Casio 2608, 2638, 2688 Timekeeping, Battery Power Indicator, Charging Precautions, Charging Guide, Charge Times, Setting the Time and Date Manually

Operation Guide 2608 2638 2688

Important!

•Storing the watch for long periods in an area where there is no light or wearing it in such a way that it is blocked from exposure to light can cause rechargeable battery power to run down. Be sure that the watch is normally exposed to bright light whenever possible.

•This watch employs a solar cell that converts light into electricity that charges a built- in rechargeable battery. Normally, the rechargeable battery should not need replacement, but after very long use over a number of years, the rechargeable battery may lose its ability to achieve a full charge. Should you notice problems with getting the rechargeable battery to a full charge, contact your dealer or CASIO distributor about having the rechargeable battery replaced.

•The rechargeable battery should be replaced with a CASIO-specified CTL1616 battery only. Other rechargeable batteries can cause damage to the watch.

•All data stored in memory is deleted, and the current time and all other settings return to their initial factory defaults whenever battery power drops to Level 4 and when you have the battery replaced.

•Turn on the watch’s Power Saving function and keep it in an area normally exposed to bright light when storing it for long periods. This helps to keep the rechargeable battery from going dead.

Battery Power Indicator

The battery power indicator on the display shows you the current status of the rechargeable battery’s power.

	Level	Battery Power Indicator			Function Status
Battery power	1	Module 2608	2638	2688	All functions enabled.
indicator
	2				All functions enabled.
	3				Beeper tone, backlight,
					calibration signal
					reception, display, and
		Charge Soon Alert			buttons are disabled.
Recover
indicator	4				All functions, including
					timekeeping, are
					disabled.

•The Level 3 charge warning indicator tells you that battery power is very low, and that exposure to bright light for charging is required as soon as possible.

•At Level 4, all functions are disabled and settings return to their initial factory defaults. Functions are enabled once again after the rechargeable battery is charged, but you need to set the time and date after the battery reaches Level 3 from Level 4. You will not be able to configure any of the other settings until the battery reaches Level 2 after dropping to Level 4.

•Leaving the watch in direct sunlight or some other very strong light source can cause the battery power indicator to temporarily show a reading that is actually higher than the battery level. The correct battery power indicator should appear after a few minutes.

•If you use the backlight or the alarms a number of times during a short period, the

recover indicator (R /RECOVER ) appears on the display and the following operations become disabled until battery power recovers.

Backlight Beeper tone Calibration reception

After some time, battery power will recover and the recover indicator (R / RECOVER ) will disappear, indicating that the above functions are enabled again.

Charging Precautions

Certain charging conditions can cause the watch to become very hot. Avoid leaving the watch in the areas described below whenever charging its rechargeable battery. Also note that allowing the watch to become very hot can cause its liquid crystal display to black out. The appearance of the LCD should become normal again when the watch returns to a lower temperature.

Warning!

Leaving the watch in bright light to charge its rechargeable battery can cause it to become quite hot. Take care when handling the watch to avoid burn injury. The watch can become particularly hot when exposed to the following conditions for long periods.

•On the dashboard of a car parked in direct sunlight

•Too close to an incandescent lamp

•Under direct sunlight

Charging Guide

After a full charge, timekeeping remains enabled for up to about six months, while the watch is used under the conditions described below.

Operating Conditions

•Watch is not exposed to light

•Display on 18 hours per day, sleep state 6 hours per day

•1 backlight operation (1.5 seconds) per day

•10 seconds of alarm operation per day

•4 times calibration reception per day

Charge Times

Exposing the watch to light for the periods shown below each day restores the power used by the above operating conditions.

Exposure Level (Brightness)	Approximate
	Exposure Time
Outdoor Sunlight (50,000 lux)	5 minutes
Sunlight Through a Window (10,000 lux)	24 minutes
Daylight Through a Window on a Cloudy Day (5,000 lux)	48 minutes
Indoor Fluorescent Lighting (500 lux)	8 hours
• Stable operation is promoted by frequent charging.

Recovery Times

The table below shows the amount exposure that is required to take the battery from one level to the next.

Exposure Level	Approximate Exposure Time
(Brightness)	Level 4	Level 3		Level 2		Level 1
			▲		▲		▲
Outdoor Sunlight	1 hour			14 hours		3 hours
(50,000 lux)
Sunlight Through a	3 hours			70 hours		14 hours
Window (10,000 lux)
Daylight Through a	5 hours			143 hours		28 hours
Window on a Cloudy
Day (5,000 lux)
Indoor Fluorescent	57 hours			------------		------------
Lighting (500 lux)

•The above exposure time values are all for reference only. Actual required exposure times depend on lighting conditions.

Timekeeping

Use the Timekeeping Mode to set and view the current time and date. This section also explains how to manually set the current date and time.

•The watch is equipped with a Time Recorder feature that lets you record the current Home City time (month, day, hour, minutes, seconds, and DST on/off setting) with the touch of a button. See “To record a Time Recorder time” for more information.

•All of the operations in this section are performed in the Timekeeping Mode, which you can enter by pressing C.

PM	Day of week	Receive time
indicator
	Press D.
	▲	▲
	Month – Day	Receive date
	Hour : Minutes Seconds	Last Signal Screen

Setting the Time and Date Manually

Make sure you select your Home City code before you change the current time and date settings. World Time Mode times are all displayed in accordance with the Timekeeping Mode settings. Because of this, World Time Mode times will not be correct if you do not select the proper Home City code before setting the time and date in the Timekeeping Mode.

To set the current time and date manually

1. In the Timekeeping Mode, hold down Auntil the city

City code code starts to flash, which indicates the setting screen. 2. Press Aor Cto move the flashing in the sequence

shown below to select other settings.

			Press C.	/ Press A.
City/Auto receive			C		Auto
		City Code		DST
					Receive
Settings
	A
	12/24-Hour		C		Hour	Minutes
Time/Date/Power	Format		Seconds
Saving Settings	Power Saving
			Day		Month	Year
	on/off

3.When the setting you want to change is flashing, use B and/or Dto change it as described below.

City/Auto Receive Settings

Screen:	To do this:	Do this:
	Change the city code	Use D (east) and B (west).
	Cycle between Daylight Saving Time	Press D.
	(ON), Standard Time (OFF), and
	Auto DST (AUTO)
	Toggle between auto receive on	Press D.
	(ON) and off (OFF)

•See “City Code Table” for a complete list of available city codes.

Time/Date/Power Saving Settings

Screen:	To do this:	Do this:
	Toggle between 12-hour (12H) and	Press D.
	24-hour (24H) timekeeping
	Reset the seconds to 00	Press D.
	Change the hour or minutes	Use D (+) and B (–).
	Change the month, day, or year	Use D (+) and B (–).
	Toggle the Power Saving on (ON)	Press D.

and off (OFF)

4. Use Ato exit the setting screen.

•If a City/Auto Receive Setting screen is displayed, press Atwice.

•If a Time/Date/Power Saving Setting screen is displayed, press Aonce.

Note

•Auto DST (AUTO) can be selected only while HNL, ANC, LAX, DEN, CHI, or NYC is selected as the Home City code. For more information, see “Daylight Saving Time (DST)” below.

•The auto receive setting is used for time calibration signal reception only. See “About Auto Receive” for details.

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