Citizen B51 User manual

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English
CONTENTS
1. Features .................................................................................................. 4
2. Explanation of Displays and Buttons ................................................... 5
3. Setting the Time and Date .................................................................... 6
4. Characteristic Functions of Solar-Powered Watches ......................... 8
5. General Reference for Charging Times ............................................. 10
6. Charging Procedure ............................................................................ 11
A. Charging by Exposing the Solar Cell to Light ................................. 11
B. Charging by Swinging the Watch ..................................................... 13
7. Warning Features ................................................................................ 15
8. Using the Chronograph ....................................................................... 17
9. Zeroing the Chronograph Second Hand ........................................... 19
10. Helpful Hints in Using your Watch .................................................. 21
11. Secondary Battery ............................................................................. 22
12. Using the Tachymeter (When Provided) ......................................... 23
13. Precautions ......................................................................................... 24
14. Specifications ..................................................................................... 30
Make Sure the Watch is Sufficiently Charged Before Use
Check that the second hand of the watch is moving correctly in 1-second interval
movement before use. If the second hand is moving in 2-second interval move-
ment or is stopped, this indicates that the watch is not fully charged. When this
happens, expose the solar cell to light to recharge or recharge the watch by swing-
ing.
When exposing the watch to light, do not place the watch too close to the light
source. This can cause the watch to overheat which can lead to a possible mal-
function.

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2. Explanation of Displays and Buttons
Please refer to the illustration of the watch on the inside cover.
Name Time display
Hour display
Minute display
Second display
24 hour display
Setting the time and date
Chronograph display
Chronograph second (1/5
second) display
1: Hour hand
2: Minute hand
3: Second hand
4: 24 hour hand
5: Chronograph second hand
6: Chronograph minute hand
A: Button
B: Button
C: Crown
Chronograph minute display
Start/stop
Reset
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1. Features
This analog quartz watch incorporates a solar cell in the watch face. In addition to being
equipped with a photoelectric power generation function that converts light energy to
electrical energy, it also is equipped with a self-winding power generation function that
converts "movement of the watch" produced by swinging the watch while wearing on
the wrist into electrical energy. Once fully charged, the watch will continue to run for
approximately 5 months without recharging. In addition, this watch is also provided
with a chronograph function (60 minute clock) that allows measurement of time in 0.2
second (1/5 second) units.
This watch also uses a secondary battery for storing the electrical energy that is gener-
ated. This battery is completely free of mercury and other hazardous substances. Since
this secondary battery is able to be repeatedly charged and discharged, it is not required
to be periodically replaced as in the case of ordinary watch batteries.

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<Setting the Time>
(1)Pull the crown out to the time correction position (2nd position) so that the second
hand stops at the 0 second position.
(2)Turn the crown to set the time.
*The date changes at 12:00 AM. Set the time while being careful not to mistake AM
and PM.
(3)Push the crown in to the normal position in synchronization with a telephone time
service or other official time service.
<Setting the Date>
(1)Pull the crown out to the date correction position (1st position).
(2)Turn the crown to set the date.
Turning the crown towards you (counter-clockwise) advances the date by one day.
The date will not move if the crown is turned in the opposite direction (clockwise).
(3)Return the crown to the normal position.
*Do not attempt to set the date between the hours of 9:00 PM and 1:00 AM. Setting
the date during this time may not result in the date changing on the following day.
* If the crown is of the screw-tightened type, set the time and date after first loosening
the screw. Retighten the screw after the time and date have been set.
3. Setting the Time and Date
If the watch stops or the second hand moves at two second intervals when setting
the time, charge the watch by referring to Section 6 entitled, “Charging Procedure”
to return the watch to the normal 1-second interval movement before attempting to
set the time and date.
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60
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Hours
24 hour hand
Seconds
Minutes
Date correction (1st) position
Crown
Time correction (2nd) position
Normal position

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60
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[Time Setting Warning Feature]
When the time is set
while undercharged
Irregular 2-second
interval movement
When the watch is
charged either by
exposing to light or
swinging, the quick
start function is
activated causing the
hands of the watch to
start moving
Watch stops
4. Characteristic Functions of Solar-Powered Watches
When the watch becomes undercharged, the warning feature illustrated below is acti-
vated and the display of the watch (movement of the second hand) changes.
[Normal Time Display]
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30
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60
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30
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24
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8
4
When undercharged
When charged
1-second interval movement
When fully charged and the time is set
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[Insufficient Charge Warning Feature]
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60
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40
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60
45
30
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20
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8
4
45
30
2-second interval
movement
When undercharging is allowed to continue

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If the second hand of the watch is moving in 2-second interval movement or has stopped
due to undercharging, recharge the watch either by exposing the solar cell to light or by
swinging.
A. Charging by Exposing the Solar Cell to Light
* Expose the surface of the solar cell to a fluorescent lamp, incandescent light or sunlight
to recharge.
* If the watch is ordinarily concealed from the light as a result of wearing long sleeve
shirts and so on, the watch will be susceptible to becoming undercharged as a result of
not being exposed to light. Try to place the watch in as bright a location as possible
when it is not worn.
* When there are few opportunities for exposing the watch to light, the watch can also be
recharged by swinging in the manner described below.
[Precautions When Charging by Exposing to Light]
* Avoid charging the watch at high temperatures (approx. 60°C/140°F and above) since
allowing the watch to become overheated during charging can lead to a malfunction.
6. Charging Procedure
5. General Reference for Charging Times
(Case of Charging by Illuminating Solar Cell Only)
Charging times differ depending on the watch model (type of face, etc.). The charging
times shown in the table below are meant to only serve as a rough indicator of required
charging times.
*The charging
time indicated
refers to the
duration of
continuous
illumination.
Luminance
(Lux) Environment
Charging time
Charging
time for 1 day
of operation
Charging time from
stop until 1-second
interval movement
Full
charging
time
Typical office
Under a fluorescent
lamp (30 W) at a
distance of 60-70 cm
(24-28in.)
Under a fluorescent lamp
(30 W) at a distance of
20 cm(8 in.)
Cloudy day
Under direct sunlight
on a summer day
2 hours
45 minutes
15 minutes
4 minutes
2 minutes
37 hours, 30 minutes
15 hours
5 hours
1 hour, 30 minutes
30 minutes
335 hours
143 hours
45 hours
13 hours
2 hours, 30
minutes
Full charging time: Time from the state in which the watch is stopped until it is fully charged
Charging time for 1 day of operation: Time required for the watch to run for 1 day using the
normal time display (1-second interval movement)
500
1,000
3,000
10,000
100,000

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B. Charging by Swinging the Watch
When there are few opportunities for charging the watch by exposing to light, occasion-
ally charge the watch by swinging. In addition, for those persons who only wear the
watch for short periods of time (several days) or when there is little movement while
wearing the watch, it is also recommended to charge the watch by swinging.
Swing the watch back and forth over a dis-
tance of about 20-25 cm (8-10 in.) at the rate
of about 2-2.5 strokes per second.
* Swing the watch for about 300-500 times
(strokes) when it has stopped.
<How to Effectively Charge the Watch by Swinging>
Examples:
* Charging in close proximity to an incandescent lamp or halogen lamp which can
easily reach high temperatures.
* Charging in locations that can reach high temperatures such as on an automobile
dashboard.
* When charging with an incandescent lamp, always make sure to keep the watch at least
50 cm (20 in.) away from the lamp to prevent the watch from overheating.

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7. Warning Features
When this watch becomes undercharged, a warning feature is activated and the display
of the watch changes.
2-second interval
movement
<Insufficient Charging Warning Feature>
When the second hand is moving in 2 second intervals (moving once every 2 seconds),
this means that the watch is undercharged. Although the watch will continue to run
normally at this time, the watch will stop if 2-second interval movement is allowed to
continue for roughly 1 day. When this happens, charge the watch by referring to Sec-
tion 6 entitled, “Charging Procedure” so that it returns to normal 1-second interval
movement. Furthermore, the chronograph function cannot be
used when the insufficient charging warning feature has been
activated (during 2-second interval movement).
* If charging is only performed until the watch returns to 1-sec-
ond interval movement, it will again return to 2-second inter-
val movement within a few minutes. It is therefore recom-
mended to additionally charge the watch for at least one day’s
worth of charging by exposing to light or by swinging (200-
300 times) to ensure continuous operation.
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30
* Charging will not proceed efficiently if the watch is swung too fast or too slow.
* When swinging the watch, although the sound of the generator turning can be
heard from inside, this is normal and does not indicate a malfunction.
* The watch should be swung approximately 200-300 times to ensure 1 full day’s
worth of charging when running normally (1-second interval movement).
* Charging can be performed even more efficiently by combining charging by ex-
posing the watch to light and charging by swinging.
* Since this watch is provided with an overcharging prevention feature, there is no
risk of damage to the watch due to excess charging.

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8. Using the Chronograph
This chronograph is able to measure and display time in 0.2 second (1/5 second) units up
to a maximum of 59 minutes and 59 seconds. After completing measuring time for 60
minutes, it returns to the reset display and stops.
[Chronograph Reset Display]
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* If the chronograph second hand
does not return to the zero second
position when the chronograph has
been reset, correct the second hand
position by referring to Section 9
entitled, "Zeroing the Chronograph
Second Hand".
Chronograph seconds
Chronograph
minutes
<Time Setting Warning Feature>
After the watch has been recharged after having stopped due to being undercharged,
although the watch hands will begin to move, the time will not be correct. The second
hand will begin irregular 2-second interval movement (moving irregularly once every 2
seconds) at this time indicating that the time is incorrect. Reset the time after suffi-
ciently charging the watch by referring to Section 6 entitled, "Charging Procedure”.
When the time has been reset, the second hand will no longer move irregularly in two
second intervals, and return to either 1-second or 2-second interval movement. In the
case of 2-second interval movement, the watch must be additionally charged.
Irregular 2-second
interval movement
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9. Zeroing the Chronograph Second Hand
The zero position of the chronograph second hand may rarely shift out of position after
replacing the battery or after the watch has been subjected to a strong shock. When the
chronograph second hand does not return to the zero position when the chronograph has
been reset, correct the hand position using the following procedure.
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40
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Chronograph second hand Chronograph minute hand
Normal position
Crown
Correcting position
(2nd position)
A
B
<Measuring Time with the Chronograph>
(1) Pressing button starts and stops the chronograph.
(2) Pressing button when the chronograph is stopped returns the chronograph to the
reset display.
* If button is pressed by mistake during chronograph measurement, the chronograph
will return to the reset display. Be careful not to accidentally press button during
time measurement.
B
A
B
B
Reset Measurement Stop Reset
Can be repeated
A A
B
A

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10. Helpful Hints in Using your Watch
Exposing this watch to light (1,000 lux or more) for at least 3 hours per day or wearing
the watch for at least 12 hours per day will enable it to obtain the amount of charging
required to power the watch for approximately 1 day. The amount of charging varies
depending on the intensity of the light to which the watch is exposed, the manner in
which the watch is worn and individual differences, however.
<When the Watch is Worn Daily>
If the watch is exposed to light daily or worn daily for at least 12 hours, the watch will
be additionally charged each day. This will enable the watch to run continuously with-
out intentionally charging. When the watch is used where there are low levels of light or
when the amount of movement of the watch is low, such as during long periods of desk
work, the watch should occasionally be charged by swinging.
<When the Watch is Worn for Short Periods (Several Days)>
When the amount of time the watch is not worn is longer than the time it is worn, there
are few opportunities to expose the watch to light, or when the watch is not worn on the
wrist, the watch should occasionally be charged by swinging. If the watch is only worn
occasionally, it may stop before it is worn as a result of being undercharged. When this
happens, it is necessary to recharge the watch by exposing to light or swinging and then
reset the time prior to use.
<Correcting Procedure>
(1) Pull the crown out to the correcting position (2nd position).
(2) Press button to set the chronograph second hand to the 0 position. Each time
button is pressed causes the chronograph second hand to be corrected in the
clockwise direction by 0.2 seconds (1/5 second) at a time. (Pressing button con-
tinuously causes the second hand to advance rapidly.)
(3) Return the crown to the normal position.
(4) Press button to confirm that the chronograph second and minute hands are reset to
the 0 position.
* Although the chronograph minute hand will also move when correcting the chrono-
graph second hand, pressing button returns the chronograph minute hand to the zero
position.
* Always make sure to reset the time after completing the zeroing procedure.
A
B
A
A
B

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12. Using the Tachymeter (When Provided)
The tachymeter feature is used to measure traveling speed such as that of an automobile.
In the case of this watch, the average speed can be approximately determined for a certain
distance by measuring how many seconds it takes to travel 1 kilometer (measuring range:
maximum 60 seconds). To determine average speed, start the chronograph simultaneous
to the start of measurement. Stop the chronograph when the vehicle has traveled 1 kilo-
meter. An approximation of the average speed over that distance can be determined by
the position of the chronograph second hand at that time.
Example:
If it takes 45 seconds to travel
1 kilometer, then the average
speed over that distance is 80
kilometers/hour.
60
80
120
T
A
C
H
Y
M
E
T
E
R
Chronograph
second hand
Tachymeter
11. Secondary Battery
CAUTION: Handling of Secondary Battery
* Do not attempt to remove the secondary battery from the watch. If the secondary
battery should happen to be removed, store it in a location out of the reach of small
children to prevent it from being swallowed accidentally.
* If the secondary battery has been swallowed, consult a physician immediately and seek
medical assistance.
CAUTION: Only Use the Specified Battery
* Never attempt to use a battery other than the specified secondary battery in this watch.
Although the watch is constructed to prevent the watch from operating if another type
of battery is installed, if a silver battery or other type of battery is forcibly installed and
the watch is recharged with that battery in use, the battery may become overcharged
causing it to rupture and resulting in the risk of damage to the watch and injury to the
wearer. When replacing, always make sure to only use the specified secondary bat-
tery.

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OK
NO NO NO
NO
NO
NO
NO
NO NO
OK OK
Examples of use
For correct use within the design limits of the watch, confirm the level of water-
resistance of your watch, as indicated on the dial and case, and consult the table.
Moderate exposure to
water (washing, kitchen
work, swimming, etc.)
Marine sports
(skin diving)
Operation of the
crown or button with
moisture visible
Scuba diving
(with air tank)
The unit "bar" is roughly equal to 1 atmosphere.
13. Precautions
No indication OK
Water-resistant to
10/ 20 atmospheres
Water-resistant to 5
atmospheres
Water-resistant to 3
atmospheres
Specifications
WATER
RESIST (ANT)
WATER
RESIST (ANT)
5 bar
WATER
RESIST (ANT)
10/20 bar
OK
WATER RESIST
10/20 bar
or no indication
WATER RESIST
5 bar or no indication
CAUTION: Water-resistance performance
There are several types of water-resistant watches,
as shown in the following table.
Minor exposure to water
(washing face, rain, etc.)
Indication
Dial Case
(Case back)
OK

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• If seawater enters the watch, place the watch in a box or plastic bag and immediately
take it in for repair. Otherwise, pressure inside the watch will increase, and parts (crys-
tal, crown, buttons, etc.) may come off.
CAUTION: Keep your watch clean.
• Leaving dust and dirt deposited between the case and crown may result in difficulty in
pulling the crown out. Rotate the crown while in its normal position, from time to time,
to loosen dust and dirt and then brush it off.
• Dust and dirt tend to be deposited in gaps in the back of the case or band.
Deposited dust and dirt may cause corrosion and soil your clothing. Clean the watch
occasionally.
Cleaning the Watch
• Use a soft cloth to wipe off dirt, perspiration and water from the case and crystal .
• Use a soft, dry cloth to wipe off perspiration and dirt from the leather band.
• To clean a metal, plastic, or rubber watchband, wash away dirt with mild soap and
water. Use a soft brush to remove dust and dirt jammed in the gaps in the metal band. If
your watch is not water-resistant, take it to your dealer.
NOTE: Avoid using solvents (thinner, benzine, etc.), as they may mar the finish.
• Water-resistance for daily use (to 3 atmospheres): This type of watch is water-resistant
to minor exposure to water. For example, you may wear the watch while washing your
face; however, it is not designed for use underwater.
• Upgraded water-resistance for daily use (to 5 atmospheres): This type of watch is wa-
ter-resistant to moderate exposure to water. You may wear the watch while swimming;
however, it is not designed for use while skin diving.
• Upgraded water-resistance for daily use (to 10/20 atmospheres): This type of watch
may be used for skin diving; however, it is not designed for scuba or saturated diving
using helium gas.
CAUTION
• Be sure to use the watch with the crown pressed in (normal position). If your watch has
a screw-type crown, be sure to tighten the crown completely.
• Do NOT operate the crown or button with wet fingers or when the watch is wet. Water
may enter the watch and compromise water-resistance.
• If the watch is used in seawater, rinse with fresh water afterward and wipe with a dry
cloth.
• If moisture has entered the watch, or if the inside of the crystal is fogged up and does
not become clear within a day, immediately take the watch to your dealer or Citizen
Service Center for repair. Leaving the watch in such a state will allow corrosion to form
inside.

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• Do NOT subject the watch to a strong shock such as dropping it onto a hard floor.
• Avoid using the watch in an environment where it may be exposed to chemicals or
corrosive gases.
If solvents, such as thinner and benzine, or substances containing such solvents come
in contact with the watch, discoloration, melting, cracking, etc. may result. If the watch
comes in contact with mercury used in thermometers, the case, band or other parts may
become discolored.
CAUTION: Operating environment
• Use the watch within the operating-temperature range specified in the instruction manual.
Using the watch where temperatures are outside the specified range, may result in
deterioration of functions or even stoppage of the watch.
• Do NOT use the watch in places where it is exposed to high temperature, such as in a
sauna.
Doing so may result in a skin burn.
• Do NOT Ieave the watch in a place where it is exposed to high temperature, such as the
glove compartment or dash-board of a car.
Doing so may result in deterioration of the watch, such as deformation of plastic parts.
• Do NOT place the watch close to a magnet.
Timekeeping will become inaccurate if you place the watch close to magnetic health
equipment such as a magnetic necklace or a magnetic latch of a refrigerator door or
handbag clasp or the earphone of a mobile phone. If this has occurred, move the watch
away from the magnet and reset the time.
• Do NOT place the watch close to household appliances that generate static electricity.
Timekeeping may become inaccurate if the watch is exposed to strong static electricity,
such as is emitted from a TV screen.

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14. Specifications
1. Caliber No.: B51
2. Type: Analog solar-powered watch
3. Accuracy: Within ±15 seconds per month on average (when worn at normal tempera-
tures: +5°C to +35°C/41°F to 95°F )
4. Operating Temperature Range: -10°C to +60°C/14°F to 140°F
5. Display Functions: Time (hours, minutes, seconds, 24 hours)/date
6. Additional Functions:
* Chronograph function: 0.2 second (1/5 second) units, 60 minutes
* Self-winding power generation function
* Insufficient charging warning feature
* Time setting warning feature
7. Continuous Operation:
* From fully charged to stopping - Approx. 5 months
* From 2-second interval movement to stopping -Approx. 1 day
8. Battery: Secondary battery - 1
*Specifications are subject to change without notice.
*