Casio F91W Series Digital Watch Instruction Manual

Introduction

Thank you for choosing the Casio F91W Series Digital Watch. This classic timepiece offers reliable digital timekeeping, a stopwatch, daily alarm, and an LED light, all within a durable, water-resistant design. This manual provides comprehensive instructions to help you get the most out of your watch.

Image 1: Front view of the Casio F91W Digital Watch in Clear Blue. The display shows the time, day, and date, with "LIGHT", "ALARM CHRONOGRAPH", "WATER RESIST", and button labels visible.

Button Functions

Your Casio F91W watch features three buttons for operation. Refer to the image below for their locations:

Image 2: Overhead view of the Casio F91W Digital Watch. The buttons are located on the left and right sides of the watch case. The top-left button is the Light button (A), the bottom-left button is the Mode button (B), and the bottom-right button is the Adjust/Start/Stop button (C).

• Button A (Top Left): Activates the LED backlight.
• Button B (Bottom Left): Cycles through modes (Timekeeping, Alarm, Stopwatch, Time Setting).
• Button C (Bottom Right): Used for setting values, starting/stopping the stopwatch, and toggling 12/24-hour format.

Setup and Timekeeping

Setting the Time and Date

1. From the normal Timekeeping Mode, press Button B (Mode) three times until the seconds digits start flashing. This indicates you are in Time Setting Mode.
2. Press Button C (Adjust) to reset the seconds to 00.
3. Press Button B (Mode) to move the flashing selection to the hours.
4. Press Button C (Adjust) to advance the hour. Note the 'P' indicator for PM hours.
5. Press Button B (Mode) to move the flashing selection to the minutes.
6. Press Button C (Adjust) to advance the minutes.
7. Press Button B (Mode) to move the flashing selection to the month.
8. Press Button C (Adjust) to advance the month.
9. Press Button B (Mode) to move the flashing selection to the date.
10. Press Button C (Adjust) to advance the date.
11. Press Button B (Mode) to move the flashing selection to the day of the week.
12. Press Button C (Adjust) to advance the day of the week.
13. Press Button B (Mode) to exit the Time Setting Mode and return to normal Timekeeping.

12/24-Hour Format Selection

In the normal Timekeeping Mode, press Button C (Adjust) to toggle between the 12-hour and 24-hour (military) time formats.

Operating Modes

Cycling Through Modes

Press Button B (Mode) to cycle through the watch's different functions in the following order:

• Timekeeping Mode (default display)
• Alarm Mode
• Stopwatch Mode
• Time Setting Mode (as described above)

Using the Daily Alarm

1. From Timekeeping Mode, press Button B (Mode) once to enter Alarm Mode. The alarm time will be displayed.
2. Press Button C (Adjust) to set the alarm hour.
3. Press Button B (Mode) to move the flashing selection to the alarm minutes.
4. Press Button C (Adjust) to set the alarm minutes.
5. Press Button B (Mode) to exit alarm setting.
6. While in Alarm Mode, press Button C (Adjust) to toggle the daily alarm ON or OFF. An alarm indicator (bell icon) will appear on the display when the alarm is active.
7. To toggle the Hourly Time Signal (chime every hour) ON or OFF, press Button A (Light) while in Alarm Mode. A chime indicator will appear when the hourly time signal is active.

Using the Stopwatch

The stopwatch measures elapsed time in 1/100-second increments.

1. From Timekeeping Mode, press Button B (Mode) twice to enter Stopwatch Mode. The display will show 00:00:00.
2. Press Button C (Adjust) to start the stopwatch.
3. Press Button C (Adjust) again to stop the stopwatch.
4. To reset the stopwatch to 00:00:00, press Button A (Light) while the stopwatch is stopped.

Using the LED Light

Press Button A (Light) in any mode to illuminate the display for a few seconds. Note that the light is designed for basic illumination in dark conditions.

Maintenance

Water Resistance

Your Casio F91W watch is marked as "WATER RESISTANT". This means it is suitable for everyday use and can withstand splashes, rain, and brief immersion in water (e.g., hand washing). It is not designed for swimming, diving, or prolonged water exposure. Avoid operating buttons while the watch is wet to prevent water entry.

Cleaning Your Watch

Wipe the watch with a soft, dry cloth to remove dirt and moisture. For stubborn grime, a slightly damp cloth can be used, followed by immediate drying. Avoid harsh chemicals or abrasive cleaners.

Battery Replacement

The watch is powered by a CR2016 lithium battery, with an approximate life of 7 years. When the display becomes dim or functions become erratic, it may be time for a battery replacement. It is recommended to have the battery replaced by a qualified watch technician to ensure proper sealing and maintain water resistance.

Troubleshooting

• Display is blank or dim: The battery may be low or depleted. Replace the battery.
• Time is incorrect: Re-set the time and date following the instructions in the "Setting the Time and Date" section.
• Alarm does not sound: Ensure the alarm is activated (bell icon visible) in Alarm Mode.
• Hourly Time Signal does not sound: Ensure the hourly time signal is activated (chime icon visible) in Alarm Mode.
• Buttons are unresponsive: Ensure the watch is not exposed to extreme temperatures or strong magnetic fields. If the issue persists after a battery change, professional inspection may be required.

Specifications

Warranty and Support

For warranty information, please refer to the warranty card included with your purchase or visit the official Casio website. For additional support or inquiries, please contact Casio customer service.

An official user guide in PDF format is also available for download: Casio F91W User Guide (PDF)