Ok, a little more information as well - it turns out that it does still heat up food. I put some rice in there to see if it would heat up, and it did. But when the rice was in there, it didn't make any of the buzzing sounds it did before. I took the rice out, and it went right back to the buzzing. Put some more stuff in to heat up, no problem, but when I tried it with nothing in it it makes the buzzing noise.

If I look up in the vent area, it looks like it might be arching inside the unit when it makes the loud buzz sound. I took out the turntable that's in there and made sure everything was clean, but I still have the problem. I tried to run it without the turntable and still have the problem. I tried to get the gear (not sure what you call that thing that moves the turntable), but it didn't seem like it wanted to come off. I cleaned it up good and there doesn't appear to be anything on it, but when I cover it I don't seem to have the problem.

Any help would be great!

Thanks.

- m

Ok - never really ran it with nothing in it, but just wanted to do some trouble shooting. It seems that as long as we have something in there, it works fine.

What causes it to arc? Is there something I can do to prevent it from doing it again?

After an inspection of the inside, there is a very minor scratch/dent where a very small area of metal is exposed - could that be the problem? Should I paint over that?

Thanks for all the help!

Please see my post from today about my microwave only heating when the vent fan is on.

I have a GE spacemaker XL1800 model JVM1870BF03. It began making a loud humming noise when cooking and after a week or so it quit heating all together. I read your forum and based on the info I replaced the magnetron. The old mag had a burn hole at the end of the stem. The first mag GE sent made a funny humming sound and didn't heat so I sent it back and GE sent me another one. I just put it in, it sounds fine but still doesn't heat, am I missing something? All of the other features work fine, I even tried the defrost mode and I can hear the power cycling on and off.

GENE mine does all of the above.. but no noise or smell... lights up, turns, counts down but no heat... Let me say my son put a piece of tin foil in 3 weeks ago.. I caught it within 5 seconds... but there are burn marks on te door and rear of the inside... It worked fine for 3 weeks and yesterday simply stopped heating. I did the Defrost test. it does NOT cycle on and off like it used to....

Where do you think I am on this? Its a 2005 model. THANKS! Brian