Interior cardboard/foil piece fell off revealing small chamber inside oven--still safe?

Interior of microwave ovens are metal, never cardboard. Must be something used for shipping purposes, pitch it.

go to www. repairclinic.com and get it.

God bless you

It should not pose a hazard as far as operation goes.. only if it becomes a sanitary issue..

Clean the interior per mfg suggestions.. and you may have to clean it more often now that you have this issue.

Microwaves cannot travel through metal.. you can actually use small pieces of foil (flat pieces) in most microwaves to shield items.. without any issues.

Best of luck

That is a piece of Mica that is called the Wave Guide Cover.
It is very important as it stops food particles from entering the magnetron output aerial.
You must replace it. Contact an appliance repair centre for replacement.

unless you are familiar with these, leave it alone. Over time small particles of food become carbonized inside the oven, hence the electrical display. the solution is to clean it after every use.

It sounds like what you are describing is called a "waveguide cover". You can purchase a replacement from a local parts supplier, or on-line at www.repairclinic.com. It is very easy to replace.

the disk is just a microwave diffuser but, it is made with a special foil do not put regular foil into a microwave for any reason; just glue the disk back on with ordinary glue

That piece is called the waveguide cover. Emerson calls it a spatter shield. Behind it is the hole where the microwaves enter the oven. Its job is to prevent food spatters from getting into the microwave source, and it's not a good idea to run the oven without it.

The cover is usually held in place by a plastic rivet that pulls out. I couldn't find the part number for the cover used in your model. But here is a link to a parts place that has several covers available:

http://www.a-1catalog.com/wavandstirco.html

If one of the covers shown looks like yours you can order it. Another possibility is to contact Emerson at 800-695-0098. This is the number they give to locate authorized servicers near you, and you might be able to order a replacement cover through them.

Hope this has helped. If so, please take a moment to rate the solution. Thanks for asking here!

No, that is the "waveguide cover".

It provides very important protection for the magnetron.

And always keep it clean according to your manual's instructions.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

check the conductivity of the plastic with an ohmmeter by placing the probes an inch apart on the plastic surface. If the resistance is large or infinity, the plastic probably performs no role in stopping the microwave radiation. If so, any epoxy probably can be used to close the hole safely. Make sure you don't use too much and if possible place tape over the repair and orient the microwave so the epoxy presses against the tape while drying to prevent it from oozing into any door hinge/close mechanism. Otherwise, a piece of microwave door glass from a broken unit can ge glued over the hole and should stop the radiation. You can check for leakage with test units but be very carefuly anyway.