these question are probaly very noobish but i need to start someone to understand how the phones work and troubleshoot. i have basic understanding of electronics i purchased a course on udemy to learn about mobile phones micro soldering ect but the explanations are very vague and wish to learn more about mobile phones. If someone could please point me in the wright direction to have a better understanding that would be greatly preciated. thanks