Which of the following is not a good troubleshooting method?

The shotgun technique part replacement is not a good troubleshooting method because it involves randomly replacing parts without a clear understanding of the actual issue. This approach can lead to unnecessary expenditures, as it does not systematically identify the root cause of the problem. In troubleshooting, efficiency and targeted actions are essential, and replacing parts based on haphazard assumptions does not align with those principles.

In contrast, effective troubleshooting methods such as tracing the system from the compressor to the actuator or backtracking from the actuator to the compressor involve systematic analysis of the fluid power circuit. These methods allow for examining specific components and determining where failures may be occurring. Additionally, part replacement based on a maintenance history log can be a useful approach when there is a documented correlation between specific parts and failures, enabling repairs to be more focused and effective.