Citizen F990 Instructions Download Page 4

Checking and adjusting the leap second setting

• The leap second setting is adjusted automatically but it can be adjusted 

manually.

You can find a list of leap seconds at the homepage of IERS (INTERNATIONAL 

EARTH ROTATION & REFERENCE SYSTEMS SERVICE).

http://hpiers.obspm.fr/eop-pc/earthor/utc/TAI-UTC_tab.html

1. 

Change the mode to [

SET

] and push the crown in to position 

2

.

The second hand stops.

2. 

Press and hold the upper right button 

B

 for 2 seconds or more.

Using the “0:00:00” position as the starting point, the minute and second 

hands indicate the leap second setting.

When the leap second setting is 

“-37 seconds”

When the leap second setting is 

“-65 seconds”

RX

-TM

E

RX-G

PS

ON

ALM

OFF

NO

OK

ALM

UTC

LLI

TME

SET

CHR

24

12

02

14

04

16

06

18

08

20

10

22

ON

SM

T

OFF

SM

T

F

E

S

M

W F

T

T S

60

30

50

10

20

40

60

30

0

–1

–2

–3

–4

–5

–6

–7

+1

+2

+3

+4

+5

+5

.5

+6

+7

+8

+9

+9.

5

+10

+11

+12

+13

+14

–12

–11

–10

–9

–8

LON PAR

ATN

RUH

DXB

KH

I

DE

L

DA

C

BK

K

BJ

S

TY

O

AD

L

SYD

NOU

AKL

TBU

MDY

HN

L

AN

C

LA

X

PDL

FEN

RIO

MA

O

NY

C

CH

I

DE

N

7

RX

-TM

E

RX-G

PS

ON

ALM

OFF

NO

OK

ALM

UTC

LLI

TME

SET

CHR

24

12

02

14

04

16

06

18

08

20

10

22

ON

SM

T

OFF

SM

T

F

E

S

M

W F

T

T S

60

30

50

10

20

40

60

30

0

–1

–2

–3

–4

–5

–6

–7

+1

+2

+3

+4

+5

+5

.5

+6

+7

+8

+9

+9.

5

+10

+11

+12

+13

+14

–12

–11

–10

–9

–8

LON PAR

ATN

RUH

DXB

KH

I

DE

L

DA

C

BK

K

BJ

S

TY

O

AD

L

SYD

NOU

AKL

TBU

MDY

HN

L

AN

C

LA

X

PDL

FEN

RIO

MA

O

NY

C

CH

I

DE

N

7

The hands point to “0 minute 37 

seconds”.

The hands point to “1 minute 5 

seconds”.

3. 

Turn the crown to adjust the setting if the leap second is not 

correct.

• Adjustable range is from 0 to ‒90 seconds.

4. 

Push the crown in to position 

0

.

5. 

Change the mode to [

TME

] to finish the procedure.

F990 Abbreviated instruction

Adjusting the time and calendar manually

You can set the time and calendar of the home time manually.
• Execute world time setting beforehand following “Setting the world time 

manually”.

• The time of the local time is corrected automatically following its time zone 

setting after setting the home time manually.

1. 

Change the mode to [

SET

] and push the crown in to position 

2

.

The second hand stops.

2. 

Press and hold the lower right button 

A

 for 2 seconds or 

more.

The minute hand slightly moves and time and calendar become adjustable.

3. 

Press and release the lower right button 

A

 repeatedly to 

change the hand/indication to be corrected.

• Each time you press button 

A

, the target changes as follows:  

 Hour and minute

 → 

date

 → 

year/month

 → 

day of week

 → (back to the top)

• The hands and indications slightly move when selected to show they 

become adjustable.

4. 

Rotate the crown to adjust the hand/indication.

• Hour, minute and date move synchronously. Take care the time set is AM 

or PM. Change of date indication shows it just became AM.

• Date indication changes to the next as the function indication rotates 5 

times.

• When you rotate the crown quickly a few times, the hand/indication will 

move continuously. To stop the rapid movement, rotate the crown in either 

direction.

• Year and month are indicated with the second hand.

12

1

2

3

4

5

6

7

8

9

10

11

“Month” corresponds to one of 

the 12 zones shown in the figure 

below.

Each number means month.

The year corresponds to the 

years since leap year and is 

indicated with the position of the 

second hand.

Years since leap year:  

0

 (Leap 

year)

0

Years since leap year:  

1

1

Years since leap year  

2

2

3

Years since leap year:  

3

5. 

Repeat steps 3 and 4.

6. 

Push the crown in to position 

0

 in accordance with a reliable 

time source.

The second hand starts moving from 0 second.

7. 

Change the mode to [

TME

]  to finish the procedure.

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