What about resetting the time and year after the perpetual calendar is closed?

Unplug the power supply, carefully open the glass panel or back cover (some calendars have a special battery cover behind them, which will be more convenient), and replace the button lithium battery on the circuit board with the 2032 model (which is available in general watch shops and computer maintenance departments, which is very cheap) or the 2025 model. If the problem can't be solved after replacing the battery, you can unplug the 220V power plug, take out the button lithium battery, leave it for 10-20 minutes, then install the lithium battery, plug it in, sometimes the problem can be solved, and then adjust the date and time again. Good luck!