Question about Panasonic NN-SN657SMicrowave Oven

1 Answer

Arking through the heat-vapour barrier(MICA cover) The arking actually burned through the MICA. I replaced the MICA with lexan, but now the oven shuts off before the specified time and is barely heating water.

Posted by on

  • 5417376 Sep 25, 2009

    Thanks "Fixer", you are right the fumes coming from the oven was auful when I thested to see if the lexan would work. By the way my oven is the Genius sensor NN-T695SF 1300 W. unit and I got a part number and a $20 price for the Mica-cover. As you rightly observed, there must be a cause of the burn-through. I may buy and replace the mica without achieving a fix. I recall that the arking started when I placed a cup with gold rim. Maybe that provoked the inetial burn-through giving the discharge an unhampered path.



    So the BIG question is: Will replacing the mica cure the low power and eratic truncation of the assigned time that I enter for a given task? Note, the lexan seems to have stop the arking.

  • 5417376 Sep 25, 2009

    So it seems that I will have to throw this out there to see if someone is particularly conversant with whether ithe mica is responsible for the power level of the oven. By the way I did not place mica in or on the window, just in place of the burned through mica.

×

1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    President:

    An expert whose answer got voted for 500 times.

  • Master
  • 2,976 Answers

Don't use your microwave with Lexan in the window. When heated, Lexan gives off extremely toxic gasses. It can also catch fire. If you need to replace the mica, use the original product to replace it. There has to be a reason, that the mica burned through. If you are using a home style unit, it isn't made for institutional use. Home use microwaves will tolerate about 25% as much use as a industrial, or institutional microwave, in a 24 hour period. The amount of moisture that gets into the original window in a home unit is normally a lot lower. If you do a lot of cooking where there is a lot of water involved, you will also have moisture problems. A way to fight this, is to either wipe the moisture from the inside when you are done, or leave the door open, so the moisture can evaporate.

Posted on Sep 25, 2009

  • David Shaub Sep 25, 2009



    I totally destroyed my old microwave this way. I had a plate with a 1/4" gold stripe around it. I thought it was just paint. WRONG. I never saw so many pretty colors before. When you put the cup with the gold rim in, you actually vaporized gold into the insides of the oven. For safety's sake, buy the mica shield. When you have it apart, wipe everything with denatured alcohol. It cleans much better than rubbing alcohol. Liik for gold deposits and remove them. If you have a shelf in the unit, make sure the edges are as clean as new.

  • David Shaub Sep 25, 2009

    Mica will insulate at the rate of about 1000 volts per 1/16 inch. It ia also a fantastic heat shield. If moisture got into the original mica sheeting, it destroyed the mica. Since you put lexan into the same area and you smell it when you use the oven, I'd replace it with another piece of mica. Check the component that the mica is next to. It's probably a high discharge capacitor. Make sure it has no signs of damage.

    I originally thought you were talking about the shield in the door, the window. We've had it describad as almost anything you can imagine.

×

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
goodluck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Massive sparking and noisy when switched on to heat


Hi,
There are 2 things that cause the massive sparking:
1. you placed inside the microwave oven a metal plate or one with silvery or golden drawings;
2. the mica sheet that covers the magnetron window is compromised (has holes, it is cracked) or it is covered with burnt (carbonised) food.
You have to carefully inspect the mica sheet and wash or replace it, if necessary. Hope that helps.
Regards,
Dan

Oct 10, 2016 | Microwave Ovens

2 Answers

Hole burned in panel inside next to ligt


take it in for repairs or just replace it

Apr 26, 2015 | Sharp Microwave Ovens

1 Answer

Why is there a burn hole inside the oven, on the cardboard?


That's actually a mica "window" (cover) for the microwaves to come out. And it sounds like the magnetron started arcing and burned a hole in that cover. Either that, or some food (frequently spaghetti sause) got splattered on it, and the microwaves heated it up so much that it burned a hole in the cover. Does the microwave oven still work (heat)? Do you see or hear any arcing? If the microwave oven still works and there is no arcing, you can just replace that cover. Check SearsPartsDirect.com or RepairClinic.com.

Jul 10, 2014 | Kenmore Microwave Ovens

1 Answer

I get an occasional spark when microwave is in use


Presuming that you have iliminated the possibility of any metal objects that are not meant to be in the machine being in there (and this includes dishes and other items with silver or gold leaf on them, which WILL spark and burn!) then take a look inside the oven its self. You will find a waveguide cover. It is usually a strange flakey silvery plastic/card like material called Mica and is usually on the same side of the microwave wall as the control panel (So if the picture on this thread is accurate, I will guess the Mica cover is on the right hand wall inside as you look at the machine from the front) . Over time, the magnatron (the thing that creates the microwave energy) will often burn a hole through the mika, or cause a dark brown or black burn mark in it. If this cover is even slightly damaged then it may well cause sparking inside the machine. These covers are designed to be removed and you can buy replacements for them from electrical stores.

Aug 12, 2011 | GE Advantium SCA1001HSS Convection...

1 Answer

Sparks are coming from behind the little revovable plate inside the oven.


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.

Aug 06, 2011 | Jenn-Air JMC9158AA Convection Microwave...

1 Answer

Microwave not heating


Bulb is probably burned out or the Mica cover located inside the oven has holes in it.
Replace both with parts from any local appliance store. Make sure the vendor doesn't charge you more than 50% of the new purchase price. Sometimes it's cheaper to just discard and purchase a new one.
TF

Jun 03, 2011 | LG Microwave Ovens

1 Answer

We have a ge microwave. Sparks came out of


Quite often this is due to grease or food particles stuck to the inside of the oven or stuck on or behind the mica waveguide cover.

The waveguide cover is usually about the size of a playing card and often held in place by a plastic rivet.

Sometimes it is the ceiling of the oven.

Your owner's manual may address this. You can download GE owner's manuals and installation instructions here.

It can be fragile, and the metal edges of the oven behind it can be sharp, so be careful!

The cover and the metal behind it should be cleaned with a mild, non-ammonia cleaner.

If the cavity metal of the oven is chipped or charred, it will have to be sanded smooth and clean.

Then you can apply some high-temperature appliance paint, available from places like Wal-Mart or Lowe's.

If your waveguide cover is burned, it will need to be replaced.

You can find helpful exploded view diagrams and order parts by entering your full model number here.

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

Oct 10, 2009 | GE JES1290SK 1.2 Cu. Ft. Countertop...

5 Answers

Metallic-like cardboard insert inside microwave is crumbling???


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!

Mar 03, 2009 | Emerson MW8102SS 1100 Watts Microwave Oven

2 Answers

Sparking roof of my miele M613G microwave


these ovens are favourite for this, it is something to do with the stirrer blades. the top casing can be removed and replaced

Feb 23, 2009 | Miele M613GSS 800 Watts Convection /...

1 Answer

Smoke Coming from inside of Microwave even when warming for 10 seconds


Proberly wave guide cover at side it can get grease behind it,And when you used it with small load it tried to cook it and then burned the mica cover,Take mica cover off and try it without it to seeif problem resolved if ok,New cover can be obtained if req.Regards grandadfixer

Oct 10, 2008 | Thermador MBBS Microwave Oven

Not finding what you are looking for?
Panasonic NN-SN657SMicrowave Oven Logo

Related Topics:

120 people viewed this question

Ask a Question

Usually answered in minutes!

Top Panasonic Microwave Ovens Experts

William Miller
William Miller

Level 3 Expert

9047 Answers

Devabhakthuni...
Devabhakthuni...

Level 2 Expert

225 Answers

Jerry Greenberg
Jerry Greenberg

Level 3 Expert

1667 Answers

Are you a Panasonic Microwave Oven Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...