Casio module 5425: user manual and setup (GBM-2100A)

The module number is engraved on the case back, usually in a small rectangle next to the other markings. If it says 5425, this guide applies to your watch. The Casio manual covers modules 5146 and 5425 together. The difference is that only module 5146 has a graphic that moves along with the seconds count.

Which watches use module 5425

Module 5425 is a combination analog-digital module. The hands show the time, and the digital display shows the date, seconds and the additional functions. The analog time is synchronized with the digital time and is adjusted automatically whenever the digital time changes. The watch also has a separate speed hand that works with the stopwatch.

• GBM-2100A-1A2ER – Casio G-Shock GBM-2100A-1A2ER

Buttons and modes

The watch has five modes: Timekeeping (time and date), Stopwatch, Countdown Timer, Alarm and World Time. You change modes with the mode button. Each press moves the watch to the next mode. In every mode except the setting mode, the light button illuminates the display. The 12-hour or 24-hour format selected in Timekeeping Mode applies in all other modes.

In Timekeeping Mode the digital display shows the city, the day of the week, the time and the seconds. One button switches the display between the Home City date and the Home City time. The date screen shows the month, day and seconds.

How to set the time and date

1. Enter Timekeeping Mode.
2. Hold down the setting button for about three seconds. The current city code starts to flash in the upper part of the display. This is the setting mode.
3. Select your Home City with the east and west buttons. Do this before any other setting. The full list of city codes is at the end of the manual.
4. Use the mode button to move through the settings in this order: city code, daylight saving time (DST), seconds, hour, minutes, year, month, day, 12/24-hour format, illumination duration.
5. When the seconds are flashing, press the plus button to reset them to 00.
6. When the hour, minutes, year, month or day is flashing, use the plus and minus buttons to change it.
7. When DST is flashing, press the plus button to toggle between daylight saving time (on) and standard time (OFF).
8. When the format is flashing, press the plus button to select 12H or 24H.
9. When the illumination setting is flashing, the same button toggles between 1.5 seconds (LT1) and three seconds (LT3).
10. Press the setting button to exit the setting mode.

The day of the week is shown automatically according to the year, month and day you set. If the hands do not match the digital time, use the home position correction procedure described below.

Daylight saving time and 12/24-hour format

Daylight saving time (DST) moves the time one hour ahead of standard time. Not all countries and regions use it. To change it, hold down the setting button for about three seconds in Timekeeping Mode. Then press the mode button once to reach the DST screen. The plus button toggles between on and OFF. The factory setting is OFF. When daylight saving time is on, a DST indicator appears on the display. Exit with the setting button.

In 12-hour format the P indicator is shown from noon to 11:59 p.m. From midnight to 11:59 a.m. there is no indicator. In 24-hour format the time runs from 0:00 to 23:59 with no indicator.

Stopwatch

The Stopwatch measures elapsed time, lap time and split time. Its range is 99 hours, 59 minutes and 59.999 seconds. When the limit is reached, measurement starts again from zero. The Stopwatch keeps running after you leave the mode. In this case the segments in the upper part of the display count the seconds of the current time. This tells you that measurement is still in progress.

If you set a distance, the watch calculates and shows speed. The value can be in kilometers, miles or another unit of your choice. At 0.0 no speed is calculated. For laps you can set the length of one lap or the total distance. For split times only the total distance is set, so the speeds are not true intermediate values. Speed is shown by the speed hand up to 100 units, by the segments for hundreds and by an indicator for 1000.

To set a distance, the Stopwatch must be stopped and reset. Reset it with the setting button. Then hold down the same button for about three seconds until the value flashes in the lower part of the display. Before any button operation, check that the speed hand is not moving.

Countdown Timer

Countdown Timer Mode counts down from a set start time. In its settings you set the start time and auto-repeat. The detailed steps are on pages E-25 to E-28 of the manual.

World Time

In World Time Mode you see the current time in another time zone. For each city code you can toggle between standard time and daylight saving time. The manual also describes how to swap the Home City and the World Time city.

Alarms and Hourly Time Signal

Alarm Mode lets you set an alarm time and turn each alarm on or off. Separately, you can turn the Hourly Time Signal on or off. It sounds at the top of every hour.

Illumination

The display is illuminated manually with the light button in every mode except the setting mode. The duration is 1.5 seconds (LT1) or three seconds (LT3) and is set in the time settings. There is also an auto light switch, which is turned on and off by the procedure described in the manual. When the battery is low, the auto light switch turns itself off about six hours after it is turned on. If you want to use it again, repeat the procedure for turning it on.

Hand position correction

If the hour and minute hands do not match the digital time, use the Hand Home Position Correction function. In it you check whether the hands are in the correct home positions and correct them if needed. The full procedure is on page E-42 of the manual.

The original Casio manual (PDF)

Casio module 5425 manual (PDF, English) is the official Casio document for modules 5146 and 5425. It contains all the steps, the city code table and the specifications.

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