Citizen Eco-Drive b740 User manual

INSTRUCTION MANUAL

a1
2
4
8
7
g
f
b
e
3
d
6
c
5
(A)
(B)

1
This watch is an analog diver's watch into which an electronic depth meter function
and chronograph function are built.
• When the water sensor gets wet, the watch is automatically shifted to the dive
mode. (Depth meter function)
• The maximum depth in diving is automatically memorized. (Maximum depth
memorizing function)
• The chronograph function measures the time in units of one second for 50 minutes
at maximum. (Chronograph function)
• This watch is a solar-powered watch provided with a solar power generation (Eco-
Drive) function.
Before using
When the watch does not operate according to the instruction manual, it is
insufficiently charged.
Charge the watch for more than 4 hours, approximately 20 cm (8 in.) away
from the fluorescent or incandescent lamp (30 W) as light sources.
When charging the watch, do not put it too close to the light source.
* When charging the watch under direct rays of the sun, charge for more
than an hour.
IMPORTANT

2
Safety Precautions (Instructions to be followed at all times)
This manual contains the following instructions that should be strictly followed at all
times to prevent injury to yourself and other persons as well as damage to property.
■Injuries and damage that might be caused by using the watch improperly or
neglecting any of the instructions or precautions contained in this manual are
classified with the following symbols.
DANGER
WARNING
CAUTION
■Important instructions that should be followed are classified with the
following symbols.
Warning (caution) symbol followed by instructions that should be
followed or precautions that should be observed
Warning (caution) symbol followed by prohibited matters.
This symbol indicates matters for which there is the
risk of minor injury or property damage.
This symbol indicates matters for which there is the
risk of death or serious injury.
This symbol indicates matters for which there is a high
risk of death or serious injury.

3
DANGER
Please read this manual carefully to make sure you have a thorough understanding of
the handling and operating procedures, displays and limitations of this watch and
ensure its proper use. Improper use of this watch or failure to observe displayed
warnings, cautions and instructions can result in the risk of a fatal or serious accident.
CAUTION
Diving is a sport that involves risk. When using this watch for diving, make sure you
have a proper understanding of the procedures for handling the watch as described in
this manual and observe proper procedures. Handling of this watch in a manner
contrary to that described in this manual may prevent the watch from functioning
properly.
Request to Customers
All repairs performed on this watch, excluding repairs involving the band, are to be
performed at the CITIZEN. When desiring to have your watch repaired or
inspected, please contact the Citizen Service Center.

4
WARNING – Before using this watch for diving –
Since the depth meter function of this watch is not approved as an official depth
gauge, be sure to use this function as an auxiliary means to know the
approximate depth.
Diving is a sport that involves risk. Before using this watch while diving, be sure
to receive diving instruction and training from a qualified instructor to acquire
the experience and skills that are required for safe diving. Always observe the
applicable rules.
• Diving with this watch must be limited to recreational diving (diving without
decompression). Do not use this watch for decompression diving, saturated diving
or diving in a high altitude. The depth meter function of this watch works normally in
seawater with temperatures of +10°C to +40°C (50°F to 104°F), however, depth
indication is incorrect in water other than seawater (specific gravity: 1.025).
• Rapid and sharp change of the atmosphere and/or seawater temperature
occasionally affects the indication and performance of the watch. Therefore, it is
recommended that this watch be used together with another depth gauge. Read the
indication of this watch as a rough guideline.
• Even recreational diving involves many risks. Before using this watch as an
auxiliary instrument for diving, be sure you receive right training in scuba diving by a
qualified instructor in order to acquire experience and technique necessary for safe
diving as well as to master the proper way to handle and operate this watch.

WARNING
Each diver should take responsibility for planning and executing his or her own diving
plan to ensure safe diving.
This watch is not equipped with a function that prevents decompression sickness. In
addition, this watch is also unable to check differences in physiological functions of
individual divers or differences in physical condition on that day.
Since the occurrence of decompression sickness is greatly affected by physical
condition, the degree of the risk of decompression sickness varies depending on your
physical condition on that day. It is recommended to avoid diving whenever you are in
poor physical condition such as when you are ill, fatigued, have not had enough sleep
or have a hangover.
CAUTION – Before using this watch for diving –
When using this watch, the user must receive general training and instructions, and
follow various rules.
The user should not use this watch without a good knowledge and understanding of
the proper way to handle and operate it and the precautions on it. If this watch is
improperly used, it may result in malfunction or breakdown of the watch.
5

CAUTION – For safe diving –
• When diving, obey the rules of the buddy system every time. (Buddy system means
that two divers pair with each other for safe diving.)
• For safety, it is advised that you enjoy sports diving in the depths around 20 m (60
ft).
• Before diving with this watch, fully charge the watch without fail. When the watch is
not sufficiently charged (the function hand points at “NG”), the depth meter function
cannot be used.
If charge of the watch becomes low considerably during diving, the depth meter
function to measure depth is discontinued.
• After diving, take a good rest following safety rules. If you take a plane or move to a
high place without a sufficient rest after diving, you may suffer from decompression
sickness (caisson disease).
6

PROHIBITION
Do not use this watch for diving under the following circumstances.
• When the function hand indicates “NG” on the charging level index.
… When the function hand indicates “NG” on the charging level, the watch will not
measure the depth. If the function hand points at “NG” on the charging level during
diving, immediately stop using the depth meter function of the watch since the
watch discontinues depth measurement in this condition.
• When the watch stops running or malfunctions. (Be careful not to knock the watch
against hard things such as diving apparatus, rocks, etc.)
• When the water temperature is out of the guaranteed range for measuring depth.
… The accuracy of the depth meter function is guaranteed under the condition that
water temperature is between +10°C and +40°C (50°F and 104°F).
• For the purpose of knowing a risk of a behaviour or situation.
…This watch is not designed to serve as a drowning prevention instrument or an
emergency instrument.
• In the environment filled with helium gas (saturated diving, etc.).
…Use of the watch in such conditions may cause failure or breakdown of the
watch.
–Circumstances that prohibit use of this watch
in diving –
7

Precautions in diving
WARNING – Before diving –
• Check to see if the watch is set to the time mode. (When the watch is set to the
chronograph mode, it will not shift to the dive mode.)
• Check the indication of the function hand (on the charging level index). When the
function hand points to “NG”, the watch will not shift to the dive mode because of
insufficient charge. If the function hand points to “NG”, charge the watch sufficiently
so that the hand indicates “LV.2 (level 2)” or “LV.1 (level 1)”.
• Check to see if the function hand (serving as the depth indicator) points to “0 m (0
ft)” position when the water sensor is activated and the watch enters the dive mode.
• Check to see if the crown is completely pressed in and screwed down tightly.
• Check to see if the watchband and the watch are tightly fastened to each other.
• Check to see that there are no cracked, damaged or broken parts on the
watchband and glass.
• Check to see if the rotating bezel rotates normally.
• Check to see if the time and date are set correctly.
8

9
WARNING – During diving –
• Avoid quick ascending, otherwise you may suffer from submarine sickness or a
functional disorder in some way. Whenever you ascend in water, carefully keep a
safe speed.
• Do not disturb any push buttons or the crown except button (B) (for displaying the
memorized maximum depth) throughout the dive, otherwise the watch may fail in
water-resistance.
• If the watch does not operate correctly in the water, start ascending to the surface
immediately. Start your ascent immediately, but be sure to stay below an ascent
rate of 9 m (30 ft)/min.
WARNING – After diving –
• After confirming that the crown is screwed down tightly, wash out seawater, mud,
sand, etc. sticking to the watch, with fresh water. Then, wipe off water and
moisture with a dry soft cloth.
• Remove any debris or dirt that has become trapped in the sensor. If the sensor
part is packed with dust, etc., wash it out with fresh water. Neither remove the
sensor cover nor pick at it with a sharp-point in order to remove particles of dust,
etc. collected in the sensor. In addition, do not blow highly compressed air onto the
pressure sensor with an air gun. In case it is difficult to wash out dust, consult the
Citizen Service Center.

10
CAUTION – Regarding diving at high altitudes or in fresh water –
• If you intend to use this watch for diving in a high place or in fresh water, be sure to
have a special education in safe diving beforehand.
• Do not use the depth meter function of this watch in a high place 4,000 m (13,120
ft) or more above sea level, because the watch gives incorrect measurement of
depth in such a place.
• This watch indicates a depth based on the specific gravity (1.025) of seawater.
Therefore, if the watch is used in fresh water, the real depth is 2.5% deeper than the
indication of the watch.
Example: 20 m (65 ft) (indicated depth) x 1.025 = 20.5 m (67 ft) (real depth)
When the watch is shifted to the dive mode, the pressure sensor regards the
ambient pressure as that on the sea level (0 m/0 ft in depth or altitude). If the
watch is shifted to the dive mode in a high place, it regards the pressure on the
surface of the water as that on the sea level (namely 0 m/0 ft in depth/altitude). In
short, the watch always regards the surface of the water as the sea level (0 m/0 ft)
except in a place 4,000 m (13,120 ft) or more above sea level. Therefore, you are
advised not to use the depth meter function of this watch in a high place 4,000 m
(13,120 ft) or more above sea level for the reason that the watch gives incorrect
measurement of depth in such a place as mentioned previously.

BEFORE USING
Before using, make sure the watch is sufficiently charged by
exposing it to the light.
A rechargeable cell is used in this watch to store electrical energy. If the watch is fully
charged once, it will continue running for about two months.
When the watch is used for diving (about two hours a week), it will run for about one
month (until NG is indicated).
How to use this watch properly
It is recommended that you charge the watch everyday.
To insure that this watch demonstrates its depth meter function and chronograph
function besides the timekeeping function, always keep it sufficiently charged.
If the watch is not sufficiently charged or the power is very low, the depth meter
function and chronograph function cannot be activated.
The watch is protected from overcharge.
For charging the watch, expose the solar cell (the face of the watch) to light.
11

12
Safety Precautions (Instructions to be followed at all times).................... 2
1. NAMES OF PARTS ................................................................................ 14
2. WARNING FUNCTIONS OF THIS ECO-DRIVE WATCH ....................... 16
Charge level indication/Insufficient charge warning function/
Stop warning function/Time reset warning function/
Overcharge prevention function
3. TIME REQUIRED FOR CHARGING ...................................................... 24
4. PRECAUTION FOR THIS ECO-DRIVE WATCH .................................... 26
5. SWITCHING BETWEEN MODES .......................................................... 28
6. ADJUSTING TIME AND DATE (Time mode) ........................................ 30
7. DIVE MODE............................................................................................ 34
8. CHRONOGRAPH MODE ....................................................................... 38
9. TROUBLESHOOTING............................................................................ 41
10. SETTING FUNCTION HAND AT “0” POSITION.................................... 46
CONTENTS

13
11. ALL RESET/ADJUSTING HAND POSITION......................................... 48
12. NOTE ON RECHARGEABLE CELL...................................................... 50
13. OTHER FUNCTIONS.............................................................................. 51
Rotating bezel/No decompression limits
14. PROPER CARE FOR LONG TERM USE .............................................. 54
15. SPECIFICATIONS .................................................................................. 61

Name Time mode Dive mode Chronograph mode
(A): Button (A) To be pressed for selecting a mode
(B): Button (B) To be pressed for showing the maximum depth
left in the memory or for actuating the chronograph.
1:
Function hand Indicates charging level. Indicates depth. Indicates second(s).
2: Mode hand Stops at DV position. Stops at DV position. Indicates minute(s).
3: Hour hand Always indicates the time (hour).
4: Minute hand Always indicates the time (minute).
5: Second hand Always indicates the time (second).
6: 24-hour hand Always indicates the time in the
24-hour system synchronized with the hour hand.
7: Calendar Always indicates the date.
8: Crown To be used for adjusting the time or date.
14
1. NAMES OF PARTS
Collate the following table with the watch diagram on the first page.

a: Charge levels (LV1, LV2,NG) ......Charge level of the watch is indicated as
follows (LV.1, LV.2, NG) by the function
hand. These guidelines indicate whether
the depth meter function is usable or not.
b: Overzone mark ...........................When the diving depth exceeds 50 meters
(125 feet) or there is something abnormal
in the depth meter function, the function
hand points to the overzone mark.
c: Depth meter scale.......................The diving depth is indicated by the
function hand on this depth meter scale.
d: Pressure sensor..........................Measures the depth by sensing the water
pressure.
e: Water sensor ..............................When the water sensor gets wet, the
watch is automatically shifted to the dive
mode.
f: Rotating bezel.............................The diver can know the elapsed time of
diving by using this rotating bezel.
g: Solar cell.....................................Electric energy necessary for running the
watch is generated by this solar cell when
it is exposed to enough light for charging.
15

16
Function hand: Points at
LV.2, LV.1 or NG.
Function hand: Points at NG.
[Insufficient charge warning indication]
2 second interval
movement
1 second
interval
movement
[Normal indication (Time mode)]
As the charge
declines:
As the watch is
recharged:
2. WARNING FUNCTIONS OF THIS ECO-DRIVE
WATCH
With decline of the charge of the watch, its warning function is activated to
change the indication.

17
When the watch is sufficiently charged and the time is correctly set:
[Time reset warning indication]
Function hand: Points at “0”.
[Stop warning indication]
Function hand: Points at “0”.
Mode hand: Points at “0”.
As the watch is
recharged:
Irregular 2
second interval
movement
As the charge
declines
furthermore: