If the light bulb is difficult to access due to the position of the bulb within the microwave (closer to the magnetron) remember to ensure the unit was not knocked on the side when replacing the outer cover of the microwave. I noticed a slight rattle from my microwave bulb after fixing it a few weeks back. Upon further inspection, the vent cover baffle was not properly covered with the vent cover. Nothing too dangerous but annoying. Also be sure to wipe the new light bulb with a clean cloth before installation to remove any oils from your fingers that may shorten the life of the bulb.
