This little encoder fixed the problem
I have not been able to set the time on my microwave oven for quite a while, but suspected it was an encoder problem. A few weeks ago, I had the time to look inside the casing and saw it was indeed an encoder. The ALPS STEC12E07 replacement has fixed the problem. It took just 20 minutes to access replace this device, and my microwave oven now operates as it should. Excellent result.