Seiko 7S25B Installer manual

PARTS CATALOGUE/TECHNICALGUIDE
Cal. 7S25B, 7S35B, 7S55B
[SPECIFICATIONS]
1/8
21,600 Hz/hour (6 beats per second)
4.9 mm
(x 1.5)
Ø 27.4 mm
Ø 27.0 mm
lAutomatic winding
lDate calendar
lDate correction function
l
3 hands (hour, minute and second hands)
7S25B :21 jewels
7S35B, 7S55B :23 jewels
SEIKO
7S25B 7S35B 7S55B
Cal. No.
Item
Movement
Movement
size
Time indication
Outside diameter
Casing diameter
Height
Additional mechanism
Vibration per hour
Jewels
Brand
7S25A/ 7S35A/ 7S55A 7S25B/ 7S35B/ 7S55B
Refer to “PARTS CATALOGUE/
TECHNICAL GUIDE
Cal. 7S25A,7S35A,7S55A.”
Refer to “PARTS CATALOGUE/
TECHNICAL GUIDE
Cal. 7S25B,7S35B,7S55B.”
These sections are
different from A Cal.
* Cal.7S watches are changed
from caliber “A” to caliber “B”
in October 2006 production.
According to the change, we
would like you to pay attention
to the design of the balance
s t af f w h e n repa iri ng th o s e
watches.
The difference between A
Cal.and B Cal.
function
Number of jewels

Cal. 7S25B, 7S35B, 7S55B
PARTS CATALOGUE
Disassembling procedures Figs.: 1 
rj
Reassembling procedures Figs.:
rj
1
Lubricating: Types of oil Oil quantity
AO-3 (Moebius A) Liberal quantity
SEIKO Watch Oil S-6 Normal quantity
SEIKO Watch Oil S-4 Small quantity
qf
Dial holding spacer
4408 ***
qa
Date driving wheel
0802 300
q; Intermediate date
driving wheel and pinion
0817 300
qg
Lower bridge for third wheel and
pinion screw
0012 420
qh
Lower bridge for third
wheel and pinion
0436 300
qd Cannon pinion
qs
Minute wheel and pinion
0261 006
3Date dial guard screw A (3 pics)
0012 354
4Date dial guard screw B (1 pic)
0016 705
5Date dial maintaining plate
0808 030
1Hour, minute, and second hand
2Dial
6Date dial
0878 ***
9Hour wheel
0271 483 8Day-date corrector setting
transmission wheel
0737 300
7Date jumper
0810 030
2/8
For parts 6
and qf
, refer to “ PARTS USED DIFFER DEPENDING ON THE CASING MODEL” on page 5.
*Parts qg
and qh
are only used in the
7S35 and 7S55 watches.
Diashock

PARTS CATALOGUE Cal. 7S25B, 7S35B, 7S55B
ql
Second reduction wheel and pinion
0514 002
ws
Balance complete
without stud
0310 197
wj
Ratchet wheel
0285 013
wl
Barrel and train wheel bridge
0112 300
wf
Pallet cock
0161 300
wd
Pallet cock screw
0012 354
wa
Balance cock
0171 197
wh
Ratchet wheel screw
0012 919
w k
Barrel and train wheel bridge
screw
0012 420
qj
Oscillating weight (with
ball bearing)
0509 188(7S25B)
0509 196(7S35B)
0509 198(7S55B)
q k
Second reduction wheel and
pinion screw 0012 539
wg
Pallet fork
0301 009
w ;
Balance cock screw
0012 420
3/8
eaFirst reduction wheel
0511 006
esPawl lever
0831 004
e; Reduction wheel holder
0836 002
Diafix
For parts qj , ql , wl ,
e;
, and
ea
, refer to “REMARKS ON DISASSEMBLING AND REASSEMBLING” on page 6.
For parts w;
, wa, and ws
refer to “HOW TO REMOVE AND INSTALL THE BALANCE STAFF ” on page 7.
For parts
rj
, refer to “ PARTS USED DIFFER DEPENDING ON THE CASING MODEL ” on page 5.
rj Winding stem
0351 ***
edClick
0381 004
efFourth wheel & pinion
0241 010
egBarrel complete (with mainspring)
0201 024
ehThird wheel & pinion
0231 070 (7S25B)
0231 007 (7S35B, 7S55B)
ekCenterwheel bridge screw
0012 354
ejEscape wheel & pinion
0251 013
r;Centerwheel & pinion (with
cannon pinion ) 0224 078
elCenterwheel bridge
0122 300
raYoke spring screw
0012 168
rdYoke
0384 070
rfSetting lever
0383 070
rgClutch wheel
0282 070
rhIntermediate wheel for calendar
corrector
0962 008
rsYoke spring
0388 070
Diashock

Cal. 7S25B, 7S35B, 7S55B
PARTS CATALOGUE
Parts name Parts code Parts name Parts code
Upper hole jewel frame for diashock
0014 295
Upper hole jewel frame for third
wheel and pinion 0015 701
Lower hole jewel frame for diashock Upper hole jewel frame for escape
wheel and pinion 0015 711
Diashock upper frame 0014 573 Upper spring for third wheel and pin-
ion 0015 703
Diashock lower frame 0014 574 Upper spring for escape wheel and
pinion
Diashock upper spring
0014 577
Regulator 0341 020
Diashock lower spring Stud support 0345 197
SCREW PARTS
4/8
Parts code Parts name Parts code Parts name
Ratchet wheel screw
0012 919
0012 539
0012 354
0016 705
0012 420
0012 168
Second reduction wheel and
pinion screw
Date dial guard screw B
Center wheel bridge screw
Pallet cock screw
Date dial guard screw A
Balance cock screw
Barrel and train wheel
bridge screw
Lower bridge for third
wheel and pinion screw
Yoke spring screw

TECHNICAL GUIDE Cal. 7S25B, 7S35B, 7S55B
PARTS USED DIFFER DEPENDING ON THE CASING MODEL
6Date dial
0878 ***
*The date dial used differs depending on the casing model.
qf
Dial holding spacer
4408 ***
The dial holding spacer for a diver’s watch has an identifying mark.
Identifying mark
4408 170 4408 171
* The dial holding spacer used differs depending on the casing model. Refer to "SEIKO Watch
Parts Catalogue (SEIKO WATCH SERVICE SITE)."
rj Winding stem
0351 ***
* The winding stem used differs depending on the casing model. Refer to "SEIKO Watch Parts
Catalogue (SEIKO WATCH SERVICE SITE)."
5/8

TECHNICAL GUIDE Cal. 7S25B, 7S35B, 7S55B
I. REMARKS ON DISASSEMBLING AND REASSEMBLING
l
The following description is only applicable to 7S caliber watches.
qj
Oscillating weight (with ball bearing)
The inside screw can be found in the inside ring
of the ball bearing. Use the big screwdriver to
screw sufficiently tight. When setting the oscil-
lating weight, align the hole of the first reduction
wheel with the hole of the balance cock, and then
set the oscillating weight by tightening the inside
screw of the inside ring of the ball bearing (refer
to the right figure).
First reduction
wheel
Balance cock
ql
Second reduction wheel and pinion
wl
Barrel and train wheel bridge
Before setting the barrel and train wheel bridge, set the first reduction wheel and arbor,
pawl lever, and reduction wheel holder.
e; Reduction wheel holder
How to disassemble How to assemble
eaFirst reduction wheel
Liberally lubricate the first reduction wheel
(refer to the right figure).
6/8
Lubricate the second reduction wheel and pinion
(refer to the right figure).

TECHNICAL GUIDE Cal. 7S25B, 7S35B, 7S55B
w ;
- ws
:HOW TO REMOVE AND INSTALL THE BALANCE STAFF
How to remove How to install
1. Initial phase
Set the balance complete with stud and balance cock to
the main plate.
2. Move the stud support toward the balance cock until it is
attached to the balance cock.
* When doing so, make sure that the outer end of the
hairspring is not removed from the regulator arm.
3. Using sturdy tweezers, push the stud outward from the
direction of the arrow shown in the illustration until it is
removed from the stud support.
4. Remove the balance co ck and re place t he b al an ce
complete with stud with a new one.
3. Temporarily set the stud to the stud support.
Make sure that the hairspring passes outside the pin of
the regulator arm.
* Be careful so as not to damage the hairspring.
1. Initial phase
Set a new balance complete with stud to the main plate.
2. Set the balance cock and tighten the balance cock screw.
4. Using sturdy tweezers, set the stud to the stud support
and press it down.
Make sure that the outer end of the hairspring passes
through the regulator slot of the regulator arm.
* Be careful so as not to damage the hairspring.
7/8

TECHNICAL GUIDE Cal. 7S25B, 7S35B, 7S55B
HOW TO ADJUST THE HAIRSPRING
1. Names of the parts
A: Stud
B: Regulator arm
C: Regulator pin
D: Stud support
2. Rota te B to f ine -t une th e
position of the outer end of
the hairspring which passes
through the regulator slot so
that the hairspring makes the
longest diameter.
3. Rota te A to f ine -tune the
position of the outer end of
the hairspring so that the
hairspring passes through
the center of the regulator
slot.
4. Rota te B to f ine -t une th e
e f f e c t i v e l e n g t h o f t h e
ha ir sp rin g wh ic h pa sse s
through the regulator slot to
define adequate clearance.
Maximum
clearance
Minimum
clearance
23 4
Adjust the position of the hair-
spring so that it passes through
the center of the regulator slot.
Stud Stud support
Regulator arm
Regulator pin
To adjust the length of the
hairspring, rotate the regu-
lator pin only counterclock-
wise (as indicated with the
arrow). While doing so,
make sure that the hair-
spring does not lean to one
side.
Move the stud support to cor-
rectly position the roller jewel. Adjust the location of the regula-
tor arm to fine-tune the length of
the hairspring.
Rotate the Regulator pin to adjust the
clearance to control the swing angle
of the hairspring.
8/8
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