We have a breadmaker that we don't use a great deal. I'm fond of fresh hot bread, so I suggested to Youngest Son that he learn how to use it and make some. We found the recipe (the manual is long lost), figured some substitutions, and he loaded everything in the machine and .. .. .. oops. The electronic menu was gibberish. Unplugging and replugging didn't help--if anything it was less legible. But we figured the default was probably OK and punched start.
40 minutes later my better half realized the thing was still kneading--the timing system was farbled.
Dump contents in loaf pan and bake. (The bread turned out heavy and crumbly but OK.) In the meantime, google to see if parts are available. (Answer: No. Regal quit making the things 10 years ago.)
The mechanics worked: the problem was in the control system. Maybe something simple came loose, or corroded. There's only one way to find out.
I opened it up and found nothing wrong, but struck with a wild surmise I shoved each connector back and forth on its pins to see if maybe there was contact corrosion. If a CAMAC module misbehaves, the first thing you do to try to fix it is pull the thing out of the crate and re-seat it. Maybe ...
I heaped it back together and plugged it in, and the menu appeared clear as a bell. So I reassembled it and tomorrow we'll see if the timing components work too.
As with all magic tricks, you must never explain it to the audience...