Change the lightbulb - Microwave Ovens

Take the outer case off light will be accessible for you to change it

I assume you want to know how to change the light bulb.
First, unplug the oven. Check inside the oven cavity to see if there is a removable bulb cover (I haven't seen one in there yet, but I haven't seen every model ever made). Next, look for a light-bulb sized door on the back, held closed with a single screw (some Litton designs have this).

If you don't see any easy access like this, then you need to remove the top / side cover. This is usually held on with 1/4" hex or #2 Phillips screws.

CAUTION: on the right side of the oven, behind the big transformer are a high voltage diode (a black-colored block or cylinder about 1/2" to 1 1/2" long with two terminals or leads) and capacitor (an oval-shaped can with some terminals on one end). The capacitor may hold a charge even with the oven unplugged. DON'T touch the wiring to these three parts! Also, don't touch the stuff behind the control panel. You can damage it with an electrostatic shock.

With the cover removed, you may see the light bulb on top of the oven cavity. Sometimes it has an additional cover over it - you should be able to identify it by the location of the light bulb window inside the oven. While you have the cover off, you can blow the dust out of the fan and vent holes.

When you replace the cover, be sure any tabs on the inside of the cover are properly engaged as you slide it forward.