Fiber plate inside microwave burned out- Sugges Alternative

That normally occurs when there is metal inside this is assuming it is coming from the inside of the cooking chamber. There should not be any metal in there as it causes a short and will burn up the magnatron in a retaliative short time.

Hi there
It is called the waveguide ocover and is made from polycarbonate

The magnetron is getting to hot and will eventually fail, especially when it is arcing, "a safety issue convern" the cause is the part mentioned above, or there is exposed metal on the inside cavity.

these covers are made of a mica material; and tend to get grease-soaked from food splatter. this is where the microwaves pass through. if cover is burned, you will need to replace and clean greasy mess underneath. hopefully, the magnetron is not damaged.

The ALLUMINIUM FIBER PANEL is to prevent microwaves to erradiate whatever is on the other side, so YES it is essential, and YES the oven will worke (BUT FOR HOW LONG ???) that is the question... you should replace the panel (unless the oven is old and you were planning to replace it) in that case, use it until it dies...

When food soils the inside of any oven it must be cleaned immediately, if the food is left without cleaning it will degrade the inside coating (special paint) and expose the metal thus reflecting microwaves in the magnetron and damage to the magnetron will occure...

Cheers!

Arcing in or above oven chamberThere is often a simple cause:

• Arcing in the oven chamber with a normal load (a cup of water, for example), often just indicates that a thorough cleaning of the oven chamber is needed, particularly around and inside/above the waveguide cover. Any food that gets trapped here will eventually burn and carbonize resulting in a focal point for further arcing. Usually, the waveguide cover is designed to be removable without taking the (cabinet) cover off of the oven. However, burnt food and carbon often make this difficult so that some disassembly will be required. See the sections: "SAFETY" and "Getting inside a microwave oven".

for more information see "Arcing in or above oven chamber" section of online Microwave Repair Manual.
If the microwave is clean, please post a reply and I will look at it again (this time include a model # and/or approx manufacture date)

If your microwave has a turntable its probably just burnt food inside or above the oven chamber that has carbonized. If it doesn't have a turntable its possible the stirrer above the oven chamber is stuck and not moving the microwaves around, therefore causing over heating and arcing. It also could be that the stirrer blades are hitting inside. Hope this helps

Sparks in microwaves are caused by metal things in there. What kind of plate - any metal or gold leaf decoration on it?
Try a microwave safe dish.
Make sure you do not use metal items in microwaves.
I do not know the model number of your nuker, is it a new one or old? How long have you had it, and has it always done this?

pls do not use any aluminum or metal material INSIDE the microwave, this can cause the problem

I assumed, but pls consider the ff info...

Be sure to use nonmetal utensils in the microwave.

For microwave cooking, cut meats and vegetables in uniform sizes to make sure that they cook evenly.

Paper plates, cups, and napkins can be used in the microwave. But don't use foil-lined paper products, paper towels that include nylon or synthetic fibers, or newspaper.
When using plastic roasting or cooking bags in the microwave, discard the wire twist tie and use a plastic fastener or a piece of string instead.

To ensure that food cooks fully and evenly in the microwave oven, stir food and turn dishes periodically while they're cooking.

A LOUD ticking sound could very well be a High Voltage Arc. This is usually caused by a breakdown of insulation on High Voltage Wires, or components. It can also be arcing between the door frame and the cavity. Usually where the bottom of the cavity floor meets the door frame. Indication of this will be small areas on the door where it looks like the paint has been chipped off, but if you look close you will see it is small burned marks. Another area is the Splatter Shield located inside and at the top. It looks like a Plastic Cover. It is not plastic, but a fiber material. Grease, and food will get trapped on and under this Splatter Shield. Over a period of time the grease and food particles will break down from being cooked over and over again. They will then form Carbon. Which will Arc when Microwaves are present. Remove Push-Pins holding Splatter Shield. Clean by washing with dish detergent . If burned (arc) spots are still present after washing, replace Splatter Shield or arcing will continue. Once Carbon has burned through, it will continue to burn.