Bought microwave from a friend yesterday for $50, she said its new but has been sitting in storage for long time, had box and packing and even plastic film on display panel. Took it home and works great except for burning plastic/rubbery smell whenever its used. Took top panel off (GE brand- JES1451DN1BB, made in 2010, yeesh that's old, but looks new) just to see if I can see any problem. (I've never de-energized a microwave so I didn't touch anything inside) I saw this:


Could this be the only problem? I see no other issues while looking at everything else with flashlight. And can I touch that area without being shocked to death? Looks like just a loose connection that got hot, it runs great, no noises, just that burnt wire smell. I watched a video about how to de-energize and the guy did it with insulated needle-nose pliers, it don't look too hard if its necessary. If this was a toaster or something I would clean it up and see whats left under that burn area then either solder or replace that connector but I know nothing about microwaves. Any advice is appreciated, thx.

edit- having picture issues- see if this works:
https://imgur.com/a/pxGVptE
LOL now I can see it....

 

That looks like a poor connection that is heating up. Maybe it was a poor connection from the factory or some corrosion grew while it sat in storage. I would redo that connection with a new, insulated female spade socket.

 

The device with the burned connection appears to be for thermal overload. It would open its contacts on high temperature in the area. The burned connection is usually a female wire end held in place by friction with the tang on the thermal overload. In the photo, there also appears to be a screw head at this connection. Can you verify? If there was an overcurrent problem, I would expect the wire connection on the opposite side of the thermal overload to also be burned. It appears not. Did anything get spilled on the microwave before/during using?

 

I thought that was a screw too but just a circle in the plastic. I cleaned it up and the metal looks fine and I reattached it and squeezed it with pliers and it seems like it should work. Would it be a sin if I just used electrical tape and checked it after each use for the first week? Whatever that part is it looks identical to the one mounted to the ceiling of the cooking area, which the burnt wire leads to after passing through that blue thing. No spills. Found an envelope with schematics inside when I opened it.

https://imgur.com/a/AjpdUjs

 

That is a thermal sensor monitoring the magnatron high heat level.
With that type of damage it needs to be replaced.
That should be a WB20X10003 thermal sensor.
The connector that was burned also needs to be replaced.

 

And from what I can find, they are not very expensive, cool thx, and thanks for the help of all who replied. Now I just gotta find out if the friend who sold me this knew it had issues or didn't know.