mm writes:

If only. I have junk piled in front of the microwave, and I wish it
would stop in the same position it started.

I've been trying to keep track of how long a rotation takes, but I
forget now. Should I make some tests? Does it matter what brand of
microwave I have? From what you say, it doesn't seem to.

Yeah, it would depend on brand. All the ones I've had with turntables
were 10 seconds/turn, but that doesn't mean everybody uses that rotation
rate. And the "always run the motor an integer number of turns" is a
software feature that might not be in some controllers, though I've
noticed it in the ovens I've used.

My impression is that it continues to run while it is beeping. I can
tell when the magnetron turns off by running a radio on a fairly weak
station next to the oven. Which I do a lot of the time, because I
listen to two stations 50 miles from here.

You can usually tell that the magnetron is on by the humming from the
high-voltage transformer. Set the oven to 50% power, and you should
hear the transformer hum turn on and off with about a 50% duty cycle and
a period of perhaps 15 seconds.

Dave