Forgot to mention, yesterday's fiasco was fixing the microwave that suddenly quit. The diode and cap tested good, which left the magnetron. I did check the door switches but it sounded like it was running, and when I did check them, they seemed fine--but I never checked the hinges. While hemming and hawing, I noticed that the primary winding on the transformer looked liked it had gotten warm. Given how it'd take a week for parts to show up, and that, if not careful, I might hit half the cost of new, I pulled the plug and replaced it.
Had to use the kids CRV to go and get the new one. Did not realize how low on power that car is--my Corolla is a rocket by comparison. He's not complaining, so I'm not fixing, but maybe that CEL is actually for something important. [I think the flat exhaust lobe on one cylinder is part of the blame but it's not missing, yet.] My main takeaway was to avoid driving his car as much as I can (but it's the only one with a big boot).