Experts rightfully advise solving for failure causes. But there are some problems if you expect repair techs to do this:
• Techs are often in a high-pressure fire-drill mode, going from repair to repair. No time.
• Techs may lack the necessary skills (this is a specialized area of knowledge) or the information needed to correctly identify the likely cause.
• Adequate failure analysis may not be possible with the information available from one repair. It may require meta data or at least information from multiple pieces of equipment.
• The real problem may be hiding behind test data that have not been taken or system variables that have not been monitored.
The reality is the repair tech is typically making an educated guess about the failure cause, using limited information in a limited time to arrive at a conclusion that may not even be acted upon. It’s better to have the tech identify the failure mode (what happened) rather than guess at what caused it. Someone with the proper training in failure analysis (and the time to apply it) can then determine the likely cause.