Seiko S140A, S143A Parts Catalogue /technical Manual

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PARTS CATALOGUE / TECHNICAL GUIDE

Cal. S140A, S143A

Cal. No.

Item

S140A

(x 0.7)The illustrations refer to Cal. S143A.

Module

Module size

Outside diameter 49.3 mm between 6 o’clock and 12 o’clock sides

43.0 mm between 3 o’clock and 9 o’clock sides

[SPECIFICATIONS]

S143A

–Casing diameter

Height 8.75 mm

Display medium Nematic Liquid Crystal, FEM (Field Effect Mode)

Liquid crystal driving system

1/4 multiplex driving system

Display system • Stopwatch display (Up to 10 hours)

• Split time/lap time measurement

• Total time measurement/lap time measurement in progress

• Time/calendar display

• Stroke display (Only for Cal. S140A)

Additional mechanism • Memory function: Up to 300 measurements

• Memory capacity indicator

• Confirmation sound for watch operation

• Contrast adjustment function

• Battery life indicator

• Printout function (Only for Cal. S143A)

Regulation system

Nil

Measuring gate by quartz tester Any gate can be used.
Battery SEIKO CR2430, Sony CR2430

Battery life is approximately 3 years.
(When the stopwatch is used for 3 hours a day or less)
Voltage: 3.0 V

±0.0006% at normal temperature range (corresponds to a loss/gain
(monthly rate) of less than 15 seconds)

Loss/gain

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PARTS CATALOGUE

Cal. S140A, S143A

Disassembling procedures Figs. : 1 → 17
Reassembling procedures Figs. : 17 → 1

Lubricating: Types of oil Oil quantity

SEIKO Watch Oil S-6 Normal quantity
Silicone oil 500,000

➡

Please see the remarks on the following pages.
(Lubricating of some parts is shown in “III. REMARKS ON DISASSEMBLING AND REASSEMBLING”)

1 Case back screw

2 Case back

Piezoelectric element

3 Case back

gasket

4 Module

5 7504 620

Jack
(only for Cal. S143A)

Jack nut
(only for Cal. S143A)

Button B

Button C

Button A

Button D

Button spring clip

Button spring

7 0022 922

Circuit block
cover screw

6 Battery

(See the
front page.)

8 4457 753

(for Cal. S140A)
4457 754
(for Cal. S143A)
Circuit block
cover

9 4246 825

Buzzer lead
terminal

10 0353 503

Spring for
switch
conductivity

11 4410 779

Circuit block
case

12 4450 851

Switch lever

13 4000 875

(for Cal. S140A)
4000 872
(for Cal. S143A)
Circuit block

14 4313 825

Connector

15 Liquid crystal

panel

16 4313 826

Switch connector

17 4512 850

Liquid crystal
panel frame

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Remarks:

PARTS CATALOGUE

Cal. S140A, S143A

TECHNICAL GUIDE

• The explanation here is only for the particular points of Cal. S140A and S143A.

• For the repairing, checking and measuring procedures, refer to the “TECHNICAL GUIDE, GENERAL

INSTRUCTIONS”.

I. STRUCTURE OF THE CIRCUIT BLOCK

II. REMARKS ON BATTERY REPLACEMENT

Cal. S140A, S143A

15 Liquid crystal panel 4520 504

The type of liquid crystal panel is determined based on the design of cases. Check the case number and
refer to “SEIKO Casing Parts Catalogue” to choose a corresponding liquid crystal panel.

Cal. S140A Cal. S143A

C-MOS-LSI Input terminal (+)

Input terminal (–)Crystal unit

C-MOS-LSI Input terminal (+)

Input terminal (–)

Jack lead terminal

• Remarks on installing the battery

· Keep the battery level while installing it lest it should
touch the circuit block cover.

· Be careful not to short-circuit the battery connection (–)
and the circuit block cover. In that case, the display may
remain blank after the battery is installed.

* If the display remains blank, wait until the battery voltage

returns to the normal level. The normal display will
return.

Example of short circuit

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TECHNICAL GUIDE

Cal. S140A, S143A

• Remarks after installing the battery

After the battery is replaced with a new one, or after
the battery is re-installed following the repairing
procedures, be sure to short-circuit the AC terminal
of the circuit block and the circuit block cover with
conductive tweezers for more than 2 seconds as
illustrated at right to reset the circuit.

▼

III. REMARKS ON DISASSEMBLING AND REASSEMBLING

Use the universal movement holder for disassembling and reassembling.

4 Module (Only for Cal. S143A)

• How to remove

Unsolder them with a soldering iron, soak up the
melted solder completely with a solder wick or the
like, and then, remove the jack lead terminal.

• How to install

Set the jack lead terminal to the jack pin, taking care
not to set it upside down. Then, re-solder them with
the soldering iron.

The jack and the jack lead terminal are soldered together.

Note: When using the soldering iron, take utmost care not to deform or damage the case and other

parts by the heat of the soldering iron.

Case

Liquid crystal panel

Jack lead terminal

Soldered portion

5 Jack

The jack is only available for supply with the nut.

• How to install

To reassemble the jack, set the notch of the jack to the groove of the case.

9 Buzzer lead terminal

• How to remove

Remove the buzzer lead terminal after detaching the circuit block case from
the circuit block.

• How to install

To install the buzzer lead terminal, set the end portion of the buzzer lead
terminal to the groove of the circuit block case, and then, turn the buzzer lead
terminal slightly so that it does not come off.