Introduction
Thank you for choosing the Casio F-91W-3DG Digital Watch. This manual provides detailed instructions for setting up, operating, and maintaining your watch to ensure optimal performance and longevity. The F-91W-3DG is a classic digital timepiece known for its reliability and practical features.
Setup
Initial Time Setting
Upon first use or after a battery change, you may need to set the time and date. Your watch features three buttons: Light (top left), Mode (bottom left), and Alarm/24HR (right).
- Press the Mode button repeatedly until the time display flashes, indicating it is in setting mode.
- Use the Alarm/24HR button to adjust the flashing digits (hours, minutes, date, month, day).
- Press the Light button to cycle through the different settings (hours, minutes, month, date, day of week).
- Once all settings are correct, press the Mode button to exit the setting mode.
Figure 1: Front view of the Casio F-91W-3DG watch, showing the digital display and buttons.
Operating Instructions
Time Display
The default display shows the current time (hours, minutes, seconds), day of the week, and date.
Alarm Function
To set the alarm:
- Press the Mode button twice to enter the alarm setting mode.
- Use the Alarm/24HR button to adjust the hour.
- Press the Light button to switch to minute setting, then use Alarm/24HR to adjust minutes.
- Press the Mode button to return to normal timekeeping.
To activate/deactivate the alarm, press the Alarm/24HR button while in normal timekeeping mode. An alarm icon will appear/disappear on the display.
Chronograph (Stopwatch)
To use the stopwatch:
- Press the Mode button once to enter stopwatch mode.
- Press the Alarm/24HR button to start/stop the stopwatch.
- While the stopwatch is running, press the Light button to record a split time. Press Light again to release the split time and display the current running time.
- To reset the stopwatch, ensure it is stopped, then press the Light button.
Illuminator (Light)
Press the Light button (top left) to illuminate the display for a few seconds in low-light conditions. Note that the illuminator provides a modest green backlight.
12/24-Hour Format
To switch between 12-hour and 24-hour time formats, press the Alarm/24HR button while in normal timekeeping mode. The display will show 'PM' for 12-hour format afternoon times or '24H' for 24-hour format.
Maintenance
Cleaning Your Watch
Wipe the watch with a soft, dry cloth. For stubborn dirt, use a soft cloth dampened with water and a mild soap solution, then wipe dry. Avoid using chemical cleaners or solvents as they may damage the watch's finish.
Battery Replacement
The Casio F-91W-3DG uses one Lithium Ion battery. The battery life is approximately 7-10 years. When the display becomes dim or the watch stops functioning, it's time to replace the battery. It is recommended to have the battery replaced by a qualified watch technician to ensure proper sealing and maintain water resistance.
Water Resistance
This watch is water resistant to 3 ATM (30 meters), meaning it is suitable for everyday use and can withstand splashes or brief immersion in water. It is not suitable for swimming, showering, or diving. Avoid operating buttons while the watch is wet to prevent water ingress.
Figure 2: Rear view of the watch, highlighting the stainless steel case back and water resistance marking.
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 'Setup' section. Ensure the 12/24-hour format is correctly set.
- Alarm does not sound: Check if the alarm function is activated (alarm icon visible on display). Ensure the alarm time is correctly set.
- Light is too dim: The F-91W-3DG features a modest illuminator. If it appears unusually dim, the battery may be low.
Specifications
| Feature | Detail |
|---|---|
| Model Number | F-91W-3DG |
| Movement | Quartz |
| Display Type | Digital |
| Case Material | Plastic |
| Band Material | Resin |
| Crystal Type | Mineral |
| Water Resistance | 3 ATM (30 meters) |
| Functions | Time, Date, Day, Alarm, Chronograph, Illuminator (Light), 12/24-Hour Format |
| Battery Type | 1 Lithium Ion battery (included) |
| Dimensions (L x W x H) | 1.5 x 1.31 x 0.33 inches (38.2 x 33.3 x 8.4 mm) |
| Weight | 0.74 ounces (21 grams) |
Figure 3: The Casio F-91W-3DG on a wrist, demonstrating its slim profile and comfortable fit.
Warranty and Support
Warranty Information
This Casio F-91W-3DG watch comes with a 2-year manufacturer's warranty. Please refer to the included warranty card for specific terms and conditions regarding coverage and service.
Customer Support
For any questions, technical assistance, or warranty claims, please contact Casio customer support or visit the official Casio website. Keep your purchase receipt and warranty card for future reference.
