Citizen Corso BM8400-50A User manual

CONTENTS
A. BEFORE USING..........................................................................................2
B. SETTING THE TIME AND CALENDAR......................................................3
C. FUNCTIONS OF SOLAR POWERED WATCH ..........................................6
Insufficient Charge Warning Function..........................................................7
Quick Start Function ....................................................................................7
Overcharge Prevention Function .................................................................7
D. CARE AND HANDLING DURING CHARGING ..........................................8
E. ABOUT THE RECHARGEABLE CELL ......................................................9
F. TIME REQUIRED FOR CHARGING .........................................................10
G. IN THESE CASES .....................................................................................12
H. PRECAUTIONS.........................................................................................14
I. SPECIFICATIONS.....................................................................................20
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English

A. BEFORE USING
This watch is not powered by a conventional battery, but is powered by
converting light to electrical energy.
Once fully charged, the watch will continue to run for approximately 6 months
without additional charging. We do recommend exposing your watch to light
every day to ensure optimum performance. Always be sure to recharge the
watch before it stops.
Your watch features an Overcharge Prevention Function so there is no need to
worry about overcharging your watch.
A special energy storage cell is used to store electrical energy. This special cell
does not require replacement and is a clean energy unit that does not use any
toxic substances.
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Before using, be sure to fully charge your watch by exposing it to light.
(See “F. TIME REQUIRED FOR CHARGING”, for charge time reference)

B. SETTING THE TIME AND CALENDAR
Setting the time
1. Stop the second hand by pulling out the crown.
2. Turn the crown to set the time.
3. After setting the time, firmly push the crown back into its normal position.
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Time-setting position
Crown
Solar cell
Normal position
[1] Three-hand models without calendar display
* If your watch has a screw-type crown, lift up the crown to loosen it before
operation. Be sure to press the crown down firmly after operation.

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7
SUN
4
Time
setting
position
Time
setting
position
Calendar setting
position
Crown
Date
Solar cell
Normal position
[2] Models with calendar (date and weekday) display
* If your watch has a screw-type crown, lift up the crown to loosen it before
operation. Be sure to press the crown down firmly after operation.
[Date display models] [Date, day of the week
display models]
Solar cell
Crown
Date, day of the week
Normal position
Calendar setting
position
The position of the calendar may differ depending on models.

Setting the time
1. Stop the second hand by pulling the crown out to the 2nd click (time setting
position).
2. Turn the crown to set the time.
3. The watch will start after the crown is firmly pushed back into its normal
position.
Setting the calendar
1. Pull the crown out to the 1st click (calendar setting position).
2. Set the desired date by turning the crown counterclockwise.
3. Set the desired day of the week by turning the crown clockwise.
•In the case of date display models, turning the crown clockwise will result in
the loose play of the crown.
4. After you have set the calendar, be sure to press the crown back to its
normal position.
•Do not adjust the calendar when the watch is reading as below. Otherwise
the calendar may not change correctly.
* Date display models ..... between 9:00 pm and 1:00 am
* Date, day of the week display models ..... between 9:00 pm and 4:00 am
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C. FUNCTIONS OF SOLAR POWERED WATCH
If the charge becomes insufficient, a warning function will operate and the
display changes, as below.
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Normal time
display
Stop
Insufficient charge
warning display
One second
interval movement Two second
interval movement
If charged
sufficiently
If insufficiently
charged
When the watch is exposed to light, the Quick Start Function will begin operating
and the second hand will start moving. The correct time can be set once the watch
is fully charged.
If insufficient charge continues
If insufficiently charged and time is set

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The second hand changes to a two second
interval movement to indicate insufficient recharging.
Even in such a case, the watch keeps correct time, but
about 4 days after the two second interval movement
begins, the watch will stop.
After exposing the watch to light, recharging takes place
and the watch returns to one second interval movement.
Two second interval
movement
2 sec
2 sec
Quick Start Function
The watch will stop if it is completely discharged.
It will begin to operate soon after it is exposed to light.
(However, the time to start may vary according to the brightness of the light.)
Overcharge Prevention Function
You can recharge your watch without worry.
Once the special energy storage cell is fully charged, the overcharge prevention
function comes into operation and prevents over-charging of the energy storage cell.
Insufficient Charge Warning Function

D. CARE AND HANDLING DURING CHARGING
Notes on Use
To maintain optimal performance, be sure to expose your watch to light
regularly.
Please note that if you wear long sleeves, your watch may be hidden from light
and may result in insufficient charging. As such, additional exposure to light may
be necessary.
•When you take your watch off, be sure to place it in as bright an area as
possible.
Notes on recharging
•Avoid recharging your watch in areas of high temperatures (over about 60 °C /
140 °F
), otherwise the sensitive components of the watch may become damaged.
(e.g.) Incandescent lights generate heat sufficient to damage your watch. Be
sure to keep the watch at least 50cm (20inches) away from the bulb so
no damage occurs. We do not recommend the use of Halogen bulbs for
recharging.
Never place your watch on the dashboard or rear deck of a vehicle as the
heat generated in these areas can damage your watch.
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E. ABOUT THE RECHARGEABLE CELL
Unlike ordinary watches, the special rechargeable cell used in your watch
does not need regular replacement. This is a clean energy cell that will last
the life of the watch.
CAUTION:
The rechargeable cell should last the life of the watch. Never allow anyone other
than an Authorized Service Center to replace this cell. The movement is designed
to operate with only the original rechargeable cell. If an alternate cell is installed,
such as a conventional battery, the battery may become overcharged resulting
in damage to the movement and/or bursting of the cell, which could cause injury
to the user.
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F. TIME REQUIRED FOR CHARGING
Time required for recharging may vary according to the design of the watch
(color of the dial, etc) and operating environment. The following table will serve
as an approximate reference: (Table of recharging)
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Illuminance
(lux)
500
Environment
Inside an ordinary
office
Time required
From the stop state to the
one second movement
60 hours
One day
usage
4 hours
Empty to full
1000
60-70cm (24-28in.) under
a fluorescent light (30W)
25 hours 2 hours
3000
20cm (8in.) under a
fluorescent light (30W)
8 hours 40 minutes 150 hours
10000 Exterior, cloudy 3 hours 12 minutes 45 hours
100000 Exterior, summer,
sunny 18 minutes 2 minutes 12 hours

* The recharging time is the time the watch is continuously exposed to direct light.
Full recharging time...Time required to fully charge when the watch has
completely stopped.
One day usage ..........Time required to charge the watch sufficient for one-day
use with one-second interval operation.
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(Empty to full)
CAUTION:
When recharging the watch after it is completely in the stop state, be sure to pull
out the crown to the time setting position.
After recharging, set the time and push the crown firmly back into its normal
position.

G. IN THESE CASES
[If the watch warns that the energy is running short]
The second hand starts moving at two second intervals
in order to warn that the watch will stop functioning after
about 1 week. (Insufficient Charge Warning Function)
In such a case, expose your watch to light for a while to
cancel the warning. (The second hand returns to moving
at one second intervals when the energy is recharged.)
If the watch is left short of energy, it will stop functioning
after 4 days or so.
Two second
interval movement
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[If the watch warns you to set the time.]
When the watch that has stopped is exposed to light, the
second hand starts hitch movement. (Quick Start
Function)
The time elapsed before the second hand starts moving
depends on the illuminance of the light.
Even so, the second hand continues the hitch
movement to tell you that the watch indicates an
incorrect time because it had stopped.
In such a case, set the hands to the correct time.
* If the watch is insufficiently exposed to light, the
second hand will soon switch to moving at two second
intervals in order to warn that the energy is running
short.
Hitch movement

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H. PRECAUTIONS
CAUTION: Water-resistance performance
There are several types of water-resistant watches, as
shown in the following table.
Indication
Dial Case
(case back)
Specifications
OK
OK
OK
WATER RESIST or
No indication
WATER
RESIST(ANT)
Water-resistant to 3
atmospheres
WATER RESIST(ANT)
5 bar or
WATER RESIST(ANT)
Water-resistant to 5
atmospheres
WATER RESIST(ANT)
10/20 bar or
WATER RESIST(ANT)
Water-resistant to
10/20 atmospheres
WR50 or
WATER RESIST 50
WR100/200 or
WATER RESIST
100/200
Minor exposure to water
(washing face, rain, etc.)
The unit “bar” is roughly equal to 1 atmosphere.

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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.
Examples of use
Marine sports (skin
diving)
Scuba diving (with air
tank)
Operation of the crown
with moisture visible
NO NO NO
NO NO NO
OK NO NO
NO
OK
OK
Moderate exposure
to water (washing,
kitchen work,
swimming, etc.)
* WATER RESIST(ANT) xx bar may also be indicated as W.R. xx bar.

•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 water-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 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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•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 (crystal, 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.
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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 leave 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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•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.
Periodical inspections
Your watch needs inspection once in every two or three years for safety and
long use.
To keep your watch water-resistant, the packing needs to be replaced regularly.
Other parts need to be inspected and replaced if necessary.
Ask for Citizen geuine parts upon replacement.
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I. SPECIFICATIONS
1. Type: Analog solar powered watch
2. Accuracy: Within ±15sec/month (within a normal
temperature range of 5°C/41°F to
35°C/95°F)
3. Quartz oscillator frequency: 32,768Hz
4. IC: C/MOS-LSI (1 pc.)
5. Operational temperature range: –10°C/14°F to +60°C/140°F
6. Display features: Time: hour, minute, second
Calendar: date, day of the week (Models
with calendar display)
7. Additional features: Insufficient charge warning/Quick start/
Overcharge prevention
8. Duration time: Approx. 6 months (from full recharge to stop)
At least 4 days (from two second interval
movement to stop)
9. Power Source: Light converted to electrical energy stored in
a special rechargeable cell. (Not user
replaceable)
* Specifications are subject to change without prior notice.
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