Seiko 4205B Quick start guide

1
PARTS CATALOGUE /TECHNICAL GUIDE
Cal. 4205B / 4206B / 4207B
4208B / 4225A / 4227A
Movement
Time indication
Outside diameter ø17.5 mm
Casing diameterMovement size ø17.2 mm
Height 5.6 mm
Three hands (Hour, minute and second hands)
Vibrations per hour 21,600 (6 beats per second)
Additional
mechanism
Automatic winding
Jewels 17 jewels 21 jewels
The illustrations refer to Cal. 4206B (x 2.0)
4227A4207B4205B
Cal. No.
Item
[SPECIFICATIONS]
Date calendar
Day and date calendar
Instant calendar (date)
setting device
Instant calendar (day
and date) setting device
4206B 4225A
4208B
ø23.8 mm
ø23.4 mm
5.6 mm
Auxiliary hand winding
mechanism
17 jewels 21 jewels 21 jewels 21 jewels

2
PARTS CATALOGUE
30 0310 421
Balance complete
with stud
28 0012 123
Stud screw
29 0171 426
Balance cock
27 0012 484
Balance cock screw
Diashock
26 0505 421
Transmission wheel
and pinion
25 0831 421
Pawl lever with jewel
23 0012 485
Framework for automatic
device screw
Disassembling procedures Figs. : 1 ~ 61
Reassembling procedures Figs. : 61 ~ 1
Lubricating: Type of oil Oil quantity
Moebius A or AO-32Liberal quantity
SEIKO Watch Oil S-4 Normal quantity
SEIKO Watch Oil S-6 Extremely small
20 Cannon pinion
19 0802 422
Date driving wheel
18 0817 421
Intermediate date driving
wheel and pinion
17 0261 422
Minute wheel
16 Hour wheel
15 0972 423
Day-date corrector finger
14 0810 420
Date jumper
13 0811 420
Date jumper spring
12 Date dial
11 0808 423
Date dial guard
10 0873 422
Day jumper
9 0012 485
Date dial guard screw
8 0012 797
Day jumper screw
7 0556 422
Date finger
6 0012 485
Date driving wheel
screw
5 Day star with dial disk
3 Holding ring for dial
2 Dial
1 Hour, minute and
second hands
21 0012 488
Oscillating weight
without pinion screw
Cal. 4205B, 4206B, 4207B, 4208B, 4225A, 4227A
4 0963 420
Snap for day star with
dial disk
22 0500 424
Oscillating weight
24 0193 420
Framework for automatic
device with ball bearing
Ex.: Cal. 4206B
33 0301 422
Jewelled pallet fork
and staff
32 0161 420
Pallet cock
31 0012 485
Pallet cock screw
Please see the remarks on the following pages.
➡➡

3
PARTS CATALOGUE
61 Main plate
0100 421 (4205B/4206B)
0100 423 (4207B/4208B)
0100 430 (4225A/4227A)
Diashock
60 Winding stem
59 0283 421
Winding pinion
58 0282 422
Clutch wheel
57 0390 420
Setting lever axle
56 0383 420
Setting lever
55 0384 420
Yoke
54 0388 421
Setting lever
spring
53 0012 484
Setting lever
spring screw
Dial leg pin
51 0251 421
Escape wheel and
pinion
50 0121 420
Center wheel bridge
0540 421
Dial leg holder
49 0012 485
Center wheel
bridge screw
48 0105 420
Lower plate for
balance cock
47 0542 421
Locking seat for idle
wheel
45 0363 420
Sliding crown
wheel spring
46 0237 421
Intermediate
ratchet wheel
44 0012 484
Screw for locking
seat for idle wheel
43 0241 421
Fourth wheel and
pinion
41 Second wheel
pinion
42 0231 421
Third wheel and
pinion
40 0201 420
Complete barrel
with mainspring
39 0285 420
Ratchet wheel
38 0381 420
Click
37 0112 430 (Cal. 4205B, 4206B)
0112 432 (Cal. 4207B, 4208B, 4225A, 4227A)
Barrel and train wheel bridge
36 0396 420
Friction spring for second
wheel pinion
34 0012 485
Barrel and train wheel bridge
screw (B)
35 0012 484
Barrel and train wheel bridge
screw (A)
52 Center wheel with
cannon pinion
➡➡Please see the remarks on the following pages.
Cal. 4205B, 4206B, 4207B, 4208B, 4225A, 4227A

4
PARTS CATALOGUE
0012 484
0012 123
• Stud screw
Name
Part No.
•List of screws
0012 797
0012 488
• Oscillating weight with-
out pinion screw
Part No. Name
•List of jewels
Name
0011 333 • Upper hole jewel for third wheel
and pinion
0011 212 • Diashock upper cap jewel
• Diashock lower cap jewel
Part No.
0011 713 • Lower hole jewel for second wheel
and pinion
0011 541 • Upper hole jewel for fourth wheel
and pinion
Name
Part No.
• Center wheel bridge
screw
• Pallet cock screw
• Framework for automatic
device screw
• Date driving wheel screw
• Date dial guard screw
• Barrel and train wheel
bridge screw (B)
0012 485
0011 752 • Upper hole jewel for center wheel
and pinion
• Lower hole jewel for center wheel
and pinion
0011 528 • Upper hole jewel for escape wheel
and pinion
• Lower hole jewel for escape wheel
and pinion
0011 505 • Upper hole jewel for jewelled pallet
fork and staff
• Lower hole jewel for jewelled pallet
fork and staff
• Barrel and train wheel
bridge screw (A)
• Balance cock screw
• Setting lever spring screw
• Screw for locking seat for
idle wheel
• Day jumper screw
Cal. 4205B, 4206B, 4207B, 4208B, 4225A, 4227A
* Cal. 4205B has two more date dial guard screws
instead of the day jumper screw.
* Cal. 4207B also has the following parts
0011 333 Lower hole jewel for third wheel and pinion
0011 584 Lower hole jewel for fourth wheel and pinion
0011 751 Upper hole jewel for complete barrel with mainspring

5
•List of tubes
Part No. Name
PARTS CATALOGUE
0017 255 • Tube for center wheel bridge (B)
0017 259 • Tube for date dial guard (B)
0032 422 • Tube for pallet cock (B)
0032 421 • Tube for balance cock
0017 257 • Tube for date dial guard (A)
0032 420 • Tube for barrel and train wheel
bridge (A)
Part No. Name
0032 423 • Tube for locking seat for idle wheel
0032 424 • Tube for date driving wheel
0032 425 • Tube for barrel and train wheel
bridge (B)
0033 422 • Dial leg holder pin
0033 421 • Dial leg pin
* The type of holding ring for dial is determined based on the design of cases and dials. Check the
case number and refer to “SEIKO Watch Parts Catalogue CD-ROM” to choose a corresponding
holding ring for dial.
Remarks
3 Holding ring for dial
•Other parts
0341 432 • Regulator
Part No. Name
0014 414 • Diashock lower frame
0014 413 • Diashock upper frame
0014 417 • Diashock upper spring
• Diashock lower spring
Part No. Name
0014 415 • Diashock upper hole jewel with
frame
• Diashock lower hole jewel with
frame
0315 420 • Balance staff
0331 420 • Roller with jewel
0345 420 • Stud holder
5 Day star with dial disk
* If any type of day star with dial disk is required, specify the number printed on the disk.
12 Date dial
* The type of date dial is determined based on the design of cases. Check the case number and
refer to “SEIKO Watch Parts Catalogue CD-ROM” to choose a corresponding date dial.
Cal. 4205B, 4206B, 4207B, 4208B, 4225A, 4227A

6
PARTS CATALOGUE
16 Hour wheel
20 Cannon pinion
41 Second wheel pinion
52 Center wheel and pinion
Combination:
Type Cannon pinion Hour wheel
Second wheel
pinion
0271 427
0271 425
0225 427
0225 422
0245 427
0245 421
2
0224 421
0224 427
1
60 Winding stem 0351 420
* The type of winding stem is determined based on the design of cases. Check the case number
and refer to “SEIKO Watch Parts Catalogue CD-ROM” to choose a corresponding winding stem.
Center wheel and pinion
0271 426
0225 4230245 422 0224 422
3
Cal. 4205B, 4206B, 4207B, 4208B, 4225A, 4227A

7
TECHNICAL GUIDE
•The explanation here is only for the particular points of the calibres equipped with the day star with dial
disk and date dial.
11 Date dial guard
Set the protruding portion of the day-date corrector finger into the hole of the date dial guard (A
portion).
A portion of the date dial guard
Protruding portion of the day-date corrector finger
25 Pawl lever with jewel
If a tip of the pawl lever is on the top of the transmission wheel and pinion, insert something with a
sharpened tip through the hole of the framework for automatic device with ball bearing, and move
the tip of the pawl lever sideways so that the lever and the transmission wheel and pinion properly
engage each other.
Pawl lever with jewel
Hole of the framework for automatic device with ball
bearing
26 Transmission wheel and pinion
•Lubricating
45 Sliding crown wheel spring
When setting the sliding crown wheel spring, check that it engages the teeth of the sliding crown wheel.
Sliding crown wheel spring
Sliding crown wheel
(fixed to the locking seat for idle wheel)
Locking seat for idle wheel
Cal. 4205B, 4206B, 4207B, 4208B, 4225A, 4227A

8
47 Locking seat for idle wheel
•Lubricating
Sliding crown wheel
Locking seat for idle wheel
2005-05
TECHNICAL GUIDE
15 Day-date corrector finger
14 Date jumper
13 Date jumper spring
56 Setting lever
55 Yoke
•Setting position
Day-date corrector finger
Setting lever
Yoke
Date jumper spring
Date jumper
Cal. 4205B, 4206B, 4207B, 4208B, 4225A, 4227A