@TechConnectify years ago (eh late 1990’s) I worked for a Sun reseller and as part of getting certified for Sun’s bigger servers I had to take a series of Sun trainings including a week long course on troubleshooting. It was really excellent - covered a lot of pretty universal techniques (along with some specific to Sun - like how to get root if you have physical access)

For the final day/test we had a room of machines to troubleshoot. One was “sticky tape on a connector”

Another “OS rooted”