I have a rival microwave model rgst902 and i believe the waveguide cover needs to be replaced. How abd where could i get it for this particular model?

If your microwave's waveguide cover is severely burnt, it is generally recommended to replace it rather than repair it. The waveguide cover is designed to be transparent and protect the antenna or magnetron from food splatter and grease. To replace the cover, follow these steps:
1. Identify the replacement part number from your microwave's user manual or contact the manufacturer.
2. Order the part from the manufacturer, authorized dealers, or reputable appliance parts suppliers.
3. Turn off the microwave to ensure safety.
4. Remove the old waveguide cover and secure it using screws or clips.
5. Place the new waveguide cover in the same position and secure it using the appropriate screws or clips.
6. Test the microwave to ensure the new waveguide cover is in place and functioning correctly.
Replacement is crucial as a burnt or damaged waveguide can affect the microwave's performance and cause further damage to internal components. If you have any doubts or are uncomfortable with the replacement process, seek professional assistance or contact the manufacturer's customer support for guidance.

What kind of cover? Is it a greyish/tan cover on the inside of the oven cavity on the right hand side? If so, it's called the waveguide cover. I'm guessing it started arcing and burning... try 'googleing' the model number to see if you can find any information on it.
Call Appliance Factory Parts in Denver to see what they can find for you 303-761-1111. Or look them up on the web...

Repairclinic.com among others.

www.rivalproducts.com/...support/...support/.../microwave.../microwave

The unit is not producing microwaves, therefore replace it.

Bad element. Replace.

Rival
c/o JCS/THG, LLC
13120 Jurupa Avenue
Fontana, CA 92337
Telephone: 1-800-323-9519

Check for a Fuse