Why has my microwave overheated and now showing 8888 stopped working?

Thanks,

I am a qualified electronics / electrical engineer of over 30 years who can safely work my way around a microwave. The microwaves I normally tackle are much simpler than the current Panasonic. The only unit that will deliver a high voltage shock is the HV capacitor which has been discharged.

Unfortunately the humidity sensor is something that I have never had to test before and have found little information available on how to test, hence the enquiry.

To replace this microwave like for like would cost over £350, not a cheap throw away! Thanks for your concerns anyway.

That is a 700 watt microwave, manufactured around 1988. I can buy a better made microwave with more wattage and functions, new, for less than $60 USD. Perhaps you gave us the wrong model number?

Thanks,

model number correct (NN-6808, board number A603L478) but getting back to my original question do you know how to test the humidity sensor or where I can get the part?

The board is available at http://www.partstore.com/Model/Matsushit... as special order or http://www.qualityelectronicrepairs.co.u... Still checking on a service manual, but tough to find :-)

The humidity sensor can be obtained from a number of sources. The Part # is A601L4780AP. I would do a Google on the part number to find a provider close to you to save on shipping cost. Without a known good part, the schematics and/or service manual it is not possible to accurately answer your question on how to properly test it. The temperature and humidity sensors on microwaves such as this are known to be problematic and one of the components that need replaced before most of the others.