Turn off the device and unplug it from the wall
Inspect the power cord, plug, and connector for damage
Check the outlet with another device or outlet tester
Use a multimeter to verify the outlet voltage
Reconnect the power supply and turn the device on
Measure the power supply output voltage with a multimeter
Compare the measured voltage to the rated output on the label
Test under load if possible to confirm stable output
Check for abnormal heat, noise, or burning smell
Replace the power supply if voltage is missing, unstable, or out of range