What is a critical first troubleshooting step when dealing with electric-powered machines?

Turning off electric power is a fundamental first step in troubleshooting electric-powered machines because it prioritizes safety. Ensuring that all electrical sources are disconnected prevents accidental shocks, short circuits, or further damage to the equipment while you investigate the issue. This step is particularly crucial before inspecting or repairing any components to protect both the technician and the machine itself.

The other choices, while they may be relevant at other points in the troubleshooting process, could introduce risks or complicate the situation if the power is not turned off first. Allowing the system to operate could lead to injury or exacerbate the existing problem. Measuring actuator output or checking fluid levels might be necessary in the troubleshooting sequence, but doing so without first ensuring the equipment is powered down can be dangerous. Prioritizing electrical safety is essential when working with any machinery that operates on electricity.