Casio 3721 Operation Manual

MA0410-EA
Modes and Hand Movement
Each press of the B B B B B button sounds a confirmation tone and cycles through available modes in the sequence shown below.
• The watch will revert to the Timekeeping Mode automatically if you leave it in any other mode without performing any operation for about two
or three minutes.
Timekeeping Mode
Hour Hand
If the time setting is not correct...
Normally, you should never need to adjust the time setting of the watch as long as it is
able to receive a time calibration signal. If signal reception is impossible for some reason,
use the procedures under "Adjusting the Home Positions" to check the home positions of
the hands, and make adjustments as required.
Power Supply
To ensure stable operation, be sure to allow the watch to be exposed to light as
much as possible.
The power supply of this watch uses a solar cell to generate electrical power, which is stored by a rechargeable battery. Using or storing
the watch where it is not regularly exposed to light, or allowing it to be blocked from light by your sleeve for long periods as you are
wearing it can cause the power of the rechargeable battery to run down.
• A low battery can cause timekeeping to stop, and can also cause time and alarm settings to be lost.
• Face illumination or alarm operation can cause hand movement to stop due to the sudden temporary drop in battery power. This does not
indicate malfunction, and normal operation will resume when the watch is exposed to light. Though hand movement stops, timekeeping
continues internally, and the hands will be adjusted to the correct setting when normal operation returns.
Checking the Battery Level
Low battery power is indicated when the the second hand starts to jump at two-second intervals.
Normal Low Power Alert
Battery level
drops due to
insufficient
charging.
1-second movement Jumps two seconds
If 2-second hand movement is being performed when the current time reaches midnight, the date indicator will change to the home
position indicator ( ). If battery power drops to the next lower level, and the hands will stop at 12 o'clock.
• Even after the battery drops to the level that timekeeping becomes disabled, you will be able to resume normal operation by charging the
battery.
• After timekeeping becomes disabled, the hands will move to the current time after the battery is recharged sufficiently.
• Keep the watch exposed to light until normal operation returns.
Operation Guide 3721
Minute Hand
Button
(Light)
Date
Button
(Mode Change)
Timekeeping Disabled
Battery level
Important!
drops further
Hands
due to
The following
stop at 12
insufficient
operations are disabled
o'clock.
charging.
during 2-second hand
movement.
• Auto and manual
calibration signal
reception
• Face illumination
• Alarm
Indicates date home position.
Receive Result Mode
Use this mode to check if
signal reception is being
performed normally.
The second hand will move
to either "GET" or "NG".
Receive Failed
Charging Precautions
Avoid charging the watch in the following locations, and anywhere
else where the watch may become very hot.
• On the dashboard of an automobile parked in the sun
• Very close to an incandescent light source or other sources of
heat
• In a location exposed to direct sunlight for long periods
Depending on the light source you are using, the
case of the watch may become quite hot during
charging. Take care to guard against burn injury
after charging.
To charge the battery
Point the solar cell (face) of the watch at a light source to charge
the battery.
• Remember that even a partial blockage of the solar cell reduces
charging efficiency.
Example: Positioning the watch
Solar Cell
• The illustration shows the resin band model.
Alarm Mode
OFF
ON
Use this mode to set the alarm time and to turn
Receive
the alarm on or off.
Successful
The second hand will move to either "ON" or "OFF".
Home Position Adjustment Mode
Use this mode to adjust
the home positions of
the analog hands.
The home positions of the
hands are correct when
they point to 12 o'clock.
Required Daily Charging Time
Charging Guide
• The following is the daily
Starting from a full charge, the watch
amount of charging required
should be able to continue operating
each day to support the
for about four months without further
operations under "Daily Use".
charging under the conditions
described below. Exposure Level
(Brightness)
Daily Use
Outdoor Sunlight
• Illumination: 1.5 second
(50,000 lux)
• Alarm: 10 seconds
Sunlight Through a
• Signal reception: 1
Window (10,000 lux)
Daylight Through
Making sure the watch is regularly
a Window on an
exposed to light ensures stable
Overcast Day
operation.
(5,000 lux)
Indoor Fluorescent
Lighting (500 lux)
• Charge Times Required to Advance to a Higher Level
Exposure Level Approximate Exposure Time
(Brightness)
Timekeeping Restored
Outdoor Sunlight
1 hour
(50,000 lux)
Sunlight Through a
2 hours
Window (10,000 lux)
Daylight Through a Window on
3 hours
an Overcast Day (5,000 lux)
Indoor Fluorescent
30 hours
Lighting (500 lux)
• Note that the above charging times are for reference only. Actual
charging time depends on a variety of environmental factors.
Approximate
Exposure
Time
6 minutes
30 minutes
48 minutes
8 hours
Full Charge
12 hours
61 hours
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