Thank you Greg, that it exactly it -- a humidity sensor.
I thought it is kind of a sensor or a fuse, but couldn`t put my finger to the exact nature.
Now I just need to find a vendor that ships this little part to Canada. Would be sad to throw away a 500$ microwave oven (Panasonic NN-C980B) just because this little thingie has died.
And to StikyBoots: thank you for the warning, I would never work on the microwave that is not unplugged. I even waited for 48 hours before starting to disassemble.
If you can't find it at your local appliance parts store then you could try searching the part number at FixItNow.com. They may also offer free returns if it's not the correct part.
Short out the terminals of the high-voltage capacitor (with a shorting probe or something other than your anatomy) and you'll be fine.
I wish everyone's dire warnings of DIY doom would be augmented with a practical suggestion on how to safely accomplish the task instead of merely "OMG seek professional help or you'll die a horrible disfiguring death!!"
I'd also appreciate a link to the statistic quoting the 2013 microwave fatality report.
I'm with you, Nords. DIY is not hard, you just need to do your homework and take the proper precautions.
If the microwave has a large capacitor (i.e. not inverted based), what you want is a shorting stick. It's an insulated stick that has a wire with an alligator clip on one end, a metal probe on one end, and a 1K resistor in between (to prevent arcing). You attach the clip to the chassis or other grounded surface, then touch the probe to the positive terminal of the capacitor.
I use something similar as a precaution when working on my high-power vacuum tube RF amplifiers. I am an amateur radio operator, and one I use now runs 3600V. I do my own repairs on that. They do have a bleed resistor to drain the caps, but that's one of the more common failure points. :)
