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Operation Guide 4739
5
• Leaving the watch in direct sunlight or some other very strong light source can
cause the battery level indicator to show a reading that is momentarily higher than
the actual battery level. The correct battery level indicator should appear after a few
minutes.
• The watch’s Home City code setting will change automatically to TYO (Tokyo)
whenever the battery drops to Level 5. With this Home City code setting, the watch is
configured to receive the time calibration signals of Japan. If you are using the watch
in North America or Europe, you will need to change the Home City code setting to
match your location whenever the battery drops to Level 5.
• If you use the illumination or alarms a number of times during a short period, the
hands of the watch will stop. Battery level indicator will show R at this time. Also, the
following operations will become disabled until battery power recovers.
Illumination
Beeper tone
Time calibration signal reception
After some time, battery power will recover and the above functions will be 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 12 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.
• For details about the battery operating time and daily operating conditions, see the
“Power Supply” section of the Specifications.
• Stable operation is promoted by frequent exposure to light.
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)
Approximate Exposure Time
5 minutes
24 minutes
48 minutes
8 hours
Recovery Times
The table below shows the amount exposure that is required to take the battery from
one level to the next.
– – –
9 hours
44 hours
89 hours
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)
Approximate Exposure Time
Level 5 Level 4 Level 3 Level 2 Level 1
2 hours
7 hours
13 hours
163 hours
32 hours
158 hours
321 hours
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• 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.
Power Saving Function
When turned on, the Power Saving function enters a sleep
state automatically whenever the watch is left in an area
where it is dark for a certain period. The table below
shows how watch functions are affected by the Power
Saving function.
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Power saving indicator
Elapsed Time
in Dark
60 to 70 minutes
6 or 7 days
Display
Blank, with Power Saving
indicator (PS) flashing
Blank, with Power Saving
indicator (PS) not flashing
Operation
All functions enabled, except
for the display
•Beeper tone, illumination, and
display disabled
•Analog timekeeping stopped
at 12 o’clock
•Auto receive disabled
• 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 turn Power Saving on and off
1.In the Timekeeping Mode, hold down A until the city
code starts to flash, which indicates the setting screen.
2.Press C nine times until the Power Saving on/off
screen appears.
3.Press D to toggle Power Saving on (PSON) and off
(PSOF).
4.Press A to exit the setting screen.
• The Power Saving indicator (PS) is on the display in all
modes while Power Saving is turned on.
Auto Return Features
• If you leave the watch in the Alarm or Hand Setting Mode, or with the battery level
indicator displayed for two or three minutes without performing any operation, it
automatically returns to the Timekeeping Mode.
• If you leave the watch with a flashing setting on the display for two or three minutes
without performing any operation, the watch automatically exits the setting screen.
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On/Off status
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 World Time Mode, the data you were viewing when you last exited
the mode appears first.
Radio-controlled Atomic Timekeeping Precautions
• Strong electrostatic charge can result in the wrong time being set.
• 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.
• The current time setting in accordance with the time calibration signal takes priority
over any time settings you make manually.
• The watch is designed to automatically update the date and day of the week for the
period January 1, 2000 to December 31, 2099. Setting of the date by the time
calibration signal cannot be performed starting from January 1, 2100.
• This watch can receive signals that differentiate between leap years and non-leap
years.
• Though this watch is designed to receive both time data (hour, minutes, seconds)
and date data (year, month, day), certain signal conditions can limit reception to time
data only.
• Normally, the signal reception date shown by the Last Signal screen is the date data
included in the received time calibration signal. When only time data is received,
however, the Last Signal screen shows the date as kept in the Timekeeping Mode at
the time of signal reception.
• If you are in an area where proper time calibration signal reception is impossible, the
watch keeps time with the precision noted in “Specifications”.
• If you have problems with proper time calibration signal reception or if the time
setting is wrong after signal reception, check your current city code, DST (summer
time), and auto receive settings.
Timekeeping
• 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 or when battery power drops to
Level 5.
• The current time for all city codes in the Timekeeping Mode and World Time Mode is
calculated in accordance with the Greenwich Mean Time (GMT) differential for each
city, based on your Home City time setting.
• The times for the Timekeeping Mode and all the city codes of the World Time Mode
are calculated in accordance with each city’s UTC differential.
• The UTC differential is a value that indicates the time difference between a
reference point in Greenwich, England and the time zone where a city is located.
• The letters “UTC” is the abbreviation for “Universal Time Coordinated”, which is the
world-wide scientific standard of timekeeping. It is based upon carefully maintained
atomic (cesium) clocks that keep time accurately to within microseconds. Leap
seconds are added or subtracted as necessary to keep UTC in sync with the Earth’s
rotation.
12-hour/24-hour Timekeeping Formats
The 12-hour/24-hour timekeeping format you select in the Timekeeping Mode is also
applied in all other modes.
• With the 12-hour format, the PM indicator (P) appears on the display for times in the
range of noon to 11:59 p.m. and no 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.
Illumination Precautions
• Illumination may be hard to see when viewed under direct sunlight.
• Illumination automatically turns off whenever an alarm sounds.
• Frequent use of illumination runs down the battery.
To recover from the sleep state
Perform any one of the following operations.
• Move the watch to a well-lit area.
• Press any button.