[Melissa2012B]

We have this Sharp Carousel microwave and it's about 6 years old. It just started arcing last night, at the place where the microwaves enter the cooking chamber, on the right wall - big yellow flashes and smoke.

I tried cleaning it with a damp paper towel, but it still does it and there's flakes of something that looks like mica, coming off on the paper towel.

So I'm thinking we need a new oven, but not so fast...

I'm a 63 year old electronics technician and was just looking at Amazon.com for new ovens, which cost a LOT ( this is a good sized counter top unit and over 1000 watts if I recall ), and came across waveguide covers, which are only a few bucks each. Can that just be replaced, if I get the model number off the back?

I'm thinking that food may have spattered on it over time and it finally arc'd over.

[denman]

Yes they can be replaced if you can find the correct one.

Some of them just clip in others require taking the unit apart.

As a test I would just remove it and see if it still arcs.
If it requires taking the unit apart I would just carefully cut it and remove it from inside the oven.
This is just for testing, do not run the unit like this.
Try heating up some water with a loose cover do not let it come to a full boil.

If it still arcs then either the magnetron or it's control electronics are bad and I would replace the unit.

If it does not arc then hunt up a replacement and install it.

If you have to take the unit apart be very, very careful.
Many older units do not discharge the high voltage when the unit is off/unplugged so you can get a nasty shock or worse.

[Melissa2012B]

I pulled on it some, it seemed loose, so it looked like it would bend a little and pop out from behind the tabs. It did, no problem. I'll go test it without the cover now, as you suggested, thanks!

[ckajua]

Last week I started having arching problems on my Sharp Carousel microwave oven. After I placed an order on Amazon.com for a microwave guide cover, I came across this helpful link on Yahoo!:

<< How to Fix a Sparking Microwave Oven
Repairing Your Microwave May Not Be as Hard as You Think >>

It involves thoroughly cleaning the microwave guide and the microwave guide COVER! Here is the link:

How to Fix a Sparking Microwave Oven - Yahoo! Voices - voices.yahoo.com

If it does not open, copy and paste to your browser address box.

I tried the tip and it worked. My Sharp carousel is again operational! I hope this helps.

[Melissa2012B]

Success! I actually found the correct model number on the label inside the door. Tested the oven per suggestion here, it's fine. Found a mention of which cover was for that oven, on Google, then ordered one on Amazon.com. It's on the way. Thanks guys!

[Melissa2012B]

By the way, when I tested it with a cup of water and no waveguide cover, it heated the water some, but not as much as it usually would. Does not having that waveguide cover on there change the microwave distribution ( SWR? ) enough to screw up the power it delivers to the water?