a) The display screen may change when you open the door, especially if you haven't yet opened it after the oven turned off. There may be a beeper that goes off to tell you the oven has shut off.
These types of things are turned off during Shabbos mode.
b) Ovens today will often shut off after 12 or 24 hours of running, and that is overridden by the Shabbos mode.
BUT: I briefly had a JennAir that didn't need a Shbbos mode. I could adjust the settings to beep once after it turned off. And not change it's display screen. And not turn off after 24 hours.
Alas the mother board died and I moved on to an ordinary oven that needs a Shabbos mode.
Curios how did you know the motherboard died? Meaning the entire display?
I have a stackable oven which i'm trying to understand why the bottom works and top doesn't, try swapping the element from bottom to top and still doesn't work, so I know I have a working element.(For some off reason my Multi meter was working so had to test it manually).
Just curios if your whole oven went ka'poot or you had a stackable and one went?
I'm thinking to check the relay switch/fuse in the back of the oven, if not then it's the motherboard which I didn't want to change.
I started to work on the oven while the electric was still connected and I manage to cause the breaker to blow, that shows there's electric coming to the element but for some odd reason it's not working.
Have to have time and patience to properly diagnose it. ( No its not my oven at home otherwise I would be busy during these Quarantine days at home.)
I have a basic cheap GE oven and it has shabbos mode. Even if its not advertised try googling to see if your cheaper version also has shabbos mode
Yes the basic GE ovens have the shabbos mode by holding bake and broil together and...
While the more expensive ones allow you to open and close the oven door and take out stuff from the oven.
Everyone has their own shee'tas when it comes to ovens about opening and closing the doors.
I just saw recently an oven where someone was showing me he's allowed to lower and make higher the temperature when the oven is off and it's allowed because it's only a gramma and.. I didn't really pay attention to what he had to say, as I'm not bekant in the sugya so was gibberish to me.