Seiko 8T67A Installer manual

PARTS CATALOGUE / TECHNICAL GUIDE
Cal.8T67A
8T67A
Driving system Step motor 2 pieces
Additional function
Crown Normal position Free
operation 1st click position Date setting (clockwise)
2nd click position Time setting, Resetting the circuit
Loss/Gain (Monthly rate) Less than 15 seconds at normal temperature range
Frequency of crystal oscillator 32,768 Hz
Operational temperature range
-5℃~ +50℃
Regulation system Nil
Gate time for rate measurement Use 10-second gate
Current consumption
Coil resistance
・4002054（Coil block A): 1.45 - 1.65KΩ for chronograph 
・4002055（Coil block B): 1.65 - 1.85KΩ for time display
Power Battery No.
SR936SW (Silver oxide battery)
supply Battery voltage
1.55V
Battery life Approximately 3 years
Jewels
0 jewel
1/20
Cal. No.
Item
・Stopwatch function up to 12 hours in 1/5 second
・Date display with quick correction.
・Energy depletion forwarding function
(The second hand moves at two-second intervals.)
・Movement: Less than 2.7μA
・Circuit block: Less than 0.7μA
Movement Size
・Outside diameter: 30.8 mm
・Casing diameter 29.0 mm
・Height：5.1 mm
・3 Hands: Hour, Minute, and 1/5 second chronograph hand
・Small Second : Small second hand(6H), Minute chronograph hand (12H),
Hour chronograph hand(9H)

PARTS CATALOGUE
8T67A
Type of oil Oil quantity mark
AO-3(Moebius A）
NORMAL QUANTITY
AO-2(Moebius F) SUFFICIENT QUANTITY
S-6
0012 354
Date indicator maintaining plate screw
0808 052
Date indicator maintaining plate
Date indicator
0810 019
Date jumper
0806 002
Date corrector wheel
Intermediate date wheel and pinion
Date Indicator driving wheel
2/20
[ Cross section ]
5
6
0817 048
7
0802 039
1
2
3
Refer to page 7 for each parts code.
4
Disassembling procedures Figs.
1
→
62
Reassembling procedures Figs.
62
→
1
*1
*1
0103 448
Main plate

PARTS CATALOGUE
8T67A
0273 *** Refer to page 8 for each parts code.
Hour wheel
0012 354
Switch lever holder screw
0837 005
Switch lever holder
4450 017
Switch lever A
4450 018
Switch lever B
0962 891
0962 013
3/20
8
9
11
12
14
Date corrector setting
transmission wheel C
13
Date corrector setting
transmission wheel B
10

PARTS CATALOGUE 8T67A
0016 121
Switch spring screw
0016 121
Switch spring screw
16 4250 ***
Switch spring
Refer to page 8 for each parts code
and page 12 for spring setting position.
0353 018
Second counting wheel friction spring
0190 007
Chronograph bridge
0587 006
Refer to page 12 for 0581 007
spring setting position. Chronograph coupling lever
Refer to page 12 for
21
0585 013 spring setting position.
Hammer
Refer to page 10 for
oiling spot and page 12
for spring setting position.
0894 002
Train wheel stop lever
0888 *** Refer to page 12 for
Second countingwheel spring setting position.
Refer to page 8 for
each parts code.
23 0902 ***
Minute counting wheel
Refer to page 8 for
each parts code.
0587 004
Hammer operating lever A
Refer to page 12 for
24 0902 *** spring setting position.
Hour counting wheel
Refer to page 8 for
each parts code.
4/20
Hammer operation lever B
15
15
17
18
20
19
25
22
26
*1
*2
*1
*2

PARTS CATALOGUE 8T67A
0016 121
0186 002
Lower plate for chronograph bridge
Refer to page 10 for
oiling spot.
4408 149
Circuit block spacer
4004 352
0125 318
Circuit block
Train wheel bridge
4270 336
Battery connection (-)
*㉝～㊳
Refer to page 9 for assembling
of chronograph wheel.
0885 003
0012 354
0886 004
Coil block screw
4002 054
Coil block A
0886 005
4146 063
Step rotor
4239 063
0701 015
Stator A
Fifth wheel and pinion
5/20
38
0885 004
Hour counter intermediate
wheel and pinion A
42
43
36
Counter intermediate
wheel and pinion
40
37
Minute counter intermediate
wheel and pinion A
41
Hour counter intermediate
wheel and pinion C
35
Second counter intermediate
wheel and pinion
39
34
0885 005
Hour counter intermediate
wheel and pinion B
31
33
0885 006
32
27
28
Lower plate for chronograph bridge screw
29
30
*1
*1

PARTS CATALOGUE 8T67A
0231 059
Third wheel and pinion
4455 006
0144 002
Reset lever
Fourth wheel and pinion
0261 126
0391 028
Minute wheel and pinion Train wheel setting lever
0281 452
0012 354
Setting wheel
Coil block screw
4002 055
4283 042
Coil block B
4146 063
Step rotor
0221 ***
Refer to page 8 for
4239 064
each parts code. Stator B
0383 891
0701 015
0384 024
Yoke
0240 ***
Second wheel
0282 452
Refer to page 8 for Clutch wheel
each parts code.
0962 032
0351 177
Winding stem
6/20
45
44
46
47
55
51
48
52
Center wheel and pinion
53
49
Center wheel and pinion bridge
54
50
57
61
62
Date corrector
setting transmission
wheel A
60
58
Setting lever
56
Fifth wheel and pinion
59
*1
*1

PARTS CATALOGUE 8T67A
●Tools and consumables required for disassembling/reassembling
・Movement Holder
UNIVERSAL MOVEMENT HOLDER (S-682)
・Watch oils
SEIKO watch oil AO-2, AO-3 and S-6
AO-2 AO-3
S-6
7/20

TECHNICAL GUIDE 8T67A
Remarks:
●How to find the correct parts, if not determined by 4 digit caliber number.
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.
Caliber code
8T6720A 8T6740A
No Parts name Parts code Parts code
⑧
Hour wheel
0273 038 0273 042
⑯
Switch spring
4250 088 (marking "2")
4250 090 Marking "4"
㉒Second counting wheel 0888 028 0888 029
㉓Minute counting wheel 0902 017 0902 018
㉔Hour counting wheel 0902 017 0902 018
㊿Center wheel and pinion 0221 087 0221 092
Second wheel 0240 018 0240 019
③Date indicator
Parts code
Crown Date Color of Color of
position Position figure background
0878 328 3H 3H Black White
0878 329 3H 3H White Black
* All parts code are subject to change without notice.
8/20
5
REMARKS ON DISASSEMBLING AND REASSEMBLING THE MOVEMENT

TECHNICAL GUIDE 8T67A
●How to assemble chronograph wheel
There is a mark on parts. Parts are set in order of the mark as shown in the table below.
Image example of the mark
Mark
Parts name
A38 Hour counter intermediate wheel and pinion A
B37 Minute counter intermediate wheel and pinion A
C36 Counter intermediate wheel and pinion
Nil
35 Second counter intermediate wheel and pinion
D34 Hour counter intermediate wheel and pinion B
E33 Hour counter intermediate wheel and pinion C
9/20
34
Hour counter intermediate
wheel and pinion B
35
Second counter intermediate
wheel and pinion
33
Hour counter intermediate
wheel and pinion C
36
Counter intermediate
wheel and pinion
38
Hour counter
intermediate
wheel and pinion A
37
Minute counter
intermediate
wheel and pinion A

TECHNICAL GUIDE
8T67A
Type of oil Oil quantity mark
AO-3(Moebius A）
NORMAL QUANTITY
AO-2(Moebius F) SUFFICIENT QUANTITY
S-6
●Remarks for the lubrication
Hammer
Lower plate for chronograph bridge
Note:
*1: Lubricate on the pointed spot.
16
Switch spring
Oiling spot and spring setting position are below;
Chronograph coupling lever
Hammer operating lever B
Setting position
Switch spring
10/20
16
*Lubricate on the contact spot of the spring and the pin.
21
19
20
27
*1 *1
*2
*3
*2
*3
*1
*1

TECHNICAL GUIDE 8T67A
3.Spring setting position Train wheel stop lever
Lower plate for chronograph bridge
Hammer operating lever A
Hammer
Hammer operating lever B Chronograph coupling lever
4.Switch lever A and B setting position
Switch spring
Switch spring
Switch lever BSwitch lever A
Hammer operating lever A
Chronograph coupling lever
11/20
Setting position
19
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.
16
16
12
11
26
25
28
26
21
20
19
*4
*1
*2
*3
*1
*2
Enlarged view
*1
*2
*1 *2
*3
*4

TECHNICAL GUIDE 8T67A
●How to remove the Winding Stem
1) Set the winding stem to normal position (=0).
2) Pull out the Crown with winding stem,
while pushing "A" carefully.Push "A"
●How to remove or install the Battery
1) Remove the hook of the Switch Spring's Battery Clamp as illustrated in the drawing 1).
2) Insert the battery sideways as illustrated in the drawing 2) , and have the hook of
the Switch Spring's Battery Clamp catch the main plate.
Switch spring
Battery clamp
1) Removing Main plate 2) Installing
●Remarks on installing the Battery
After replacing the battery with a new one,
or reinstalling, be sure to touch the AC Tweezers
terminal of circuit block and the switch spring
with conductive tweezers to reset the circuit
as illustrated.
12/20
16

●How to install Chronograph hands
Place the movement on the movement holder.
Be careful not to apply a strong pressure to the movement
(1) Push button A ( Chronograph start )
(2) Push button A ( Chronograph stop )
(3) Push button B ( Chronograph reset )
(4) After (1)-(3), Install the chronograph hands at the positions
as shown below;
Second chronograph "12" o'clock of the center dial
Minute chronograph
"60" minute of the sub dial at 12h position
Hour chronograph "12" hour of the sub dial at 9h position
*Once the chronograph hands are detached, the reuse of them is not available.
Please replace them with new hands.
●How to check the hands setting
*The hand's top surface should be set perpendicular with the axis tip , as shown below.
*1 Second chronograph hand
*2 Minute / Hour chronograph hands and Small second hand and 24 hour hand
13/20
TECHNICAL GUIDE
8T67A
Movement holder
Button A
( Chronograph start /
Button B
( Chronograph reset )

TECHNICAL GUIDE 8T67A
●How to measure the current consumption for the whole movement
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 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” ).
*When measuring the current consumption using the SEIKO
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.
14/20
REMARKS ON INSPECTION AND MEASUREMENT

TECHNICAL GUIDE 8T67A
〔STRUCTURE OF THE CIRCUIT BLOCK〕
●Value checking -coil reistance (coil block)
Check the resistance of each coil block if they are within the range in the following table.
COIL BLOCK (A) 4002054 1.45 - 1.65KΩ
COIL BLOCK (B) 4002055 1.65 - 1.85KΩ
15/20
Output terminal
(Hand moving)
Crystal unit
C-MOC-IC
Input terminal
Output terminal
(CG)
Input terminal (-)

TECHNICAL GUIDE 8T67A
*5
*3 *2 *7
*1 *9
*11
*10
*6 *8
*4
Note
*1:
Hour hand
*5: Chronograph minute hand *9: Crown at normal position
*2:
Minute hand
(60 minute) *10:
Crown at first position
*3: Chronograph second hand *6: Chronograph hour hand (Date setting)
*4: Small second hand (12 hour) *11:
Crown at second position
*7:
Button A (START / STOP)
(Time setting)
*8: Button B (RESET)
1.How to set the time
1) Pull out the crown to the second click position.
2) Turn the crown to set hour and minute hands.
(Check that AM / PM is set correctly.)
3) Push the crown back into the normal position.
[ Note ]
2.How to set the date
1) Pull out the crown to the first click position.
2) Turn the crown clockwise for date setting.
*Do not set the date between 9:00 P.M. and 3:00 A.M. as this will cause a malfunction.
3) Push the crown back into the normal position.
3.How to reset (after battery change)
It is possible to reset by the following two methods.
1) Set the crown to the normal position.
Method 1
2) Touch the AC terminal of circuit block and the switch spring with conductive tweezers
to reset the circuit.
3) The small second hand will move at two-second interval for 10 seconds.
1) Pull out the crown to the second click position.
Method 2
2) Press the button B for two seconds and release the button.
3) Push the crown back to the normal position.
4) The small second hand will move at two-second interval for 10 seconds.
* If the crown is operated within this 10 seconds, the two-second interval movement will not activate.
[ Note ]
It is not necessary to set the chronograph hands after the battery is exchanged.
If the chronograph hands position are incorrect, following below procedure all the chronograph hands
will be reset to "0" position.
16/20
DISPLAY AND CROWN / BUTTON OPERATION
If the crown is pulled to the second position while the chronograph is started, the chronograph hands
will continue to move. This is not a malfunction.
Button A
(START)
Button A
(STOP)
Button B
(RESET)

TECHNICAL GUIDE 8T67A
[ Standard measurement ]
Showing the measurement result：
6 hours 20 minutes 10 seconds
・Press button A to start the
・Press button A again to stop the ・Press button B to reset the
chronograph. chronograph. chronograph.
The chronograph second The chronograph hands stop to All the chronograph hands
hand will start moving. indicate the elapsed time. will be reset to "0" position.
Note
The chronograph can measure up to 12 hours.
The chronograph stops after a measurement for 12 hours.
*Restart in the following procedure.
*During the chronograph operation, button B (reset) can be pushed. There is no problem with the function.
[ Accumulated elapsed time measurement ]
A / A ･･･
B
Showing the measurement result：
Showing the measurement result：
1 hour 8 minutes 40 seconds
6 hours 20 minutes 10 seconds
*Restart and stop of the chronograph can be repeated as many times as necessary by pressing button A
17/20
Press the buttons in the following order :
A
A
START
RESET
RESET
Button B
(RESET)
Button A
(START)
START
STOP (Finish)
STOP / RESTART
STOP
HOW TO USE THE CHRONOGRAPH
Press the buttons in the following order :
A
A
B

TECHNICAL GUIDE 8T67A
●Water resistance test
Check the water resistance according to the designated specification of the watch
Marking on the case back Test method 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 DIVERIS （AIR DIVERIS）150 m 18.75 BAR ＝150(m)times 0.125
SCUBA DIVERIS (AIR DIVERIS)200 m
25 BAR ＝200(m)times 0.125
He-GAS DIVERIS 300 m
37.5 BAR ＝300(m)times 0.125
He-GAS DIVERIS 600 m
75 BAR ＝600(m)times 0.125
He-GAS DIVERIS1000m
125 BAR ＝1000(m)times 0.125
18/20
Condensation test
Condensation test
Water pressure test
Air leak test
Water pressure test
Condensation test

TECHNICAL GUIDE 8T67A
Symptom Possible causes Solutions
Movement The watch stops operating. The battery has been depleted.
Measure the battery voltage.
Replace the battery with a new
one.
The hour wheel and the pinion of Check the relevant parts, and
the minute wheel are not properly replace the damaged parts with
engaged. (Or the teeth of the hour new ones.
wheel and/or minute wheel have
been broken.)
The hooking portions of the Securely attach the hooks of the
circuit block cover are not circuit block cover to the main
properly engaged, resulting in plate.
poor conductivity.
The coil is broken. Measure the coil block resistance.
Replace the coil with a new one.
One or more wheels have been Remove dirt or dust and clean the
contaminated with dirt, dust or contaminated wheels. Be careful
other particles. so as not to damage the teeth of
the plastic parts while cleaning.
An excessive amount of oil in the
movement has caused adhesive
forces among the parts. (wringing)
The current consumption Dirt, dust or foreign particles are Remove dirt, dust or foreign
for the whole movement adhered to the movement. particles and clean the movement.
exceeds the standard The driving pulse is generated in If the current consumption for
value. order to compensate the excessive the circuit block alone is within
load applied to the wheels. (The the standard value range,
oil has deteriorated, leaked or run overhaul and clean the movement
out.) parts, and then make the
measurement again.
The current consumption The light f rom out side the Shut out the light, and make the
for the circuit block alone movement is affecting the measurement again.
exceeds the standard measurement.
value. There is a defect in the IC Replace the circuit block with a
( integrated circuit ) . new one.
19/20
TROUBLESHOOTING

TECHNICAL GUIDE
8T67A
Symptom Possible causes Solutions
STOPWATCH One or more STOPWATCH The relevant coil is broken. Measure the coil block resistance.
hands have stopped moving Replace the coil with a new one if
or show an abnormal move- necessary.
ment. An excessive load is being Clean the relevant parts and
applied to the chronograph lubr icate with an adequate
wheels due to dust or foreign amount of oil.
par ticles adhering to them or
oil starvation.
The step motor shows an There is a crack on the circuit Replace the circuit block with a
abnormal movement. block switch pattern. new one.
The step motor has been deformed. Replace the stator with a new
one.
The buttons do not operate The amount of oil around the Clean the buttons and lubricate
normally. buttons is insufficient. appropriately.
The circuit block pat tern has Adjust the circuit block pattern
been broken or bent. or replace the circuit block with a
new one.
Exterior The crown falls off. The winding stem is not securely Check the main plate, winding
Parts installed. (The setting lever and stem, set ting lever and yoke.
yoke are disengaged.) Replace the defective parts with
new ones.
The current consumption An excessive load is being Adjust or remount the relevant
exceeds the standard value. applied due to friction among hands.
the hour, minute and STOP-
WATCH hands.
Small amount of water/ Water resistance is deteriorated. Investigate the causes to take
blur inside of the glass The watch has been subjected to necessary measures , while
persists. water pressure that exceeds the cleaning inside of the watch.
guaranteed degree.
20/20
TROUBLESHOOTING