Locate the circuit in your home circuit breaker for the kitchen breakers and shut them off. Verify the microwave power is off by looking at the digital display that should be off. Wait a few minutes to ensure the bulb is cool.
Remove the one side screw from the plastic bulb cover on the center underside of the microwave. Slowly lower the cover panel until it hangs loosely and the bulb is visible.
Grasp the bulb by its base and gently pull it out of the socket. Replace with a 130 volt 50W halogen bulb for surface light. Lift the cover back into place and reattach the screw.
Turn the power back on when finished.
Turn the circuit breaker switches for the kitchen and microwave to the off position and verify the power to microwave is cut off. Wait for the bulb to cool.
Locate and remove the two screws holding the front top plastic grill in place. Remove the grill. Slide the filter to the left and remove. Note that the filter is optional so you may not have one.
Unscrew and remove the one screw holding the bulb shield. Pull the shield out.
Grasp the bulb at its base and pull it out of the socket. Replace with a 120-130 volt 20W halogen bulb into the socket.
Replace the bulb shield and holding screw. Slide the filter back into place. Snap the grille cover back into place and the two holding screws. Turn the power back on.