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

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.

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

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

BATTERY SR927SW

0022230

BATTERY CLAMP SCREW

4225571

BATTERY CLAMP

0022459

CIRCUIT BLOCK COVER SCREW

4457980

CIRCUIT BLOCK COVER

4224514

CONDUCTING PLATE

0396580

FRICTION SPRING FOR

SECOND COUNTING

4000664

CIRCUIT BLOCK

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

4002700

COIL BLOCK (A)

4002700

STOPWATCH COIL BLOCK FOR

SECONDS

0391591

TRAIN WHEEL SETTING LEVER

4239710

ROTOR STATOR

4002711

STOPWATCH COIL BLOCK FOR

10 MINUTES

4002711

STOPWATCH COIL BLOCK FOR

MINUTES

4239712

ROTOR STATOR FOR

CHRONOGRAPH FOR

10 MINTUES

4450701

SWITCH LEVER FOR RESET

BUTTON

4239713

ROTOR STATOR FOR

CHRONOGRAPHMINUTES

0100559

MAIN PLATE

46 4450703

SWITCH LEVER FOR

START/STOP BUTTON

0383592

SETTING LEVER

49 0351583

SETTING STEM

0384582

YOKE

0281580

SETTING WHEEL

4239717

ROTOR STATOR

FOR CHRONOGRAPH SECOND

[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

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