To check for a faulty power supply, what can be tested?

Testing the voltage output is crucial when checking for a faulty power supply because it directly indicates whether the power supply is functioning correctly. A power supply is designed to convert AC power from the wall outlet into DC power at specific voltages necessary for the computer's components to operate. If the voltage output is outside the manufacturer's specifications, the power supply may either be failing or not supplying adequate power, leading to system instability or complete failure to boot.

Ensuring the voltage output is within the acceptable range allows technicians to diagnose issues related to power delivery accurately. This step helps in isolating the problem to the power supply rather than other components, guiding further troubleshooting efforts more effectively.