Question

you work in the computer - repair department of a large retail outlet. a customer comes in with a workstation that randomly shuts down. you suspect that the power supply is failing.
what should you do first to troubleshoot the issue?
use a known - good spare to swap with the existing power supply.
use a multimeter to test the power supplys electrical properties.
use a cable tester to check the power supplys connections.
use a power supply tester on the power supply.

Explanation:

To troubleshoot a malfunctioning power - supply, the first step is to test its electrical properties. A multimeter can be used to measure voltage, current, and resistance to determine if the power - supply is functioning properly. Using a known - good spare is not the first step as it doesn't diagnose the problem with the existing power - supply. A cable tester checks cables, not power - supplies directly. A power - supply tester is also a valid tool but testing electrical properties with a multimeter is a more fundamental first step.

Answer:

Use a multimeter to test the power supply's electrical properties.