Seiko 5M42A, 5M43A Technical Manual

1

Movement size

The illustrations refer to Cal. 5M42A.

(x 1.0)

Movement

Item

[SPECIFICATIONS]

Cal. 5M42A
Cal. 5M43A

PARTS CATALOGUE / TECHNICAL GUIDE

4.3 mmHeight

Casing diameter ø27.0 mm

Capacitor voltage: 0.5 ~ 2.3V

From 1.55V to stoppage: Approx. 168 hours

Cal. No.

5M42A

5M43A

Outside diameter ø27.6 mm

3 hands

Time indication

Step motor (Load compensated driving pulse type)

Driving system

Monthly rate at normal temperature range: less than 15 seconds

Loss/gain

NilRegulation system

Use 10-second gate.

Measuring gate by quartz tester

Automatic generating systemPower generator

Polyacene lithium condenserCapacitor

Power supply

Operating voltage range

Duration of charge

6 jewelsJewels

• Automatic generating system

• Power reserve indicator

• Overcharge prevention function

• Electronic circuit reset switch

• Train wheel setting device

• Date calendar

• Day calendar (for Cal. 5M43A only)

• Instant setting device for date calendar

• Instant setting device for day calendar (for Cal. 5M43A only)

Additional mechanism

2

Disassembling procedures Figs. : 1 → 52
Reassembling procedures Figs. : 52 → 1

Lubricating: Types of oil Oil quantity

Moebius A Normal quantity
SEIKO Watch Oil S-6

Ex.: Cal. 5M43A

Cal. 5M42A, 5M43A

➡➡

Please see the remarks on the following pages.

PARTS CATALOGUE

0022 247

• Date dial guard screw (3 pcs.)

• Capacitor clamp screw (2 pcs.)

• Circuit block cover screw (2 pcs.)

• Oscillating weight bridge screw (2 pcs.)

• Coil block screw (1 pc.)

• Train wheel bridge screw (1 pc.)

0022 490

• Oscillating weight screw (1 pc.)

1 Hour, minute and second hands

15 0271 670

Hour wheel

Anti-magnetic shield plate
(The anti-magnetic shield plate is

welded to the main plate, and
they cannot be disassembled.)

14 0816 670

Date driving wheel

12 0962 670

Intermediate wheel for calendar correction

13 0810 660

Date jumper

11 0737 670

Day corrector setting wheel

10 Date dial

9 0808 660

Date dial guard

7 0989 660

Intermediate wheel for day correction
(Only for Cal. 5M43A)

8 0022 247

Date dial guard screw

6 Day star with dial disk

(Only for Cal. 5M43A)

5 0963 781

Snap for day star with dial disk
(Only for Cal. 5M43A)

4 0491 589

Dial washer

3 Holding ring for dial

2 Dial

3

PARTS CATALOGUE

Cal. 5M42A, 5M43A

➡➡

Please see the remarks on the following pages.

23 0022 247

Circuit block cover screw

33 4002 516

Coil block

32 0022 247

Coil block screw

31 4239 519

Generating stator

30 4146 518

Generating rotor

29 1002 660

Intermediate wheel for generating rotor

28 4002 519

Generating coil block

27 0198 660

Oscillating weight bridge

26 0022 247

Oscillating weight bridge screw

25 4000 731

Circuit block

24 4457 761

Circuit block cover

16 0022 490

Oscillating weight screw

17 0500 660

Oscillating weight

18 1002 662

Oscillating weight wheel

19 0022 247

Capacitor clamp screw

20 4225 518

Capacitor clamp

21 4216 509

Insulator for capacitor

22 3029 113

Capacitor unit

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



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



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







SET COD

E

R

echargeable battery

3023 5MZ

4

PARTS CATALOGUE

Cal. 5M42A, 5M43A

➡➡

Please see the remarks on the following pages.

52 0100 659 (One-piece case type)

0100 669 (Conventional case)
Main plate

50 Winding stem

51 0221 676

Center wheel and pinion

49 0282 672

Clutch wheel

48 4239 518

Rotor stator

47 0397 660

Lever for unlocking stem
(Only for one-piece case
type)

46 0383 662

Setting lever

45 0384 661

Yoke

44 4450 730

Switch lever

43 0281 670

Setting wheel

42 0261 670

Minute wheel

41 4146 531

Step rotor

40 0701 670

Fifth wheel and pinion

39 0231 530

Third wheel and pinion

38 0241 670

Fourth wheel and pinion

37 4271 515

Capacitor connection (+)

36 0391 660

Train wheel setting lever

35 0125 660

Train wheel bridge

34 0022 247

Train wheel bridge screw