MA0309-EB
Operation Guide 2790
Getting Acquainted
Congratulations upon your selection of this CASIO watch. To get the most out of your
purchase, be sure to carefully read this manual and keep it on hand for later reference
when necessary.
Expose the watch to bright light to charge its battery before using it.
You can use this watch even as its battery is being charged by exposure to bright
light.
• Be sure to read “Battery” for important information you need to know when
exposing the watch to bright light.
If the digital display of the watch is blank...
If the Power Saving on indicator (PS) is on the display
(either flashing or not flashing), it means that the
display is blank because the watch’s Power Saving
function has turned off the display to conserve
power. Power Saving automatically turns off the display
and enters a sleep state whenever your watch is left for
a certain period where it is dark. If the watch is kept in
the dark for a longer period, the analog hands will also
stop moving after a few days.
• The initial factory default setting is Power Saving on.
• The watch recovers from the sleep state if you move it
to a well-lit area, if you press any button, or if you
angle the watch towards your face for reading.
• See “Power Saving Function” for more
information.
About This Manual
• Button operations are indicated using the letters shown
in the illustration.
• For the sake of simplicity, the sample displays in this
manual do not show the analog hands of the watch.
• Each section of this manual provides you with the
information you need to perform operations in each
mode. Further details and technical information can be
found in the “Reference” section.
General Guide
• Press B to change from mode to mode.
• In any mode, press L to illuminate the display.
Timekeeping Mode
Alarm Mode
Press
Stopwatch Mode
Dual Time Mode
Hand Setting Mode
.
Timekeeping
This watch features both digital and analog timekeeping. Changing the digital time
setting causes the analog setting to be adjusted automatically to match the digital time.
• Whenever you need to adjust both the digital and the analog time settings, make
sure you adjust the digital setting first.
• In the Timekeeping Mode, press A to toggle the display between the date screen
and the time screen.
3. When the setting you want to change is flashing, use C and L to change it as
described below.
Screen
36
P10:08
Time Screen
Date Screen
2003
6-30
Minute hand
To do this:
Reset the seconds to 00
Toggle illumination duration between three seconds
(3" displayed) and one second (3" not displayed)
Change the hour or minutes
Change the year
Change the month or day
Do this:
Press C.
Press L.
Press C (+).
Hour : Minutes
Hour hand
Press
.
Month – Day
PM indicator
Day of week
Seconds
Seconds
Digital Time and Date
Use the Timekeeping Mode to set and view a digital display of the current time and
date. When setting the digital time, you can also specify the illumination duration.
To set the digital time and date
1. In the Timekeeping Mode, hold down A until the
seconds start to flash, which indicates the setting
screen.
• The hour hand and minute hand of the watch do not
move while the setting screen is on the display.
2. Press B to move the flashing in the sequence shown
below to select the other settings.
Seconds/Illumination duration
Day
Month
Hour
Minutes
4. Press A to exit the setting screen.
• When you use the above procedure to set the digital display time, the hands of the
analog timepiece normally adjust according to your setting.
• For more information about illumination duration, see “Display Illumination”.
• Resetting the seconds to 00 while the current count is in the range of 30 to 59
causes the minutes to be increased by 1. In the range of 00 to 29, the seconds are
reset to 00 without changing the minutes.
• The day of the week is automatically displayed in accordance with the date (year,
month, and day) settings.
• The year can be set in the range of 2000 to 2099.
• The watch’s built-in full automatic calendar makes allowances for different month
lengths and leap years. Once you set the date, there should be no reason to change
it except after you have the watch’s battery replaced.
To toggle between 12-hour and 24-hour timekeeping
In the Timekeeping Mode, press C to toggle between 12-hour timekeeping (indicated
by A or P on the display), or 24-hour timekeeping.
• With the 12-hour format, the P (PM) indicator appears on the display for times in the
range of noon to 11:59 p.m. and the A (AM) indicator appears for times in the range
of midnight to 11:59 a.m.
• With the 24-hour format, times are displayed in the range of 0:00 to 23:59, without
any indicator.
• The 12-hour/24-hour timekeeping format you select in the Timekeeping Mode is
applied in all modes.
Year
1
Operation Guide 2790
Stopwatch
Analog Timekeeping
Minutes
Seconds
The analog time of this watch is synchronized with the digital time. The analog time
setting is adjusted automatically whenever you change the digital time.
Note
• After you manually change the digital time setting, the hands of the analog timepiece
move clockwise to adjust to the new setting. If the analog time does not match the
digital time for any reason, use the procedure described under “To adjust the analog
time” to match the analog setting to the digital setting.
• Alarms, the Hourly Time Signal, and the display illumination are all disabled while
the analog hands are moving.
• Whenever you need to manually adjust both the digital and the analog time settings,
make sure you adjust the digital setting first.
• Depending on how much the hands have to move in order to adjust to the digital
time, it may take some time before the analog hands stop moving.
1/100 second
Mode indicator
To measure times with the stopwatch
Elapsed time
Start
To adjust the analog time
1. In the Timekeeping Mode, press B four times to enter
the Hand Setting Mode.
2. Hold down A until the current digital time starts to
flash, which indicates the analog setting screen.
• Note that you will not be able to change to the setting
screen if the analog hands are moving because the
watch is automatically adjusting the analog time to
match the digital time. If this happens, wait until the
hands stop moving.
• The hour hand and minute hand of the watch do not
move while the setting screen is on the display.
3. Press C to advance the analog time setting by
20 seconds.
• Holding down C advances the analog time setting at
high speed.
• If you need to advance the analog time a long way, press C and L at the same
time. This locks the high speed hand movement, so you can release the two
buttons. High-speed hand movement continues until you press any button. It will
also stop automatically after the time advances 12 hours or if an alarm (daily
alarm or Hourly Time Signal) starts to sound.
4. Press A to exit the setting screen.
• To return to the Timekeeping Mode, press B.
Stop
When the daily alarm is turned on, the alarm tone sounds
when the alarm time is reached.
You can also turn on an Hourly Time Signal that causes
the watch to beep twice every hour on the hour.
• Alarm setting (and Hourly Time Signal setting) is
available in the Alarm Mode, which you enter by
pressing B.
The alarm tone sounds at the preset time for 10 seconds,
regardless of the mode the watch is in.
• Note that the alarm does not sound while the analog
hands are in motion to adjust in accordance with a
change made to the digital time setting in the
Timekeeping Mode.
To set an alarm time
1. In the Alarm Mode, hold down A until the hour setting
starts to flash, which indicates the setting screen.
• This operation automatically turns on the alarm.
2. Press B to move the flashing between the hour and
minutes.
3. While a setting is flashing, use C to increase it.
• With the 12-hour format, set the time correctly as a.m.
(A indicator) or p.m. (P indicator).
4. Press A to exit the setting screen.
To stop the alarm tone after it starts to sound
Press any button.
Alarm On Indicator/Hourly Time Signal On Indicator
Hourly time signal
on indicator
Both off
Daily alarm
only
Hourly Time
Signal only
• The alarm on ( ) indicator flashes while the alarm is
sounding.
• The alarm on ( ) indicator and Hourly Time Signal on
( ) indicator are displayed in all modes.
To test the alarm
In the Alarm Mode, hold down C to sound the alarm.
Clear
Dual Time Mode lets you keep track of a time in a different time zone.
• In the Dual Time Mode, the seconds count is synchronized with the seconds count
of the current digital time.
Hour : Minutes
To set the Dual Time
1. Press B to enter the Dual Time Mode.
2. Hold down A until the hour setting starts to flash,
which indicates the setting screen.
3. Press B to move the flashing between the hour and
minutes settings.
4. Press C to increase the setting.
5. Press A to exit the setting screen.
Seconds
Mode indicator
Display Illumination
An LED (light-emitting diode) and a light guide panel
illuminate the display for easy reading in the dark. The
watch’s auto light switch automatically turns on display
illumination when you angle the watch for reading in the
dark.
• The auto light switch must be turned on (indicated by
the auto light switch indicator) for it to operate.
• See “Illumination Precautions” for more important
information.
Three-second
indicator
To illuminate the display
In any mode, press L to turn on illumination.
• The above operation turns on illumination regardless of the current auto light switch
setting.
• You can use the procedure below to select either one second or three seconds as
the illumination duration. When you press L, the illumination will remain on for
about one second or three seconds, depending on the current illumination duration
setting.
To specify the illumination duration
1. In the Timekeeping Mode, hold down A until the seconds start to flash, which
indicates the setting screen.
2. While the seconds are flashing, press L to toggle the illumination duration
between three seconds (3" displayed) and one second (3" not displayed).
3. Press A to exit the setting screen.
• When the three-second setting is selected, the three-second (3") indicator remains
on the display in all modes.
About the Auto Light Switch
To turn the Daily Alarm and Hourly Time Signal on and off
In the Alarm Mode, press C to cycle through the on and
Alarm on indicator
off settings as shown below.
Both on
Stop
Auto light switch indicator
Alarm Operation
Mode indicator
Re-start
Dual Time
Alarm
Alarm time
(Hour : Minutes)
The stopwatch lets you measure elapsed time.
• The display range of the stopwatch is 59 minutes,
59.99 seconds.
• The stopwatch continues to run, restarting from zero
after it reaches its limit, until you stop it.
• The stopwatch measurement operation continues even
if you exit the Stopwatch Mode.
• All of the operations in this section are performed in the
Stopwatch Mode, which you enter by pressing B.
While the auto light switch is enabled, illumination turns on for about one second or
three seconds, whenever you position your wrist as described below in any mode.
Note that this watch features a “Full Auto Light,” so the auto light switch operates only
when available light is below a certain level. Illumination does not turn on under bright
light.
• Be sure to wear the watch on the outside of your wrist while using the auto light
switch.
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.
Parallel to ground
More than 40°
Warning!
• Always make sure you are in a safe place whenever you are reading 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 the Timekeeping Mode, hold down L for about two seconds to toggle the auto light
switch on (
displayed) or off (
not displayed).
• The auto light switch is automatically turned off whenever battery power is at Level
3. After battery power recovers to Level 2, you will have to perform the above
procedure to turn the auto light switch back on again.
• The auto light switch indicator (
) is on the display in all modes while the auto
light switch is turned on.
2
Operation Guide 2790
Battery
This watch is equipped with a solar cell and a 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
• Note that charging efficiency
drops when any part of the
solar cell is blocked by clothing,
etc.
• The illustration shows how to
position a watch with a resin
band.
• 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
• Stable operation is promoted by frequent charging.
Recovery Times
The table below shows the amount of exposure that is required to take the battery
from one level to the next.
Exposure Level
(Brightness)
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 bright 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, which 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 ML2016
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.
Approximate Exposure Time
Level 4
Level 3
Level 2
Outdoor Sunlight (50,000 lux)
Sunlight Through a Window
(10,000 lux)
Daylight Through a Window on a
Cloudy Day (5,000 lux)
Battery power indicator
Battery Power
indicator
Power Saving on
indicator
Function Status
(Charge Soon Alert)
4
Beeper tone, display
illumination, display, and
buttons are disabled. Though
the hands of the watch do not
move, time continues to be
kept internally.
All functions, including
timekeeping, are disabled.
• If the MID indicator starts to flash a few minutes after the display is illuminated or
after the beeper sounds, it means that the battery level is about to go from Level 2
to Level 3. If this happens, avoid using display illumination and the beeper, and
expose the watch to bright light to charge its battery.
• The flashing LO 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.
• 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 (indicated by flashing LO C indicator) from Level 4. You will not be able to
set any of the other settings until the battery reaches Level 2 (no LO C indicator)
after dropping to Level 4. When the battery returns to Level 2, the watch will
automatically adjust the analog time setting to match the digital time.
• 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 higher than
the actual battery level. The correct battery power indicator should appear after a
few minutes.
• If you use illumination or any of the alarm functions a number of times during a short
period, the recover (R) indicator appears on the display and the following operations
become disabled until battery power recovers.
Illumination; Beeper tone
Manual adjustment of the analog time in the Hand Setting Mode
After some time, battery power will recover and the recover (R) indicator 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 11 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)
Outdoor Sunlight (50,000 lux)
Sunlight Through a Window (10,000 lux)
Daylight Through a Window on a Cloudy Day (5,000 lux)
Indoor Fluorescent Lighting (500 lux)
–––
202 hours
189 hours
Power Saving Function
When turned on, the Power Saving function automatically
puts the watch into a sleep state whenever it is left in an
area where it is dark while the Timekeeping Mode or Dual
Time Mode is selected.
• The watch does not enter the sleep state while the
Stopwatch Mode is selected.
• The watch does not enter the sleep state while the
Alarm Mode or Hand Setting Mode is selected.
However, if you leave the watch in either of these
modes, it will automatically revert to the Timekeeping
Mode after a preset amount of time. After that it will be
able to enter the sleep state.
or
3
19 hours
93 hours
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.
All functions enabled.
2
20 hours
100 hours
Reference
All functions enabled.
1
46 hours
230 hours
• The above exposure time values are all for reference only. Actual required exposure
times depend on lighting conditions.
Battery Power Indicator
The battery power indicator on the display shows you the current status of the
rechargeable battery’s power.
Level
Level 1
• The table below shows how watch functions are affected by the Power Saving
function.
Elapsed Time in
Dark
About one hour
6 or 7 days
Display
Blank, with
PS flashing
Blank, with
PS not flashing
Operation
• Display is off.
• All functions and analog timekeeping are
enabled.
• Timekeeping is maintained.
• Display is off.
• Beeper is disabled.
• Analog timekeeping is disabled, with
hands positioned at 12 o’clock.
• Digital timekeeping is maintained.
• Wearing the watch inside the sleeve of clothing can cause it to enter the sleep state.
• The watch will not enter the sleep state between 6:00 AM and 9:59 PM. If the watch
is already in the sleep state when 6:00 AM arrives, however, it will remain in the
sleep state.
To recover from the sleep state
Perform any one of the following operations.
• Move the watch to a well-lit area.
• Press any button.
• Angle the watch towards your face for reading.
To turn Power Saving on and off
In the Timekeeping Mode, hold down C for about two
seconds to toggle Power Saving on (PS indicator
displayed) and off (PS indicator not displayed).
• Note that pressing C also toggles between 12-hour
timekeeping and 24-hour timekeeping.
• The Power Saving on indicator (PS) is on the display in
all modes while the Power Saving is turned on.
Auto return features
• If you leave a screen with flashing digits for two or three minutes without performing
any operation, the watch automatically saves anything you have input up to that
point and exits the setting screen.
• The watch automatically returns to the Timekeeping Mode if you do not perform any
button operation for two or three minutes in the Alarm or Hand Setting Mode.
Scrolling
The C button is used to scroll through setting screen data on the display. Holding
down this button during a scroll operation scrolls through the data at high speed.
Illumination Precautions
• The illumination provided by the light may be hard to see when viewed under direct
sunlight.
• Illumination automatically turns off whenever an alarm sounds.
• Frequent use of the light shortens the battery operating time.
• Note that illumination is disabled while the analog hands are in motion to adjust in
accordance with a change made to the digital time setting in the Timekeeping Mode.
Approximate
Exposure Time
5 minutes
24 minutes
48 minutes
8 hours
3
Operation Guide 2790
Auto light switch precautions
• The auto light switch is automatically turned off
whenever battery power is at Level 3.
More than 15 degrees
• Avoid wearing the watch on the inside of your wrist.
too high
Doing so causes the auto light switch to operate when it
is not needed, which shortens battery operating time. If
you want to wear the watch on the inside of your wrist,
turn off the auto light switch feature.
• Illumination may not turn on if the face of the watch is
more than 15 degrees above or below parallel. Make
sure that the back of your hand is parallel to the ground.
• Illumination turns off in about one second or three
seconds, even if you keep the watch pointed towards
your face.
• Static electricity or magnetic force can interfere with proper operation of the auto
light switch. If illumination does not turn on, try moving the watch back to the starting
position (parallel with the ground) and then tilt it back towards you again. If this does
not work, drop your arm all the way down so it hangs at your side, and then bring it
back up again.
• Under certain conditions, illumination may not turn on until about one second after
you turn the face of the watch towards you. This does not necessarily indicate
malfunction of the auto light switch.
• You may notice a very faint clicking sound coming from the watch when it is shaken
back and forth. This sound is caused by mechanical operation of the auto light
switch, and does not indicate a problem with the watch.
4