Pull the Magic Chef's power plug from the wall or switch off the power at the circuit breaker. Power up the microwave to test the circuit. If it does not power up, it is safe to proceed. If power is still connected, switch other breakers until you find the correct one.
Unscrew the screws located at the corners of the microwave's grate or grill. Locate a small plastic panel; this is the light bulb panel.
Remove the screw on the plastic panel using the screwdriver. Slide the panel out of the way, setting it to the side if it comes loose.
Unscrew the bulb gently and add a fresh 30-watt bulb. Replace the light cover, screwing it back into place.
Reattach the grill, putting in the screws to hold the grill grate in place. Plug in the Magic Chef’s power socket or turn on the breaker. Place a cup of water inside the microwave and heat it for a few seconds to test the bulb.