Seiko 6T63A, 8T63A Technical Manual

PARTS CATALOGUE / TECHNICAL GUIDE

Cal. 6T63A

[SPECIFICATIONS]

Cal. No.

Item

Interval of hands movement

Driving system

Additional function

Loss/gain

Regulation system

Gate time for rate measurement

Power

supply

Battery No.

Battery voltage

Battery life

Number of jewels

1/19

Crown

operation

Normal position

1st click position

2nd click position

Current consumption

Coil resistance

1 second

0 jewel

Stepping motor, 2 pieces

• Stopwatch function

60-minute stopwatch in one second increments.

• Second hand stop function

4002054 (COIL BLOCK A)

1.45 - 1.65 K

Ω

Use 10-second gate.

SEIKO SR936SW

Nil

1.55 V

Approx. 3 years

6T63A

• 3 hands (hour, minute, and

small second hand)

• 24 -hour indicator

• Date indicator

4002055 (COIL BLOCK B)

1.65 - 1.85 K

Ω

Free

Date setting(clockwise)

Time setting, hand position adjustment / resetting the circuit

Monthly rate: Less than 20 seconds (worn on the wrist at the tempera-

ture between 5 and 35)

• Diameter

Outside: Ø 30.8 mm Casing: Ø 29.0 mm

• Height: 5.1 mm

Movement : Less than 2.70 μA
Circuit block: Less than 0.70 μA

SPECIFICATIONS

2/19

Cal. 6T63A

Cal. 6T63A has a new structure employing one crown and two buttons. The construction of chronograph
mechanism is based on Cal. 8R28 mechanical chronograph watch by using the one-piece 3 pointed reset
hammer. While other Swiss-made watches are using separate hammers which require an assembly and
adjustment of the hammers, the one-piece hammer design realizes maximum durability and stability of
the component and easier maintenance. It is also equipped with the self-alignment function for all counting
hands to return to zero positions instantaneously.

This is the multi-display analogue watch featuring a stopwatch function.

●

The time is indicated by the 24-hour, hour and minute hands, and a small second hand.

●

The stop watch can measure up to 60 minutes in one second increments. After 60 minutes,

it will stop automatically.

● Measurement performance

Displays the elapsed time with the 2 designated STOPWATCH hands.

Measures up to 60 minutes in one second increments.

● Button operation (Crown position: Normal position)

Button A: START/STOP
Button B: RESET

1. STOPWATCH FUNCTION

Cal . 6T63A

a b c

Hour hand

Minute hand

STOPWATCH 1/5-second hand

STOPWATCH minute

hand

Small second hand

a: Normal position
b: First click
c: Second click

24-hour hand

A

B

CROWN

When pushin g th e re se t bu tton

the HAMMER OPERATING LEVER

B moves automatically to
ke ep ap propr iate bal ance of th e

HAMMER position.

CHRONOGRAPH

COUPLING LEVER

HAMMER OPERATING

LEVER A

HAMMER OPERATING

LEVER B

HAMMER HAMMER

HAMMER OPERATING

LEVER B

FE ATUR ES

START

RESET

SPECIFICATIONS

3/19

Cal. 6T63A

After installing the battery, pull out the crown to the second click position. And then follow the
instructions below to correct the hand positions and set the time.

NECESSARY PROCEDURE AFTER BATTERY CHANGE

Pull out to the second click position when the small second hand is at
the 60 seconds position. The small second hand stops on the spot.

Crown

Push back in to the normal position in accordance with a time signal.

Crown

Watch starts moving with 2-second interval for 10 seconds. Wait until it moves with
1-second interval.*
* Do not move the crown before it ends.

Button B

Press Button B for longer than 2 seconds.
The STOPWATCH minute hand turns a full circle.

● Standard measurement

Button A

START

→

Button A

STOP

→

Button B

RESET

● A ccumulated elapsed time measurement

Button A

START

→

Button A

STOP

Button A

STOP

→

Button B

RESET

→

Button A

RESTART

…→

Restart and stop of the stopwatch can be repeated by pressing button A.

●

Measurement functions

Accumulated elapsed time measurement and split time measurement are available.

Cal. 6T63A

PARTS LIST

4/19

DAT E I NDI CATOR
MAINTAINING
PL AT E SC REW
0012354

1

2

3

4

5

6

7

DAT E I NDI CATOR
MAINTAINING
PL AT E
0808052

DATE DIAL
0878***

DAT E J UM PER
0810019

DATE CORRECTOR

WHEEL

0806002

INTERMEDIATE

SMALL HOUR HAND WHEEL

AND PINION
0817048

SMALL HOUR HAND WHEEL

0157***

[ Cross section ]

7

3

For parts and , please refer to the page 10.

Disassembling procedures Figs. : 1 61

Reassembling procedures Figs. : 61 1

AO-2

Type of oil Oil quantity mark

NORMAL QUANTITY

AO-3

S-6

LIBERAL QUANTITY

SMALL QUANTIT Y

Cal. 6T63A

PARTS LIST

5/19

HOUR WHEEL

0273***

8

9

SWITCH LEVER
HOLDER SCREW

012354

10

11

12

14

13

SWITCH LEVER
HOLDER

0837005

SWITCH LEVER A

4450017

SWITCH LEVER B

4450018

DATE CORRECTOR
SETTING
TRANSMISSION

WHEEL B

0962013

DATE CORRECTOR
SETTING TRANSMISSION

WHEEL C

0962891

For parts , please refer to the page 10.

8

Cal. 6T63A

PARTS LIST

6/19

*1

*1

*2

*2

15

SWITCH SPRING SCREW

0016121

17

SECOND COUNTING

WHEEL FRICTION

SPRING
0353018

18

CHRONOGRAPH

BRIDGE
0190007

16

SWITCH SPRING

4250***

19

CHRONOGRAPH

COUPLING LEVER
0581007

25

TRAIN WHEEL

STOP LEVER
0894002

26

HAMMER OPERATING

LEVER A
0587004

20

HAMMER OPERATING

LEVER B
0587006

HAMMER

0585013**

15

SWITCH SPRING SCREW

0016121

21

SECOND
COUNTING

WHEEL

0888***

22

POSITIONING
ARBOR
0685002

23

MINUTE
COUNTING

WHEEL

0740***

24

For parts , please refer to the page 10 and 11.

For parts and , please refer to the page 10.

For parts , , , , and , please refer to the page 12 and 13.

22

16

25 26

24

2019 21

Cal. 6T63A

PARTS LIST

7/19

For parts , please refer to the page 12 and 13.

27

LOWER PLATE FOR

CHRONOGRAPH BRIDGE SCREW

0016121

28

LOWER PLATE FOR

CHRONOGRAPH BRIDGE

0186002

29

CIRCUIT BLOCK SPACER
44 0814 9

30

CIRCUIT BLOCK
4004253

31

BATTERY CONNECTION (-)
4270336

35

SECOND COUNTER

INTERMEDIATE WHEEL

AND PINION
0885003

38

COIL BLOCK SCREW
0012354

39

COIL BLOCK A
4002054

40

STEP ROTOR
4146063

41

STAT OR A
4239063

34

MINUTE COUNTER

INTERMEDIATE WHEEL

AND PINION B
0886006

36

COUNTER

INTERMEDIATE WHEEL

AND PINION
0886004

37

MINUTE COUNTER

INTERMEDIATE WHEEL

AND PINION A
0886005

42

FIFTH WHEEL AND

PINION
0701015

32

TRAIN WHEEL BRIDGE

0125316

33

MINUTE COUNTER

INTERMEDIATE WHEEL

AND PINION
0886007

*1

28

Cal. 6T63A

PARTS LIST

8/19

43

RESET LEVER
4455006

50

TRAIN WHEEL

SETTING LEVER
0391028

51

COIL BLOCK SCREW
0012354

52

COIL BLOCK B
4002055

53

STEP ROTOR
4146063

54

STAT OR B
4239064

57

SETTING
LEVER
0383891

58

YOKE
0384024

60

CLUTCH
WHEEL

0282452

61

DATE CORRECTOR
SETTING
TRANSMISSION

WHEEL A

0962012

59

WINDING STEM
0351177

44

THIRD WHEEL

AND PINION
0231043

45

FOURTH WHEEL

AND PINION
0144 002

46

MINUTE WHEEL

AND PINION
0261026

47

SETTING WHEEL

0016121

48

CENTER WHEEL AND

PINION BRIDGE
0016121

49

CENTER WHEEL

AND PINION
0221***

55

FIFTH WHEEL

AND PINION
0701015

56

SECOND WHEEL

0240***

*1

*1

49 56 59

For parts , and , please refer to the page 10.

Cal. 6T63A

PARTS LIST

9/19

●

Tools and consumables required for disassembling/reassembling

• Movement holder

UNIVERSAL MOVEMENT HOLDER (S-682)

• Watch oils

SEIKO watch oil AO-3 (or Moebius A) and AO-2 (or Moebius F)

AO-3

AO-2

S-6

TECHNICAL GUIDE

Cal. 6T63A

10/19

●

How to find the correct parts, if not determined by 4 digit caliber number

Following par ts are determined based on the design of watches, such as hands height, dial

color, and design of cases. Please refer to the SEIKO WATCH PARTS CATALOGUE in order to

choose corresponding parts.

3

DATE DIAL 0878***

59

WINDING STEM 0351177

* For screw down crown models, the stem is assembled to the crown and is not available

separatelly

7

SMALL HOUR HAND WHEEL

8

HOUR WHEEL

16

SWITHCH SPRING

22

SECOND COUNTING WHEEL

24

MINUTE COUNTING WHEEL

49

CENTER WHEEL AND PINION

56

SECOND WHEEL

Please refer to the following table in order to find the correct part number of each wheel

according to the hand installation height. The numeral 2 or 4 is printed on the DIAL.

7 SMALL

HOUR HAND

WHEEL

8 HOUR

WHEEL

16 SWITHCH

SPRING

22 SECOND

COUNTING

WHEEL

24 MINUTE

COUNTING

WHEEL

49 CENTER

WHEEL AND

PINION

56 SECOND

WHEEL

2

0157012 0273038 4250035 0888017 0740002 0221087 0240018

4

0157013 0273042 4250054 0888019 0740003 0221092 0240019

TECHNICAL GUIDE

Cal. 6T63A

11/19

Push the "A" on the SETTING LEVER

gently(refer to the pic ture on the
right) in order to disengage it from
the SETTING STEM. Then pul out
the crown with the stem completely.
FOR UNIT'S DIGIT properly.

REMARKS ON DISASSEMBLING AND REASSEMBLING THE MOVEMENT

●

How to remove the SETTING STEM before dismantling the movement

Crown position: normal (=0) position.

A

●

How to remove or install the battery

1) Remove the hook of the switch spring's battery clamp.

2) Insert the battery sideways, and have the hook of the switch spring's battery clamp catch the
main plate.

Battery clamp

Main plate

1) When Removing

2) When Installing

16 Switch spring

●

Remarks on installing the battery

1) Af ter t he bat t er y is re plac e d
battery is reinstalled following
the repairing procedures, be
sure to touch the AC terminal
of circuit block and the switch
spring with conductive tweezers
to reset the circuit as illustrated.

Tweezers

TECHNICAL GUIDE

Cal. 6T63A

12/19

●

Remarks for the lubrication

Hammer

21

There must be oil within the range of the arrow.

Lower plate for chronograph bridge

28

Note

*1: Oiling should be done on the

pointed spot of marked place.

*1

*1

*1 *1

Switch spring

*Oiling spot and spring set ting position.

16

*2

*3

*3

*2

Chronograph coupling lever

19

Setting position

Switch spring

16

*Oiling should be done on the contact spot of the spring and the pin.

Hammer operating lever B

20

AO-2

Type of oil

Oil quantity mark

NORMAL QUANTITY

AO-3

S-6

LIBERAL QUANTITY

SMALL QUANTIT Y

TECHNICAL GUIDE

Cal. 6T63A

13/19

●

Remarks for setting position of the spring of chronograph function

Lower plate for
chronograph bridge

28

Hammer operating

lever A

26

Train wheel stop lever

25

Chronograph coupling
lever

19

Hammer operating

lever B

20

Hammer

21

*2

*3

*4

*1

*1

*2

*3

*4

Setting position

●

Remarks for setting position of the SWITCH LEVER A and B

*1 *2

Chronograph
coupling lever

Hammer operating

lever A

Switch spring

Switch lever B

Switch lever A

Switch spring

*2

*1

Enlarged view

Switch lever B is set between the switch
spring and hammer operating lever A .

Switch lever A is set between the switch

spring and chronograph coupling lever.

TECHNICAL GUIDE

Cal. 6T63A

14/19

REMARKS ON INSPECTION AND MEASUREMENT

1. To measure the current consumption for the whole move-

ment, connect the ( -) probe to the battery connection ( -)
and (+) probe to the other metal part of the movement,
such as battery clamp or circuit block cover.

* When measuring the current consumption using the

SEIKO digital multi-tester (S-860), use the range of 40 μ
A of SUPPLY V (= 1.55 V) & GATE TIME (2 S).

2. Connect the AC component to the positive terminal for 2

seconds until a short circuit occurs to reset the integrated
circuit.

3. After the integrated circuit is reset, wait approximately for

10 seconds until a stable measurement is obtained, and
then read the measurement.

4. Make sure the read value is less than 2.7 μ A.

●

How to measure the current consumption for the whole movement

●

How to measure the current consumption for the CIRCUIT BLOCK alone

1. To measure the current consumption for the CIRCUIT
BLOCK alone, connect each probe to the appropriate
positive (+) or negative (- ) input terminal of the CIR­CUIT BLOCK (please refer to “Structure of the CIRCUIT
BLOCK” below) .

* When measuring the current consumption using the SEI-

KO Multi-Tester S-860, use the range of 4 μ A of SUPPLY
V (= 1.55 V) & GATE TIME (2 S).

2. Repeat the same procedures as 2. and 3. of measuring
current consumption for the whole movement above.

* When measuring the current consumption for the circuit

block alone, be careful not to damage or deform the pat­tern of the circuit block.

3. Make sure the read value is less than 0.7 μ A.

TECHNICAL GUIDE

Cal. 6T63A

15/19

●

Value checking – coil resistance (coil blocks)

Check the resistance of each coil block if they are within the range in the following table.

1.45 KΩ ~ 1.65 K

Ω

1.65 KΩ ~ 1.85 K

Ω

COIL BLOCK (A)

COIL BLOCK (B)

4002054

4002055

[Structure of the CIRCUIT BLOCK]

Input terminal (+)

Input terminal (-)

Output terminal(hand moving)

Crystal unit

Output terminal(CG)

C=MOS=IC

TECHNICAL GUIDE

Cal. 6T63A

16/19

Operation

Function

Checkpoint

Pull out the crown
to the 2nd click
and push it back
in to the normal
position. Repeat
the same several
times.

Setting mechanism

- switching the
function of the time
setting

Make sure that it
has a click at each
position and the
stem is not pulled
off.

Pull out the
crown to the 1st
click, then turn it
clockwise.

Hands installation

Make sure that the
hour and minute
h a n d s m o v e
smoothly (without
touching each other
of touching the
surface of the dial or
inside of the glass).

Make sure that
the day changes
smoothly.

Calendar mechanism

- correcting the day

Make sure that the
date changes when
the hour and minute
hands pass around
midnight.

Calendar mechanism

- date change

●

Function check

Press button A
to start the stop­watch.

Press button A
again to stop the
stopwatch.

Press button B
to reset the stop­watch.

Stopwatch
mechanism

Make sure that the
Stopwatch hands
start/stop smoothly.

Make sure that the
Stopwatch hands
are reset to the
“0” position.

Pull out the crown
to the 2nd click,
then turn it.

Setting mechanism

- hour and minute
hand setting

A

B

A A B
Start Stop Reset

TECHNICAL GUIDE

Cal. 6T63A

17/19

●

Water resistance test

Check the water resistance according to the designated specification of the watch.

Marking on the case back Tes t met hod Applied pressure

WATER RESISTANT (WATER RESIST) 3 BAR

WATER RESIST 5BAR 5 BAR

WATER RESIST 10BAR 10 BAR

WATER RESIST 15BAR 15 BAR

WATER RESIST 20BAR 20 BAR

SCUBA DIVER'S (AIR DIVER'S) 150 m

18.75 BAR = 150 (m) times 0.125

SCUBA DIVER'S (AIR DIVER'S) 200 m 25 BAR = 200 (m) times 0.125

He-GAS DIVER'S 300 m 37.5 BAR = 300 (m) times 0.125

He-GAS DIVER'S 600 m 75 BAR = 600 (m) times 0.125

He-GAS DIVER'S 1000 m 125 BAR = 1000 (m) times 0.125

Air leak test

Condensation test

Condensation test

Water pressure test

Water pressure test

Condensation test

TECHNICAL GUIDE

Cal. 6T63A

18/19

Movement

TROUBLESHOOTING

The watch stops operating. The battery has been depleted.

Measure the bat tery voltage.
Replace the battery with a new
one.

The hour wheel and the pinion of
the minute wheel are not properly
engaged. (Or the teeth of the hour
wheel and/or minute wheel have
been broken.)

Check the relevant parts, and
replace the damaged parts with
new ones.

The hooking por tions of the
circuit block cover are not
properly engaged, resulting in
poor conductivity.

Securely attach the hooks of the
circuit block cover to the main
plate.

The coil is broken.

Measure the coil block resistance.
Replace the coil with a new one.

One or more wheels have been
contaminated with dir t, dust or
other particles.

An excessive amount of oil in the
movement has caused adhesive
forces among the parts. (wringing)

Remove dir t or dust and clean the
contaminated wheels. Be careful
so as not to damage the teeth of
the plas tic par ts while cleaning.

The current consumption
for the whole movement
exceeds the standard
value.

Dirt, dust or foreign particles are
adhered to the movement.

Remove dir t, dus t or foreign
particles and clean the move­ment.

The driving pulse is generated in
order to compensate the excessive
load applied to the wheels. (The
oil has deteriorated, leaked or run
out.)

If the current consumption for
the circuit block alone is within
the standard value range,
overhaul and clean the move­ment parts, and then make the
measurement again.

The current consumption
for the circuit block alone
exceeds the standard
value.

The light from outside the
movement is affecting the
measurement.

Shut out the light, and make the
measurement again.

There is a defec t in the IC
(integrated circuit).

Replace the circuit block with a
new one.

Symptom Possible causes Solutions

TECHNICAL GUIDE

Cal. 6T63A

19/19

ST OP WATC H

One or more STOP-

WATCH hands have

stopped moving or show
an abnormal movement.

The relevant coil is broken.

Measure the coil block resistance.
Replace the coil with a new one if
nece ss ar y.

An excessive load is being
applied to the chronograph
wheels due to dust or foreign
particles adhering to them or
oil starvation.

Clean the relevant parts and
lubricate with an adequate
amount of oil.

The step motor shows an
abnormal movement

.

There is a crack on the circuit
block switch pattern.

Replace the circuit block with a
new one.

The but tons do not operate
normally.

The amount of oil around the
buttons is insufficient.

Clean the buttons and lubricate
appropriately.

The circuit block pat tern has
been broken or bent.

Adjust the circuit block pattern
or replace the circuit block with a
new one.

The crown falls off.

The winding stem is not securely
installed. (The setting lever and
yoke are disengaged.)

Check the main plate, winding
stem, setting lever and yoke.
Replace the defective parts with
new ones.

The current consumption
exceeds the standard value.

An excessive load is being
applied due to friction among
the hour, minute and STOP-

WATCH hands.

Small amount of water/
blur inside of the glass
persists.

Water resistance is deteriorated.
The watch has been subjected to
water pressure that exceeds the
guaranteed degree.

Investigate the causes to take
necessary measures, while
cleaning inside of the watch.

Replace the stator with a new
one.

Adjust or remount the relevant
hands.

Symptom

Possible causes

Solutions

Exterior
parts

The step motor has been deformed.

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