Do you have a question about the Casio SF-3990 and is the answer not in the manual?
Steps to load batteries and reset the unit before first use.
Instructions on how to increase or decrease the display contrast.
Steps to choose the desired language for the device interface.
Guide to selecting and displaying different world cities for timekeeping.
How to toggle between Standard Time and Daylight Saving Time.
Instructions to switch between 12-hour and 24-hour timekeeping formats.
Step-by-step guide to setting the desired alarm time.
Explains using CAPS, SHIFT, SYMBOL, and CODE keys for character input.
How to navigate and find data by scrolling through entries.
How to find data by entering the first characters of the entry.
Instructions to remove one specific data entry.
Steps to erase all data within a selected mode.
How to set up a password for the secret memory area.
Steps to access the secret memory area using the password.
Procedure to update the existing password for the secret memory.
Demonstrations of various arithmetic operations and their results.
Step-by-step instructions for safely replacing the unit's batteries.