If the display on your digital watch is not working or not showing the correct display then it is likely that the watch needs to be reset. If you remove the back again, you should see some indication of a reset hole on the watch’s movement. This is sometimes marked with the letters “AC” (All Clear).

This needs to be shorted out against the case of the watch or the top of the watch battery. Using a paper clip or a pair of metal tweezers place one leg into the hole marked “AC”and touch the other leg against the main movement housing or the watch battery (creating a temporary short circuit). This should reset the display.