Casio 5251 User Manual

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MA1112-EA

Operation Guide 5251 (OC)

About this manual

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Operations are performed using the watch’s crown and the A button.

Hand Functions

z Hour Hand
x Second Hand
c Minute Hand
v Day Indicator

This User’s Guide uses numbers shown above to identify watch hands and
indicators.

Important!

x A button is designed to protect against accidental pressing. Use a thin

The
pointed object to press the depression of the button to operate it.
In the illustrations in this manual, the

x A button is emphasized for ease of

understanding.

Congratulations upon your selection of this CASIO watch.

Note that the product illustrations in this manual are intended for reference only, and so the actual product

x

may appear somewhat different than depicted by an illustration.

Note that CASIO COMPUTER CO., LTD. assumes no responsibility for any damage or loss suffered by
you or any third party arising through the use of this product or its malfunction.

About the face

ENGLISH

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The following explains the meanings of the markings on the watch’s face.

Y (YES)/N (NO): Time calibration signal reception result1.

Y (YES): Successful
N (NO): Unsuccessful

See “To check the result of the latest receive operation” (page E-21).

x

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RC: Receive in progress2.

See “To perform manual receive” (page E-20). x

A (AM)/P (PM): AM and PM indications when setting the time3.

See “To set the time manually” (page E-24).

x

CN (HKG, HONG KONG)/OFF/JP (TYO, TOKYO): 4.
Signal reception location

See “Radio Controlled Atomic Timekeeping” (page E-16). x

E-1

E-2

Crown Operations

The crown can be pulled out to one of two (click) positions. Never apply undue force when pulling out the
crown.

Important!

x

When pulling out the crown, avoid using undue force, which creates the risk of personal injury to your
fi ngers and fi ngernails, and of watch malfunction.

First click

For selecting the location setting

Second click

For confi guring time, date and other settings

Note

When you push the crown back in from the fi rst click, the x
indicates whether the watch’s battery requires charging before resuming regular timekeeping. See
“Charging Guide” (page E-12).

E-4

Second Hand will perform movement that

Things to check before using the watch

1. Observe the movement of the x Second Hand.

Is the x Second Hand moving smoothly at one-second intervals?

NO YES

x Second Hand moving in the following pattern.

1 second

Is the x Second Hand moving at
two-second intervals or is it stopped
completely?

Battery is low.

1 second 2 seconds

NO

YES

Battery is starting to go low.

The watch is charged. For details about charging,
see “Charging the Watch” (page E-10).

NEXT

Go to step 2.

YES

High-speed Forward and Reverse Movement

While the crown is pulled out, rotating it more than one full turn either way will
cause the hands or Day indicator to start to move at high speed. High-speed
movement will continue even if you release the crown.

High-speed Cancel

Rotate the crown in the reverse direction of the movement or press the A
button.

Note

Leaving the crown pulled out for more than two minutes without performing any operation will x
automatically cause the setting operation to become disabled. If this happens, press the crown back in
and then pull it out again to confi gure settings.
High-speed movement can be used when setting the current time (page E-24) and when performing

x

home position adjustment (page E-29).

2. Check the current location settings.

Use the procedure under “Confi guring Time and Date Settings” (page E-22) to confi gure your location
settings.

Important!

x

Proper time calibration signal reception and time settings depend on correct location setting. Make
sure you confi gure these settings correctly.

3. Set the current time.

x To set the time using a time calibration signal

See “To get ready for a receive operation” (page E-18).

x To set the time manually

See “Confi guring Time and Date Settings Manually” (page E-24).

The watch is now ready for use.

For details about the watch’s radio controlled timekeeping feature, see “Radio Controlled Atomic x
Timekeeping” (page E-16).

E-3

E-5

Charge the watch by placing it in a location where it is exposed to light. For details, see “Charging the
Watch” (page E-10).

E-6

E-7

Operation Guide 5251 (OC)

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Contents

E-2 About this manual

E-3 About the face

E-4 Crown Operations

E-6 Things to check before using the watch

E-10 Charging the Watch

E-13 To use the charging guide
E-15 To recover from the sleep state

E-16 Radio Controlled Atomic Timekeeping

E-18 To get ready for a receive operation
E-20 To perform manual receive
E-21 To check the result of the latest receive operation

E-22 Confi guring Time and Date Settings

E-23 To check the current location setting
E-23 To change the location setting
E-24 To set the time manually
E-26 To set the date manually

E-8

Charging the Watch

The face of the watch is a solar panel that generates power from light. The generated power charges a
built-in rechargeable battery, which powers watch operations. The watch charges whenever it is exposed
to light.

Charging Guide

Warning!
Leaving the watch in bright light for charging 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.

x

On the dashboard of a car parked in direct sunlight
Too close to an incandescent lamp x
Under direct sunlight x

Whenever you are not wearing
the watch, be sure to leave it in
a location where it is exposed
to light.

Best charging performance

x

is achieved by exposing
the watch to light that is as
strong as possible.

When wearing the watch,
makes sure that its face is
not blocked from light by the
sleeve of your clothing.

The watch may enter a sleep

x

state (page E-14) if its face is
blocked by your sleeve even
only partially.

E-29 Adjusting the Home Positions

E-32 Troubleshooting

E-36 Specifi cations

Important!

x

Keep the watch in an area normally exposed to bright light when storing it for long periods. This helps
to ensure that power does not run down.
Storing the watch for long periods in an area where there is no light or wearing it in such a way that it is x
blocked from exposure to light can cause power to run down. Make sure that the watch is exposed to
bright light whenever possible.

Power Levels

You can get an idea of the watch’s power level by observing the movement of
the

Second Hand in the regular timekeeping.

Level Hand Movement Charge

1 Normal. Battery is charged.

x

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Movement indicates the
current charge level.

Second Hand moves in the following

pattern.

2

1 second

intervals.

3

position).

4

stopped at 12 o’clock.

1 second 2 seconds

Second Hand moves at two-second

Day Indicator changes to 1 (home

Second Hand stopped.
Hour Hand and c Minute Hand

Battery is starting to go low.

Battery is low.

Battery is very low.

E-9

E-10

When power drops to Level 4, all functions will be disabled but the watch will continue to keep time x
internally for about one week. If you recharge the battery suffi ciently during this period, the analog
hands will move automatically to the correct setting and regular timekeeping will resume. After one
week, all settings (including timekeeping) will be cleared. Recharging the battery will reset all settings
to their initial factory defaults.

Charging Guide

The charging guide causes the x Second Hand to perform movement that gives you a rough idea of
whether the watch needs to be exposed to light in order to charge the battery.

E-12

Charging Times

Level Change *2

Level 4 Level 3 Level 2 Level 1

Exposure Level (Brightness)

Outdoor sunlight (50,000 lux) 8 minutes 2 hours 25 hours

Window sunlight (10,000 lux) 30 minutes 4 hours 93 hours

Window sunlight on cloudy day (5,000 lux) 48 minutes 6 hours 151 hours

Indoor fl uorescent lighting (500 lux) 8 hours 59 hours – – –

1 Approximate exposure each day to generate power for normal daily operation. *
2 Approximate exposure to take power up one level. *

The above times are for reference only. Actual times depend on lighting conditions.

x

For details about the operating time and daily operating conditions, see the “Power Supply” section of x
the Specifi cations (page E-36).

Power Saving

A Power Saving feature causes the watch to enter a sleep state automatically whenever it is left for a
certain period in an area where it is dark.

Daily Operation

*1

To use the charging guide

Pull the crown out to the fi rst click. The 1.
setting. Next, push the crown back in.

For about one second, the

x

battery requires charging.

Charge is very low.
Leave the watch in bright
light for long time until
charged.

The current charging requirement is indicated whenever you push the crown back in from the fi rst x
click.
Failure to expose the watch to light when charging is required will cause the charge to be reduced x
even further.
The charging guide is based on a calculated value (not the actual battery charge). Because of this,

x

the battery charge may go low even if the charging guide indicates that immediate charging is not
required. If this happens, expose the watch to light as soon as possible to charge the battery.

How Power Saving works

The watch will enter the sleep state if it is left in a dark location for about one week.

x

In the sleep state:

All hands stop at 12 o’clock. −
Auto Receive is disabled. −

Internal timekeeping continues to operate normally. −
The watch will not enter a sleep state between 6:00 AM and 9:59 PM. If the watch is already in a sleep x
state when 6:00 AM arrives, however, it will remain in the sleep state.

To recover from the sleep state

Move the watch to a well-lit area, press the A button, or pull out the crown to the fi rst click.

x

It can take up to eight minutes for the watch to resume normal operation after recovering from the sleep
state. Do not perform any button operations during that time.

Second Hand will move to the currently selected location

Second Hand will perform movement that indicates whether the watch’s

Battery is charged.

Charge is low.
Consider leaving the watch in
light for charging.

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Charge is low.
Leave the watch in light for charging.

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E-14

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