1. Introduction
This manual provides detailed instructions for the proper use and care of your G-Shock GMAS2100-1A watch. The GMAS2100-1A is a compact and lightweight timepiece featuring an octagonal bezel, a flat face, and a carbon core guard structure for enhanced durability. It is designed for robust performance and includes various timekeeping functions.
Image 1.1: Front view of the G-Shock GMAS2100-1A watch. This image shows the watch face with its octagonal bezel, analog hands, and digital display, highlighting the rose gold-tone hour markers and hands against the black dial.
2. Initial Setup
Upon first use or after a battery replacement, it is necessary to set the current time and date. Refer to the following steps:
- Time Zone Selection: In Timekeeping Mode, hold down the 'ADJUST' button (top left) until the city code starts to flash. Use the 'START' (bottom right) and 'LIGHT' (top right) buttons to select your desired home city code.
- Daylight Saving Time (DST): Press the 'MODE' button (bottom left) to toggle DST settings (ON/OFF).
- Time and Date Adjustment: Continue pressing the 'MODE' button to cycle through settings such as 12/24-hour format, seconds, hour, minute, year, month, and day. Use the 'START' and 'LIGHT' buttons to adjust the flashing value.
- Finalize Settings: Once all settings are configured, press the 'ADJUST' button to exit the setup screen. The analog hands will automatically adjust to match the digital time.
Image 2.1: Side view of the G-Shock GMAS2100-1A watch. This image provides a closer look at the watch's profile and the four operational buttons located on its sides.
3. Operating Instructions
Your GMAS2100-1A watch offers multiple modes and functions. Use the 'MODE' button (bottom left) to navigate between them.
3.1. Timekeeping Mode
This is the default mode, displaying the current time and date. The watch features both analog hands and a digital display. The Neobrite coating on the hands and markers provides visibility in low light, complemented by a Double LED light (Super Illuminator) for the face and digital display.
- Light Function: Press the 'LIGHT' button (top right) to illuminate the watch face and digital display. Illumination duration can be set to 1.5 or 3 seconds.
- Hand Shift Feature: If the analog hands obstruct the digital display, hold down the 'MODE' button for approximately two seconds to temporarily shift the hands away. Repeat the action to return them to normal timekeeping.
3.2. World Time Mode
View the current time in 31 time zones (48 cities + Coordinated Universal Time). In World Time Mode, use the 'START' and 'LIGHT' buttons to scroll through different city codes.
3.3. Stopwatch Mode
The stopwatch measures elapsed time, split times, and two finishes with 1/100-second accuracy for the first 60 minutes, then 1-second accuracy up to 24 hours.
- Start/Stop: Press the 'START' button.
- Reset: While stopped, press the 'ADJUST' button.
3.4. Countdown Timer Mode
Set a countdown from 1 second up to 24 hours. An alarm sounds when the countdown reaches zero.
- Set Timer: In Countdown Timer Mode, hold 'ADJUST' to enter setting mode. Use 'START' and 'LIGHT' to set the desired time. Press 'ADJUST' to confirm.
- Start/Stop: Press the 'START' button.
- Reset: While stopped, press the 'ADJUST' button.
3.5. Alarm Mode
The watch features 5 daily alarms and an hourly time signal. In Alarm Mode, use 'START' and 'LIGHT' to scroll through alarms (AL1-AL5, SIG). Hold 'ADJUST' to set an alarm time.
- Turn Alarm ON/OFF: Press 'START' to toggle the selected alarm or hourly time signal ON/OFF.
Image 3.1: Angled view of the G-Shock GMAS2100-1A watch. This perspective highlights the watch's overall design, including the textured strap and the integration of the octagonal bezel with the case.
4. Maintenance
Proper maintenance ensures the longevity and performance of your G-Shock watch.
- Cleaning: Wipe the watch with a soft, dry cloth. For resin bands and cases, use a soft brush with water and mild soap, then rinse thoroughly and dry. Avoid harsh chemicals.
- Water Resistance: The watch is 200-meter water resistant. It is suitable for showering, swimming, and shallow diving. Do not operate buttons underwater.
- Battery Replacement: The watch requires 1 LR44 battery. Battery life varies depending on usage. When the display becomes dim or functions become unreliable, it is time to replace the battery. It is recommended to have battery replacement performed by an authorized service center to ensure water resistance integrity.
- Temperature Exposure: Avoid exposing the watch to extreme temperatures, direct sunlight for prolonged periods, or strong magnetic fields.
5. Troubleshooting
If you encounter issues with your watch, refer to the following common solutions:
| Problem | Solution |
|---|---|
| Analog hands do not match digital time. | Perform a hand alignment correction. Refer to the full manual for detailed steps, or re-enter Timekeeping Mode setup and exit to trigger automatic hand adjustment. |
| Digital display is dim or blank. | The battery may be low. Replace the LR44 battery. |
| Buttons are unresponsive. | Ensure the watch is not in a mode that locks button operations. If submerged, dry the watch thoroughly before attempting to press buttons. If the issue persists, a reset may be required (consult service center). |
| Time is incorrect. | Verify the home city code and DST settings are correct in Timekeeping Mode. Adjust as necessary. |
6. Specifications
- Model Number: GMAS2100-1A
- Case/Bezel Material: Carbon/Resin
- Band Material: Resin
- Glass: Mineral Glass
- Water Resistance: 200 meters (20 BAR)
- Shock Resistance: Yes
- Light: Double LED light (Super Illuminator) for face and digital display, with selectable illumination duration (1.5 or 3 seconds) and afterglow.
- World Time: 31 time zones (48 cities + UTC), DST on/off.
- Stopwatch: 1/100-second (first 60 minutes), 1-second (after 60 minutes), measuring capacity: 23:59'59.99''.
- Countdown Timer: Measuring unit: 1 second, countdown range: 24 hours, countdown start time setting range: 1 second to 24 hours (1-second increments, 1-minute increments, 1-hour increments).
- Alarms: 5 daily alarms, hourly time signal.
- Calendar: Full auto-calendar (to year 2099).
- Other Features: 12/24-hour format, Button operation tone on/off, Hand shift feature, Regular timekeeping (analog: 2 hands; digital: hour, minute, second, pm, month, date, day).
- Case Size (H×W×D): 46.2 × 42.9 × 11.2 mm
- Weight: Approximately 41g
- Battery: 1 x LR44 (approx. 3 years battery life)
Image 6.1: A collection of G-Shock GMAS2100 series watches in different color variations. This image illustrates the compact design and aesthetic versatility of the model.
7. Warranty and Support
Your G-Shock watch is covered by a manufacturer's warranty against defects in materials and workmanship. For specific warranty terms, duration, and service procedures, please refer to the warranty card included with your purchase or visit the official G-Shock website.
For technical support, repairs, or inquiries, please contact G-Shock customer service or an authorized service center. Contact information can typically be found on the official G-Shock website or in the documentation provided with your watch.
