Casio WVA-420 Watch User Manual

Battery

The battery initially installed is for testing purposes and may have a shorter lifespan than a standard battery. If you notice signs of low power (dim display, no backlight), replace the battery at an authorized CASIO dealer or distributor.

Water Resistance

Watches are classified by water resistance levels (I to V). Refer to the table below to understand the usage rules for your watch.

Notes for relevant sections:

• Level I: The watch is not water-resistant. Avoid all moisture.
• Level III: If exposed to salt water, rinse thoroughly with fresh water and dry.
• Level IV: If exposed to salt water, rinse thoroughly with fresh water and dry.
• Level V: Can be used for scuba diving (excluding depths requiring helium-oxygen mixtures).

ATTENTION!!! For all categories of watches, it is forbidden to:

• Press buttons underwater.
• Set hands underwater.
• Unscrew the crown underwater.

Some water-resistant watches have leather straps. Do not wear these watches while swimming or engaging in any activity where the strap may be submerged.

For Watches with Polymer Straps:

• A white powdery substance may appear on the strap. This is harmless and can be removed by wiping with a soft cloth.
• Sweat or moisture, or storage in high humidity, can damage, tear, or crack the strap. Wipe the strap frequently with a soft cloth to prolong its life.

For Watches with Fluorescent Cases and Straps:

• Prolonged exposure to direct sunlight can cause the fluorescent color to fade.
• Prolonged contact with moisture can also cause fading. Wipe off any moisture promptly.
• Rubbing a fluorescent surface can transfer the color to other surfaces.

Setting Home City Code

1. In Timekeeping Mode, press and hold Button [A] until the signal transmission indicator (A/T, MSF, DCF) flashes, indicating setup mode.
2. If the "A/T" indicator does not appear, press Button [D].
3. Press Button [C] to cycle through city codes.
4. Use Buttons [B] and [D] to select your home city code.
5. Press Button [A] twice to exit setup.

Calibration Signal

The watch receives calibration signals to update the time. Signal transmitters are located in Germany (25km from Frankfurt) and Rugby, England, with a range of approximately 1000km. Signal strength can be affected by distance, terrain, and atmospheric conditions, as well as nearby electronic devices (TVs, computers), tunnels, airports, train stations, busy roads, radio stations, and static electricity.

There are two types of signal reception:

• Auto-Calibration: The watch automatically attempts to receive the signal five times daily and adjusts the time.
• Forced Calibration: You manually initiate signal reception by pressing a button.

To perform Forced Calibration:

1. Position the watch horizontally.
2. In Timekeeping Mode, press and hold Button [D] for 2 seconds until a beep sounds and the "RC" indicator flashes, starting reception.
3. Reception lasts 2 to 7 minutes. Do not move the watch during this period.
4. After reception, the display shows the last received signal data.
5. Press Button [D] to stop reception and return to Timekeeping Mode.

If reception fails, the "ERR" indicator will appear for 1-2 minutes before returning to Timekeeping Mode. You can return to Timekeeping Mode by pressing Button [D].

Auto-Calibration: The watch attempts reception five times daily at 0:00, 1:00, 2:00, 3:00, and 4:00. An additional attempt may occur at 5:00 if previous attempts failed. Auto-calibration only occurs in Timekeeping or World Time modes.

Calibration Signal Indicator

This indicator shows the strength of the received signal. For best reception, position the watch optimally. It takes about 10 seconds for the indicator to stabilize. If the calibration indicator is not present, reception is not occurring; manually calibrate or check settings.

Enabling/Disabling Auto-Calibration Signal

1. In Timekeeping Mode, press and hold Button [A] until the city code flashes.
2. Press Button [C] three times to reach the auto-calibration setting.
3. If your home city does not support auto-calibration, "--" will appear.
4. Press Button [D] to toggle Auto-Calibration ON or OFF.
5. Press Button [A] twice to exit setup.

Timekeeping Mode Display

• Pressing Button [D] in Timekeeping Mode switches between current time/date and last calibration time.
• Pressing Button [A] switches the date display to show the calibration signal indicator and seconds, or the current time.

Setting Time and Date

1. In Timekeeping Mode, press and hold Button [A] until the city code flashes.
2. Press Buttons [A] and [C] to cycle through settings: [Signal Reception → City Code → Daylight Saving Time (DST) → Auto-Calibration → 12/24 Hour Format → Seconds → Hours → Minutes → Year → Month → Day → Power Saving Mode].
3. To set seconds: Press Button [D] to reset to 00. If seconds are 30-59, minutes increment. If 00-29, minutes remain unchanged.
4. Use Buttons [B] and [D] to adjust minutes, hours, etc.
5. Press Button [D] to switch between 12/24 hour format. "P" indicates PM in 12-hour format.
6. Use Buttons [D] and [B] to select city names.
7. Press Button [D] to enable/disable Daylight Saving Time (DST). Options: Auto-Switch ("A"), ON, OFF.
8. Press Button [D] to enable/disable Auto-Calibration.
9. Press Button [D] to enable/disable Power Saving Mode.
10. Press Button [B] to set backlight duration (1.5 seconds or 2.5 seconds).
11. Press Button [D] to select calibration signal reception type (A/T, MSF, DCF). Holding the button allows faster scrolling.
12. Day of the week is set automatically based on the date.
13. Date can be set from January 1, 2000, to December 31, 2099.
14. Press Button [A] to confirm settings and exit.

Backlight

Press Button [B] in any mode to activate the backlight. The watch uses an LED combined with a fluorescent coating for visibility in the dark. An audible signal may sound during illumination due to vibrating backlight elements; this is not a malfunction. Backlight may be difficult to see in direct sunlight. Frequent use of the backlight reduces battery life. You can set the backlight duration to 1.5 or 2.5 seconds by pressing Button [B] in Timekeeping Mode.

Setting an Alarm

1. In Alarm Mode, press Button [D] to select alarm type: AL1 → AL2 → AL3 → SIG (hourly signal).
2. Select the alarm type, then press and hold Button [A]. The hour digits will flash, and the alarm will be enabled.
3. Press Button [C] to cycle through setting Hours → Minutes → Hours.
4. Use Buttons [D] (increase) and [B] (decrease) to set the value. Holding the button allows faster adjustment.
5. The 12/24 hour format follows your current time setting. Be mindful of AM/PM in 12-hour format.
6. Press Button [A] to confirm and return to Alarm Mode.

Testing Alarm Sound

In Alarm Mode, press Button [D] to test the alarm sound.

Enabling/Disabling Alarm Sound

1. In Alarm Mode, press Button [D] to select the alarm type.
2. Press Button [A] to enable or disable the selected alarm. The "ALM" indicator appears when an alarm is active. The "SIG" indicator appears for the hourly signal.

Battery Power Indicator

If there is no indicator, the battery is fully discharged. Place the watch in a well-lit area.

Caution: Do not leave the watch in direct sunlight for extended periods, as this may cause malfunctions. If you frequently use the backlight or alarm, the "R" indicator may appear, signaling the need for recharging.

Battery Charging

After a full charge, normal operation lasts approximately 5 months under the following conditions:

• Watch not exposed to direct sunlight.
• 5 calibration signals received per day.
• Backlight used for 1.5 seconds per day.
• Alarm used for 10 seconds per day.

Daily exposure to light ensures continuous battery charging.

Approximate Exposure Time for Charging:

Time Required for Full Charge:

Enabling/Disabling Power Saving Mode

1. In Timekeeping Mode, press and hold Button [A] until the city code flashes.
2. Press Button [A] again.
3. Press Button [C] to select Power Saving Mode.
4. Press Button [D] to toggle Power Saving Mode ON or OFF.
5. Press Button [A] to exit setup.

The "PS" indicator appears when Power Saving Mode is active. The watch may enter sleep mode automatically. To wake it, place it in light or press any button.

• When Power Saving Mode is active, the display, alarm, auto-calibration, and analog timekeeping functions are affected as described above.