Casio 2760, 2761 Power Supply, Reference, About the Auto Light Switch, Battery Power Levels, Charging Precautions, Charging Guide, Recovery Times, Auto Return Features

Operation Guide 2760 2761

About the Auto Light Switch

Turning on the auto light switch causes the face to illuminate, whenever you position your wrist as described below in any mode. Note that this watch features a “Full Auto LED Light”, so the auto light switch operates only when available light is below a certain level. It does not illuminate the face under bright light.

Moving the watch to a position that is parallel to the ground and then tilting it towards you more than 40 degrees causes illumination to turn on.

•Wear the watch on the outside of your wrist.

Parallel to	More than
ground	40°

Warning!

•Always make sure you are in a safe place whenever you are reading the face of the watch using the auto light switch. Be especially careful when running or engaged in any other activity that can result in accident or injury. Also take care that sudden illumination by the auto light switch does not surprise or distract others around you.

•When you are wearing the watch, make sure that its auto light switch is turned off before riding on a bicycle or operating a motorcycle or any other motor vehicle. Sudden and unintended operation of the auto light switch can create a distraction, which can result in a traffic accident and serious personal injury.

To turn the auto light switch on and off

In any mode (except when a setting screen is on the display), hold down D for about

two seconds to toggle the auto light switch on ( displayed) and off ( not displayed).

•The auto light switch on indicator ( ) is on the display in all modes while the auto light switch is turned on.

Power Supply

This watch is equipped with a solar cell and a special rechargeable battery (secondary battery) that is charged by the electrical power produced by the solar cell. The illustration shown below shows how you should position the watch for charging.

Example: Orient the watch so its face is
pointing at a light source.	Solar cell
• The illustration shows how to position
a watch with a resin band.
• Note that charging efficiency drops
when any part of the solar cell is
blocked by clothing, etc.

•Normally, you should try to keep the watch outside of your sleeve as much

as possible. Charging is significantly reduced if the face is only partially covered.

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. Make sure that the watch is normally exposed to bright light whenever possible.

•This watch uses a special rechargeable battery to store power produced by the solar cell, so regular battery replacement is not required. However, after very long use, the rechargeable battery may lose its ability to achieve a full charge. If you experience problems getting the special rechargeable battery to fully charge, contact your dealer or CASIO distributor about having it replaced.

•Never try to remove or replace the watch’s special battery yourself. Use of the wrong type of battery can damage 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 Levels

The battery level dial and digital display show you the current level of the rechargeable battery’s power. The digital display also shows a recover indicator, which lets you know when there is a large load being placed on the battery.

Battery level dial		Level	Dial and				Function Status
			Digital Display
		1					All functions enabled.
l ll
l	l
l	ll	2					All functions enabled.
l
ll
		3	ll	l l l		ll	Except for internal timekeeping
			l			l	and the C indicator, all functions
			l			l
			l	l		l
			A		l l l		and display indicators are
Recover indicator			(Charge soon alert)				disabled.
		4					All functions disabled.

•The battery level dial shows the battery power level in all modes except for the Stopwatch Mode. In the Stopwatch Mode, the battery level dial indicates elapsed minutes.

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

•When battery power is at Level 3, analog hand movement and time calibration signal reception are disabled.

•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 digital time and date, after the battery reaches Level 3 from Level 4. You will not be able to set any of the other settings until the battery reaches Level 2 after dropping to Level 4.

•Display indicators reappear as soon as the battery is charged from Level 4 to Level

3.

•Leaving the watch exposed to direct sunlight or some other very strong light source can cause the battery level dial to temporarily show a reading that is higher than the actual battery level. The correct battery level should be indicated after a few minutes.

•If you use the illumination or alarms a number of times during a short period, the recover indicator (R) appears on the display and the following operations become disabled until battery power recovers.

Illumination; Beeper tone; Coordination between digital and analog timekeeping; Time calibration signal reception

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

•If the recover indicator appears frequently, it probably means that remaining battery power is low. Leave the watch in bright light to allow it to charge.

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 five months.

•The following table shows the amount of time the watch needs to be exposed to light each day in order to generate enough power for normal daily operations.

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	48 minutes
(5,000 lux)
Indoor Fluorescent Lighting (500 lux)	8 hours

•Since these are the specs, we can include all the technical details.

•Watch is not exposed to light

•Internal timekeeping

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

•1 light operation (1.5 seconds) per day

•10 seconds of alarm operation per day

•5 times calibration reception per day

•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 (50,000 lux)	1 hour				14 hours			4 hours
Sunlight Through a Window	3 hours				71 hours			20 hours
(10,000 lux)
Daylight Through a Window	5 hours					– – –
on a Cloudy Day (5,000 lux)
Indoor Fluorescent Lighting	49 hours					– – –
(500 lux)

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

Reference

This section contains more detailed and technical information about watch operation. It also contains important precautions and notes about the various features and functions of this watch.

Auto Return Features

•If you leave the watch in the Recall, Alarm (except for the target alarm countdown screen), or Hand Setting Mode for two or three minutes without performing any operation, it automatically returns to the Timekeeping Mode.

•If you leave a screen with flashing digits on the display for two or three minutes without performing any operation, the watch automatically exits the setting screen.

Scrolling

The B and D buttons are used in various modes and setting screens to scroll through data on the display. In most cases, holding down these buttons during a scroll operation scrolls through the data at high speed.

Initial Screens

When you enter the Dual Time or Alarm Mode, the data you were viewing when you last exited the mode appears first.

Radio-controlled Timekeeping Precautions

•Strong electrostatic charge can result in the wrong time being set.

•Even when the watch is within the reception range of the transmitter, signal reception will be impossible if the signal is blocked by mountains or other geological formations between the watch and signal source.

•Signal reception is affected by weather, atmospheric conditions, and seasonal changes.

•The time calibration signal bounces off the ionosphere. Because of this, such factors as changes in the reflectivity of the ionosphere, as well as movement of the ionosphere to higher altitudes due to seasonal atmospheric changes or the time of day may change the reception range of the signal and make reception temporarily impossible.

•Even if the time calibration signal is received properly, certain conditions can cause the time setting to be off by up to one second.

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