Philips M702/M704 microwave

[boater sam]

As stated above the stirrer types work the best.
It was common on early microwave ovens.
Belts and motors were common as was seized bushes on some of the Japanese ovens.
Unless you have done the industry standard Sharp microwave oven training course it was illegal to open up a microwave oven, engineers caught doing this in the big companies could be instantly dismissed.
Why.... There were deaths early on.

My company worked on thousands of microwaves. We trained engineers to work safely on all appliances.The high voltage and high current capabilities of a transformer supply  had to be understood, appreciated and carefully evaluated.
There are very few reasons for ever working on an oven connected to the mains. Understanding the potential of a charged capacitor to kill has to be considered.We never had an incident in 36 years.