[major]

I have a built in over the stove microwave. It worked great until 2 months ago, then it stopped heating. Everything else works, Turntable turns, the fan underneath works, the control pad is on and works. ... just no heat. So we started using our old on the counter micro.

When I turn the XL 1800 on now, it makes a loud humming noise and I smell electrical smoke. I have checked the GE site for recalls. I called GE and they offered a longer warrranty on the magnetron but I had to pay for a service call for that determination.

I asked GE if they weren't worried about my house burning down and they said that since I called and was aware of the smell, it is now my problem.

Any ideas where to start.

Thank you.

[AmpDraw]

If you run something that has a burning smell when you do so it seems like it should be common sense not to run it and burn your house down. Just to be safe though, if it smells like its burning, you probably shouldn't run it. Since its not working, theres further little reason to run it.

Burning smell, buzzing noise and no heating usually sounds like a bad High Voltage Transformer. Not a recall defect type of thing but a normal to fail sooner or later part of any microwave.

The good news, its probably not going to burn your house down. I've never seen one just burst into flames. The smell is from the coating they apply to the wires making up the transformer. Once the burning smell gets done the next stage of its self destruction is without the coating thats now burned off the wires short out and blow your circuit breaker, you'll probably hear a very loud pop noise when this happens. If you reset your breaker and for who only knows what reason continue trying to run it you'll just keep blowing the breaker.

Common sense should apply and kick in to anyone that if an electrical appliance is making a burning smell it would be a good idea to unplug it and either pitch it in the garbage or pay someone more than its likely worth to fix it for you.

Personally, I wouldn't buy a GE anything after being a residential appliance tech for many years. They make products that sure look good on the sales floor, but once you get them home, well, I'll leave it at that.

Call a local service company, ask them if they can give you an estimate on possibly replacing the "High Voltage Transformer" in this. Which is only a good guess as to the problem you should note, its possible the magnatron or something else shorted out first and is now overloading the transformer causing its wiring to melt. Then weigh that repair estimate against the cost of replacing it completely. If you decide to replace it, both Amana and Whirlpool make very good microwaves. Some of the Kenmore microwaves are made by Amana and Whirlpool, however, some Sears Kenmore products are actually made by GE as well, so use caution when selecting a brand like Kenmore just to be sure you aren't actually getting another GE with the Kenmore label slapped on it.

[major]

The microwave stopped heating several months ago. Nobody has been using it. As I stated earlier, the underneath fan and light works fine with no burning smell.
I recently tried the microwave to observe and make an accurate report for my repair question. Only then did the electric smell occur and then I called GE.

I don't know why you wasted so much of your reply insulting me and talking about common sense. When I made a different repair question on another topic on this web site, I was give a list of possbile repair actions and solutions. I followed this list and was able to repair an electric range.

The microwave is 4 years old, cost over $500, and is a permanent, built-in part of my Kitchen Cabinetry with a custom designed hood which will have to be destroyed to replace or remove to repair. Anyone can just rip out the old and buy a new one. I was hoping to repair mine.

I am hoping someone out there has had similar experience with this model and can share their repair knowledge. I have plenty of common sense, what I need is some microwave repair information. Thank you.

[AmpDraw]

You seemed worried that this was going to burn your house down and more focused on a recall or a lawsuit than actually repairing it yourself. Just wanted you to get your focus away from that direction and aimed at your realistic options. I told you what was most likely wrong with it, there was no indication in your original post that implied you were interested in any way in repairing this yourself.

Here's your parts breakdown...

GE JVM1870SF001 Parts List

The High Voltage Transformer (item #83) is very easy to check, if you have a burning smell you likely won't even need a meter to test it, you'll be able to just look at it and see its melted. Testing it with a meter though is easy enough, set your meter to read "Ohms". There will be likely 4 wires on the transformer, two feed power into it, two are the output side one of the output wires will go to the magnetron, the other to the capacitor. You should read close to zero ohms with the wires off and across the two terminals where the power in wires are connected. Close to zero ohms across the two terminals where the power out wires were connected. No reading at all from either of the power in terminals to the power out terminals and no reading at all from any terminals to the metal around the body of it. It is possible it will read all good on your meter, so if it looks burned or melted anywhere on it its absolutely bad.

Follow the wires and you'll find all the parts making up the microwave circuit. One wire comes off the transformer output side and goes to the magnetron (#61), one comes off and goes to the capacitor (#75), from the other side of the capacitor one wire will go to the other side of the magnetron, a second wire will be going to the High Voltage Diode (#77), from the other side of the High Voltage Diode it connects directly to ground (the metal cabinet).

One of those other items has possibly shorted out causing the transformer to burn out, or the #78 cooling fan has possibly gone bad causing the transformer to get to hot and melt. Its possible the transformer just went bad, but usually its something else wrong in there that causes this to happen. Testing the capacitor and the diode will most likely not be easily done for you with the standard basic meters most people own. Testing the Magnetron is easy, pull the two wires off it and test (ohms) across the two terminals on it, should be pretty close to zero ohms, then test from each terminal on it to the metal body, should get absolutely no reading at all. Sometimes magnetrons test good and are still bad, its a possibility. Sometimes when magnetrons go bad its very obvious, you remove them and look at the end you can't see when its installed. If it look burnt or melted (the little tip sticking out when removed) its bad. If you shake it and hear it rattle its bad.

You need to be aware of the dangers in working inside a microwave yourself though. Even with it completely unplugged from the power that capacitor in there acts like a battery and will store a very painful charge in it. When we work on these the first thing we do is always discharge that capacitor. We do this by carefully removing the wires on it and shorting across the terminals on the top of it with a screw driver, then short them with the screw driver to ground (metal area on the microwave). Sometimes you may see sparks when you do this, particularly if that diode is bad, normally it will be uneventful because the capacitor will have ideally discharged itself after being unplugged from power a short time. I never trust that this has actually happened though, so I'm always sure to short the thing out and discharge it before sticking my hands inside there.

Those are the parts you need to look into though based on what you've described.