Seiko 7T85 Quick start guide

PARTS LIST/TECHNICALGUIDE
Double Retrograde Chronograph Cal. 7T85
[SPECIFICATIONS]
1/17
Movement
Item Cal. No. 7T85A
0 jewel
Stepping motor, 4 pieces
• Battery life indicator (The small second hand moves at two-sec-
ond intervals.)
• Date correction function
• Second hand stop function
• Electronic circuit reset function
Monthly rate: Less than 15 seconds (worn on the wrist at
temperature range between 5 ºC and 35 ºC)
Use 10-second gate.
SEIKO SR927SW
Nil
1.55 V
Approx. 3 years
• STOPWATCH functions
100-minute stopwatch in 1/5-second increments, consecutively
measurable up to 300 minutes (5 hours)
Accumulated Elapsed Time Measurement
Split Time Measurement
STOPWATCH hand position adjustment
1 second
4002700, 2 pieces: 2.10 – 2.70 KΩ
1. Coil block for hour, minute, and small second
2. Coil block for stopwatch second
4002711, 2 pieces: 1.80 – 2.40 KΩ
1. Coil block for stopwatch minute
2. Coil block for stopwatch 10 minute
Circuit block: Less than 0.30 μA
Movement: Less than 1.10 μA
Date setting (clockwise)
Time setting, hand position adjustment / resetting the circuit
Free
55
50
45
40
35
Outside: Ø 27.6 mm Casing:Ø 27.0 mm
• Diameter
• Height: 3.3 mm
• 3 hands (hour, minute,
and small second hands)
• Calendar (date: date dial)
7T85A
Battery No.
Driving system
Additional function
Crown operation
Loss/Gain
Regulation system
Gate time for rate measurement
Current consumption
Power supply
Battery life
Number of jewels
Interval of hands movements
Normal position
1st click position
2nd click position
Coil resistance
Battery voltage

SPECIFICATIONS
2/17
2. RESETTING THE CIRCUIT
Cal. 7T85A has a new structure employing one crown and two buttons, but the basic movement
structure of Cal. 7T85A is similar to the previous Cal. 7T Series watches, and the knowledge and
technique you have gained in handling the previous Cal. 7T Series watches will come in handy
when you repair Cal. 7T85A.
When repairing, however, you are requested to have full knowledge of the features characteristic
of these watches and strictly observe the repairing and checking instructions provided in this
guide so that the watches will be repaired correctly.
FEATURES
Cal. 7T85A
Double Retrograde Chronograph
●Measurement performance
Displays the elapsed time with the 3 designated STOPWATCH hands.
Measures up to 109 minutes 59.8 seconds in 1/5-second increments.
●Button operation (Crown position: Normal position)
Button A: START/STOP
Button B: SPLIT/SPLIT RELEASE/RESET
●Measurement functions
Accumulated elapsed time measurement and split time measurement are available.
1. STOPWATCH FUNCTION
When an abnormal display appears, reset the built-in integrated circuit. The watch will resume its
normal operation.
 ● Button operation (Crown position: Second click)
Press and hold buttons A and B at the same time for longer than 2 seconds.
55
50
45
40
35
Hour hand
Small second hand
STOPWATCH 10-minute hand
Minute hand
STOPWATCH 1-minute hand STOPWATCH 1/5-second hand
Button A
Crown
Button B

SPECIFICATIONS
3/17
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 2nd click when the small second hand is at the
12 o’ clock position.
Turn to set the main time.
* Check that AM/PM is correctly set.
Pull out the crown to the 2nd click.
Press and hold both buttons A and B at the same time for longer than 2 seconds.
Button A
Crown
Crown
Note*
Push back in to the normal position in accordance with a time signal.
Crown
Note* Pressing Button A for longer than 2 seconds here will allow you to resume the procedure again
as indicated by the arrow if neccessary.
Button B
Button A
Button B
Button A
Button B
Press Button A for longer than 2 seconds.
The STOPWATCH 1-minute hand turns a full circle.
Press Button B to set the STOPWATCH 1-minute hand
to the “0” position.
Press Button A for longer than 2 seconds.
The STOPWATCH 1/5 second hand turns a full circle.
Press Button B to set the STOPWATCH
1/5 second hand to the “0” position.
Press Button A for longer than 2 seconds.
The STOPWATCH 10-minute hand turns a full circle.
Press Button B to set the STOPWATCH 10-minute hand to
the “0” position.
3. Resetting stopwatch hands to “0” positions
2. Resetting the circuit
1. Main time setting

Cal. 7T85A
PARTS LIST
4/17
Lubricating of some parts is shown in “REMARKS ON DISASSEMBLING AND REASSEMBLING.”
2 0808580
DATE DIAL GUARD
3 0808527
DATE DIAL
4 0962580
CALENDAR CORRECTOR
SETTING TRANSMISSION
WHEEL
5 0737580
CALENDAR CORRECTOR
WHEEL
6 0802580
DATE DRIVING WHEEL
7 0271588
HOUR WHEEL
1 0027973
PIN FOR DATE DIAL GUARD
[CALENDAR MECHANISM]
Disassembling procedures Figs. : 1 54
Reassembling procedures Figs. : 54 1
Remarks on removing the SETTING STEM
To remove the SETTING STEM when taking out the movement
from the case or while disassembling the parts during repair
work, be sure to pull out the crown to the first click, and then, re-
move the SETTING STEM while pushing the setting lever. Refer
to page 9 for further details.
* For the type of oil and quantity of lubrication, refer to the following TECHNICAL GUIDE section.

PARTS LIST Cal. 7T85A
5/17
Lubricating of some parts is shown in “REMARKS ON DISASSEMBLING AND REASSEMBLING.”
[BATTERY AND ELECTRONC CIRCUIT ]
4259509
ANTI MAGNETIC SHIELD
8
BATTERY SR927SW
9
0022230
BATTERY CLAMP SCREW
10
4225571
BATTERY CLAMP
11
0022459
CIRCUIT BLOCK COVER SCREW
12
4457980
CIRCUIT BLOCK COVER
13
4224514
CONDUCTING PLATE
14
0396580
FRICTION SPRING FOR
SECOND COUNTING
15
4000664
CIRCUIT BLOCK
16
0022459
CIRCUIT BLOCK
COVER SCREW
( 3 pcs.)
0022230
BATTERY CLAMP
SCREW (3 pcs.)

Cal. 7T85A
PARTS LIST
6/17
Lubricating of some parts is shown in “REMARKS ON DISASSEMBLING AND REASSEMBLING.”
21 0885590
SECONDS COUNTER
1ST INTERMEDIATE WHEEL
22 0885591
SECONDS COUNTER 2ND
INTERMEDIATE WHEEL
23 0950590
MINUTES COUNTER
INTERMEDIATE WHEEL
24 0270582
MINUTES COUNTING WHEEL
27 0240580
SMALL SECONDS WHEEL
29 0701580
FIFTH WHEEL & PINION
32 4283581
SPACER FOR CENTER
WHEEL & PINION
34 4146710
STOPWATCH ROTOR FOR
SECOND
35 4146710
STOPWATCH ROTOR
FOR MINUTES
25 0950590
10 MINUTES COUNTER
INTERMEDIATE WHEEL
26 0270582
10 MINUTES COUNTING WHEEL
28 0241583
FOURTH WHEEL & PINION
30 0231580
THIRD WHEEL & PINION
31 0261580
MINUTE WHEEL
33 0221583
CENTER WHEEL & PINION
36 4146710
STOPWATCH ROTOR FOR
10 MINUTES
17 4270710
BATTERY CONNECTION(-)
18 0027974
PIN FOR TRAIN WHEEL
BRIDGE
19 0125509
TRAIN WHEEL BRIDGE
20 0888582
SECOND COUNTING
WHEEL
37 4146710
ROTOR
[GEAR TRAIN MECHANISM]

PARTS LIST Cal. 7T85A
7/17
Lubricating of some parts is shown in “REMARKS ON DISASSEMBLING AND REASSEMBLING.”
0282585
CLUTCH WHEEL
48
4002700
COIL BLOCK (A)
41
4002700
STOPWATCH COIL BLOCK FOR
SECONDS
38
0391591
TRAIN WHEEL SETTING LEVER
44
4239710
ROTOR STATOR
53
4002711
STOPWATCH COIL BLOCK FOR
10 MINUTES
40
4002711
STOPWATCH COIL BLOCK FOR
MINUTES
39
4239712
ROTOR STATOR FOR
CHRONOGRAPH FOR
10 MINTUES
52
4450701
SWITCH LEVER FOR RESET
BUTTON
47
4239713
ROTOR STATOR FOR
CHRONOGRAPHMINUTES
51
0100559
MAIN PLATE
54
46 4450703
SWITCH LEVER FOR
START/STOP BUTTON
0383592
SETTING LEVER
45
49 0351583
SETTING STEM
0384582
YOKE
43
0281580
SETTING WHEEL
42
4239717
ROTOR STATOR
FOR CHRONOGRAPH SECOND
50
[SETTING MECHANISM/
STEPPING MOTORS
(STATORS AND COIL
BLOCKS)]

Cal. 7T85A
PARTS LIST
8/17
●How to find the correct parts, if not determined by 4 digit caliber number
●Tools and consumables required for disassembling/reassembling
Following parts 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.
 ✳ HOLDING RING FOR DIAL (0866788)
3 DATE DIAL (0878***)
49 SETTING STEM (0351583)
● How to discriminate resembled parts
Refer to the illustrations below to see the difference between those two types of pins.
1 PIN FOR DATE DIAL GUARD
0027973
18 PIN FOR TRAIN WHEEL BRIDGE
0027974
• Movement holder
UNIVERSAL MOVEMENT HOLDER
(S-682)
• Watch oils
SEIKO watch grease (S-6) and watch oils (AO-3 and AO-2)
S-6 AO-2
AO-3

TECHNICAL GUIDE Cal. 7T85A
9/17
REMARKS ON DISASSEMBLING AND REASSEMBLING THE MOVEMENT
●How to remove the SETTING STEM before dismantling the movement
●Setting mechanism
• Setting position and lubricating
46 SWITCH LEVER FOR START/STOP BUTTON
45 SETTING LEVER
43 YOKE
44 TRAIN WHEEL SETTING LEVER TRAIN WHEEL SETTING LEVER
YOKE
SETTING LEVER
SWITCH LEVER
AO-3 (or MS-A)
SEIKO Watch Oil S-6
48 SETTING STEM
Crown position: 1st click position
Push the SETTING LEVER gently (refer to the picture on the
right) in order to disengage it from the SETTING STEM. Then
pull out the crown with the stem completely.

TECHNICAL GUIDE Cal. 7T85A
10/17
●Gear train mechanism
• Setting position and lubricating
33 CENTER WHEEL
& PINION
0221583
32 SPACER FOR
CENTER WHEEL
& PINION
4283581
21 SECONDS
COUNTER 1ST
INTERMEDIATE
WHEEL
0885590
22 SECONDS
COUNTER 2ND
INTERMEDIATE
WHEEL
0885591
24 MINUTES
COUNTING
WHEEL
0270582
35 STOPWATCH
ROTOR FOR
MINUTES
4146710
23 MINUTE COUNTER
INTERMEDIATE
WHEEL
0950590
34 STOPWATCH
ROTOR FOR
SECONDS
4146710
20 SECONDS
COUNTING
WHEEL
0888582
27 SMALL SECONDS
WHEEL
0240580
29 FIFTH WHEEL &
PINION
0701580
37 ROTOR
4146710
28 FOURTH WHEEL &
PINION
0241583
25 10 MINUTES
COUNTER
INTERMEDIATE
WHEEL
0950590
36 STOPWATCH
ROTOR FOR
10 MINUTES
4146710
31 MINUTE WHEEL
0261580
30 THIRD WHEEL
& PINION
0231580
26 10 MINUTES
COUNTING
WHEEL
0270582

TECHNICAL GUIDE Cal. 7T85A
11/17
33 CENTER WHEEL & PINION
20 SECONDS COUNTING
WHEEL
Upper pivot of the ROTOR
Upper pivot of the MINUTE WHEEL
Other portions
36
35
34
37
27
26
20
31
• 36 STOP WATCH ROTOR FOR 10 MINUTES,
37 ROTOR, 34 STOPWATCH ROTOR FOR
SECONDS, 35 STOPWATCH ROTOR FOR
MINUTES (as illustrated below)
•31 M I N U T E W H E E L , 2 6 10 M I N U T E S
COUNTING WHEEL, 20 SECONDS COUNTING
W H EEL a n d 2 7 S M A L L SEC O ND S ( a s
illustrated below)
After setting the 19 TRAIN WHEEL BRIDGE and 18 PIN FOR TRAIN WHEEL BRIDGE as illustrated below.
lubricate the upper pivots of the following parts:

TECHNICAL GUIDE Cal. 7T85A
12/17
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 1.10 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 CIR-
CUIT 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 pat-
tern of the circuit block.
3. Make sure the read value is less than 0.30 μ A.
[Structure of the CIRCUIT BLOCK]
Input terminal (+)
Input terminal (-)

TECHNICAL GUIDE Cal. 7T85A
13/17
●Value checking – coil resistance (coil blocks)
Check the resistance of each coil block if they are within the range in the following table.
2.10 KΩ~ 2.70 KΩ
2.10 KΩ~ 2.70 KΩ
1.80 KΩ~ 2.40 KΩ
1.80 KΩ~ 2.40 KΩ
COIL BLOCK (A)
STOPWATCH COIL BLOCK FOR SECONDS
STOPWATCH COIL BLOCK FOR MINUTES
COIL BLOCK FOR STOPWATCH 10-MINUTE
4002700
4002700
4002711
4002711

TECHNICAL GUIDE Cal. 7T85A
14/17
●Function check
Before doing the following function check, follow the instructions on P.3 to correct the hand
positions, set the time and operate the stopwatch function.
55
50
45
40
35
Operation Function Check point
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 func-
tion of the time set-
ting
Make sure that it has a
click at each position
an d t he s te m is no t
pulled off.
55
50
45
40
35
Pull out the crown to
the 1st click, then turn
it.
C a l e n d a r m e c h a -
ni sm - cor rec ti ng
the date if available
Make sure that the date
changes smoothly.
55
50
45
40
35
Pull out the crown to
the 2nd click, then turn
it.
Second hand stop
func t ion (i f ava il -
able)
Make sure that the sec-
ond hand stops when
the crown is pulled out
to the 2nd click.
Setting mechanism
- hour and minute
hand setting
M a k e s u r e t h a t t h e
hour and minute hands
move smoothly (with-
o u t t o u c h i n g e a c h
other or touching the
surface of the dial or
inside of the glass).
Hands installation
C a l e n d a r m e c h a -
nism - date change
Make sure that the date
changes when the hour
and minute hands pass
around midnight.
55
50
45
40
35
A
B
<Standard Measurement>
Press button A to stop the
stopwatch.
Press button B to reset the
stopwatch.
A A B
Start Stop Reset
Stopwatch mecha-
nism
<Split Time Measurement>
A B B A B
Start Split Split Stop Reset
Release
M a k e s u r e t h a t t h e
Stopwatch hands start/
stop smoothly.
M a k e s u r e t h a t t h e
Stopwatch hands are
reset to the “0” posi-
tion.

TECHNICAL GUIDE Cal. 7T85A
15/17
●
Water resistance test
●
Accuracy test
Check the water resistance according to the designated specification of the watch.
Measure the rate and make sure the value shows within ±0.50 s/d.
Use 10 seconds gate of the tester.
Water resistance test
WATER RESIST 5 BAR
WATER RESIST 10 BAR
WATER RESIST 15 BAR
WATER RESIST 20 BAR
WATER RESISTANT (WATER RESIST)
Marking on the case back
Air overpressure test
W a te r o v e r pr e s s u r e
test and condensation
test
Water-t igh tn es s and
w a t e r o v e r p r e s s u r e
test and condensation
tests before/after water
overpressure test
SCUBA DIVER’S (AIR DIVER’S) 150 m
SCUBA DIVER’S (AIR DIVER’S) 200 m
He-GAS DIVER’S 300 m
He-GAS DIVER’S 600 m
He-GAS DIVER’S 1000 m
18.75 BAR = 150 (m) times 0.125
25 BAR = 200 (m) times 0.125
37.5 BAR = 300 (m) times 0.125
75 BAR =600(m)times 0.125
125 BAR = 1000 (m) times 0.125
3 BAR
5 BAR
10 BAR
15 BAR
20 BAR
Applied pressure

TECHNICAL GUIDE Cal. 7T85A
16/17
Movement
TROUBLESHOOTING
The watch stops operat-
ing.
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 prop-
erly 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 portions of the cir-
cuit block cover are not properly
engaged, resulting in poor con-
ductivity.
Securely attach the hooks of the
circuit block cover to the main
plate.
The coil is broken. Measure the coil block resist-
ance. Replace the coil with a new
one.
One or more wheels have been
contaminated with dirt, dust or
other particles.
An excessive amount of oil in the
movement has caused adhesive
forces among the parts. (wring-
ing)
Remove dirt or dust and clean the
contaminated wheels. Be careful
so as not to damage the teeth of
the plastic parts while cleaning.
The current consumption
for the whole movement
e x c e e d s t h e s t a n d a r d
value.
Check the rotation and engage-
ment of the date dial.
bend the date dial downward to
adjust the clearance. Or replace
the date dial with a new one.
Dirt, dust or foreign particles are
adhered to the movement.
Remove dirt, dust or foreign par-
ticles and clean the movement.
The driving pulse is generated in
order to compensate the exces-
sive 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, over-
haul and clean the movement
parts, and then make the meas-
urement again.
The current consumption
for the circuit block alone
exceeds the standard val-
ue.
The light from outside the move-
ment is affecting the measure-
ment.
Shut out the light, and make the
measurement again.
There is a defect in the IC (inte-
grated circuit).
Replace the circuit block with a
new one.
The DATE DIAL shows an
abnormal movement.
The DATE DIAL has become im-
properly engaged with the date
driving w he el or dis en gaged
from the date driving wheel.
The date does not change. The date jumper has been disen-
gaged.
Symptom Possible causes Solutions
The d ate dial does not
move.

TECHNICAL GUIDE Cal. 7T85A
17/17 Copyright©2008 by
STOPWATCH
O n e o r m o r e S T O P -
W AT C H h a n d s h a v e
stopped moving or show
an abnormal movement.
The relevant coil is broken. Measure the coil block resist-
ance. Replace the coil with a new
one if necessary.
An excessive load is being ap-
plied to the chronograph wheels
due to dust or foreign particles
adhering to them or oil starva-
tion.
Clean the relevant parts and lu-
bricate 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 buttons do not oper-
ate normally.
The amount of oil around the but-
tons is insufficient.
Clean the buttons and lubricate
appropriately.
The c ircuit bloc k pattern 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, set ting lever and yoke.
Replace the defective parts with
new ones.
The current consumption
exceeds the standard value.
An excessive load is being ap-
plied due to friction among the
hour, minute and STOPWATCH
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 clean-
ing inside of the watch.
Replace the stator with a new
one.
Adjust or remount the relevant
hands.
Symptom Possible causes Solutions
Exterior
parts
The s tep motor ha s been de -
formed.