Casio 3707 Owner's Manual

MA0410-EA

Operation Guide 3707

Power Supply

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. To ensure stable operation, be sure to allow the watch to be exposed to light as much as possible when you are wearing or storing it.

Power Saving

Power Saving puts the watch into a sleep state, which will cause the second hand to stop moving whenever the watch is left in the dark.

• Note that hand movement may stop if the watch is blocked from light by your sleeve.

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.

Checking the Battery Level

Normal	Low Power Alert	Timekeeping Disabled
Battery level		Battery level
drops due to		drops further due
insufficient		to insufficient
charging.		charging.

How the sleep state works

The second hand stops whenever the watch is left in the dark for about 60 or 70 minutes between the hours of 10:00 p.m. and 6:00 a.m. Time calibration reception continues to be performed at this time. If the watch is left in the dark for an additional seven or eight days, the hour and minute hand also stop. Time calibration is not performed while the hour and minute hands are not moving.

• Timekeeping continues inteLnti

Jumps two seconds.		Date indicator becomes		Hands stop at
		“ ” at midnight.		12 o’clock.
Normal	Normal operation
Low Power Alert	Time calibration signal reception disabled
Timekeeping Disabled	Timekeeping disabled

•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.

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.

Charging Guide

Starting from a full charge, the watch should be able to continue operating for about five months without further charging under the conditions described below.

Daily Use (All time values are approximate.)

• Signal reception: 6 minutes

Making sure the watch is regularly exposed to light ensures stable operation.

Required Daily Charging Time

•The following is the daily amount of charging required each day to support the operations under “Daily Use”.

	Exposure Level	Approximate
		Exposure
	(Brightness)
		Time
	Outdoor Sunlight	6 minutes
	(50,000 lux)
	Sunlight Through
	a Window	30 minutes
	(10,000 lux)
	Daylight Through
	a Window on an	48 minutes
	Overcast Day
	(5,000 lux)
	Indoor
	Fluorescent	8 hours
	Lighting
	(500 lux)

• Charge Times Required to Advance to a Higher Level

	Exposure Level (Brightness)	Approximate Exposure Time
		Timekeeping Restored	Full Charge
	Outdoor Sunlight (50,000 lux)	1 hour	16 hours
	Sunlight Through a Window (10,000 lux)	3 hours	78 hours
	Daylight Through a Window on an Overcast Day	4 hours	– – –
	(5,000 lux)
	Indoor Fluorescent Lighting (500 lux)	37 hours	– – –

•Note that the above charging times are for reference only. Actual charging time depends on a variety of environmental factors.

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Operation Guide 3707

How a Radio-controlled Watch Works

What is a radio-controlled watch?

Your radio-controlled watch is designed to receive a time calibration signal that contains standard time data, and adjust its current time setting accordingly.

		Long-wave		Signal is received
	Transmitter	time		using built-in antenna.
		calibration
		signal
				Watch decodes
				received data
			Signal data	and converts it
				to time data.
			Decode
	Cesium		Time data	Time is adjusted
	atomic clock	Watch	Internally	according to
				time data.

After the watch receives the Standard Time signal, it performs internal calculations to determine the current time. Because of this, there may be an error of up to one second in the displayed time.

Calibration Signal

•The Japanese calibration signal (Call Sign: JJY) is maintained by the National Institute of Information and Communications Technology (NICT). It is a long wave signal transmitted 24 hours a day from the Mt. Otakadoya transmitter (40kHz) located in Tamura-gun, Fukushima Prefecture, and from the Mt.

Hagane transmitter (60kHz) located on the border between Saga Prefecture and Fukuoka Prefecture.

Note that transmission of the time calibration signal may be interrupted occasionally due to maintenance, lightning, etc.

Reception Range

This watch is designed to receive either the Mt. Otakadoya signal (40kHz) or the Mt. Hagane signal (60kHz), whichever is strongest.

•Under optimum conditions, the calibration signal should be receivable up to 1,000 kilometers from the transmitter. Note that the wave is relatively weak at distances greater than 500km, so reception may be poor at long distances.

•Geographic contours, nearby buildings, seasonal conditions, the time of day, can even make reception impossible even when you are within range of the transmitter.

•Reception is best at night.

Transmitter Locations	1000km
500km	500km	Mt. Otakadoya
		(40kHz)
Mt. Hagane
(60kHz)
	1000km

Receiving the Calibration Signal

There are two methods you can use to receive the time calibration signal.

Auto receive (Reception is performed automatically at midnight, 1:00, 2:00, 3:00 and 4:00 each morning.)

•Auto receive is terminated as soon a reception is successful.

•If auto receive is not successful for any of the normal auto receive operations shown above, auto receive is performed one more time at 5:00 a.m.

•Successful auto receive keeps timekeeping accurate.

Manual receive (You initiate reception using a button operation.)

To position the watch for optimum reception

Remove the watch from your wrist and place it somewhere so its right side (9 o’clock side, where the antenna is located) is facing a window.

• Do not move the watch while it is receiving the calibration signal.

Time Required for Reception

A calibration signal receive operation takes anywhere from about two to seven minutes.

To perform manual receive

In any mode, hold down the B button for about two seconds.

•The second hand will move to READY, and signal reception will start.

9 o’clock side

Or

READY

To interrupt reception

Press any button. This will cause the watch to return to the Timekeeping Mode.

When reception is successful

The watch will terminate reception and adjust the current time. Next the second hand will move to

GET.

When reception is not succesful

The second hand will move to NG (No Good), without adjusting the time setting.

•After the second hand is pointing at GET or NG, the watch will return to the Timekeeping Mode if you press any button or if you do not perform any operation for about one or two minutes.

Location

Reception is difficult and may even be impossible in the locations described below. Avoid such locations when performing signal reception.

• You should think of your watch operating like a radio or TV when it is receiving the calibration signal.

Among or near buildings

Next to a household appliance or office equipment (TV, speaker, fax, computer, cell phone, etc.)

Near high-voltage lines

In a location where there is radio interference (construction site, airport, etc.)

Inside a vehicle (automobile, train, plane, etc.)

Near mountains

If you are experiencing problems with reception, move away from the types of locations described above to a location with better reception, and try again.

Hand Operation During Signal Reception

Second Hand .....................	The second hand moves to READY when the reception operation starts,
	indicating that the watch is getting ready to receive. It points to WORK
	while actual reception is in progress.
Hour and Minute Hands ... The hour and minute hands continue to operate normally.
Note that the second hand does not move during signal reception.

To check the result of the last signal receive operation

In the Timekeeping Mode, press the B button. This enters the Receive Result Mode.

• If the watch was able to perform a successful signal receive
operation since midnight, the second hand will move to GET. If
the watch has been unable to receive any signal successfully,
the second hand will move to NG.
• To return to the Timekeeping Mode, press the Bbutton twice.	GET
• The watch will also return to the Timekeeping Mode if you do not
perform any operation for about one or two minutes.

Calibration Signal Reception Precautions

•Auto reception can be performed while the watch is in the Timekeeping Mode only.

•If the hands become misaligned for some reason, they may not indicate the correct time, even if the time calibration signal is received normally. If this happens, use the procedure under “Adjusting Home Positions” to adjust the home positions of the hands and the date.

•Pressing any button while auto reception is in progress will cause reception to stop.

•This watch is designed to adjust its current time setting in accordance with the calibration signal transmitted in Japan only. It operates like a standard (non-radio controlled) watch outside of the range of the receivable time calibration signal transmitters.

•When the watch is unable to receive the time calibration signal for some reason, timekeeping accuracy is within ±20 seconds per month.

•Proper reception may be impossible if there is something blocking the signal.

•The watch’s calendar shows dates up to the year 2099. Attempting a receive operation after that causes an error.

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