witschi electronic basic course watches – measuring technology and troubleshooting start >>

Witschi Electronic

Basic course

Watches – Measuring technology and troubleshooting

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Introduction

Mechanical Watches

Quartz Watches

Water-resistance

Helpful and practical

Contents

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Introduction

About us

Witschi Electronic AG develops, manufactures and sells

Pioneering test and measurement technology for:

• Watch production

• Watch service

• Testing devices for automotive industry, medical industry and instrument manufacturing

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This basic course is intended to optimize our customers’ and the users’ knowledge of the Witschi devices and their

operating skills in this field.

Introduction

Aim of this course

..End..

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Contents

Introduction

Mechanical Watches

Quartz Watches

Water-resistance


Exit

Mechanical Watches HomeHome

Mechanical Watches

Main components of mechanical watches and their characteristics

Mainspring / barrel

Gear train / motion work

Regulating system

Escapement (escape wheel, pallet fork and impulse pin)

Automatic winding mechanism (only with automatic watches)

Winding shaft / crown

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Mechanical Watches

Measuring signals

Amplitude measurement

The amplitude of the balance wheel is determined from the velocity of the ellipse, passing through the lift angle of the escapement. (high velocity = large amplitude and vice versa). Typical values: watch horizontal: (approx.) 250-330° watch

vertical: (approx.) 240° at 0/h

+ 10s/d

Rate measurement The rate of the watch is based on a difference measurement between a highly accurate thermally stabilised quartz time base, e.g. in the Wicometre Professional and the actual rate of the watch.

Typical values: Normal watch (approx.) -5 - +20 s/d Chronometer (approx.) -2 - +6 s/d

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Mechanical Watches

Measuring signals

Beat error Millisecond variations of both beats ("tick" and "tock" of unequal duration).Typical values: 0.0 - 0.5 ms

+2.3 0.2 289

General graphical display

The general display generated by the Wicometre Professional is the result of all technical factors mentioned above during a certain time span. It indicates very accurately the technical state of the watch and it's faults, if any.

Splitting the escapement noise into its three main components gives a great deal of information about miscellaneous fault sources in the escapement and regulating parts (balance wheel / spiral system).

Beat noise

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Mechanical Watches

Functions of the Wicometre Professional

Rotary knob and buttons Display of results and parameters

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Mechanical Watches

The parameters of the Wicometre Professional

According to list(Witschi document)or individual

GRAPH – SCOPE 3

1 to 10 mm/ms

Individual 10 to 90°

Individual 2 to 240 s

MAN, SEL, FRQ

Individual settings

Automatic detection

Graph

2

52°

20 s

Aut (Automatic)

Universal setting

Selected beat number

Operating mode

Resolution / diagramm

Lift Angle

Measuring time in s

Beat number selection

Operation

Beats per Hour

Graph. Resol

Lift Angle

Meas Time

Parameter

Test Mode

Beat Mode

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Mechanical Watches


Mode Symbol Operation

Beat Mode

MAN

Manual selection: In this position, the parameter "BEATS PER HOUR" can be set to less frequently used beat numbers, which cannot be determined automatically, according to a list pre-programmed in the system.

SEL

Individual selection: In this position, the parameter "BEATS PER HOUR" can be set to any beat number from 1 to 36000 in steps of 1 by pressing or in steps of 100 by pressing both buttons.

FRQ

Determines the instantaneous frequency: This function allows testing of watches with an unknown beat number. The instantaneous beat number displayed corresponds to a rate = 0 s/24h.

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Mechanical Watches


Mode Symbol Funktion

Test Mode

GRAPH Normal operating mode with graphical diagram and display of numerical results.

PRIN XX

If a printer is connected to the WICOMETRE PROFESSIONAL, the numerical results for the rate, the beat error and the amplitude are printed at the end of the preset measuring time. The next measurement starts automatically at the completion of the freeze delay.

LAB -PC Similar to PRIN XX. However, the output results are passed to a PC through the serial interface RS 232 C.

SCOPE 1

Oscillogram representing a single beat noise (tick)

SCOPE 2

Oscillogram representing two beat noises ( tick-tock )

SCOPE 3

Oscillogram representing four beat noises (2x tick-tock)

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Mechanical Watches

Analysis and error detection with a graphical diagram

Amplification adjustment of the equipment:1 standard adjustment. If the diagram appereance is disturbed, the signal amplification can be reduced or increased by means of the rotating knob.

1

Watch movement in good condition.Rate : +1 up to +15 s/dAmplitude: H.: approx. 250 - 330° V.: 220 - 270° Beat error: ca. 0.0 up to 0.5 ms.

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Mechanical Watches

Analysis and error detection with a graphical diagram

Watch movement in good condition.Beat error: too large (approx. 3 mm/ms)Correction: adjust beat error only and readjust the rate.

A + 90 s/d B - 90 s/dWatch movement in good condition.Movement A: large gainMovement B: large lossCorrection: readjustment of the rate, approx. +2 up to +15 s/d

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Mechanical Watches

Analysis and error detection with a graphical chart

Movement A Pos CU Movement A Pos. CD

+ 40 s/d - 90 s/d

Watch movement with large rate variations between the various vertical positions.Correction: center, poise balance or exchange the complete regulation system.

Movement A Pos HU Movement A Pos. CD

+ 10 s/d - 10 s/d

Watch movement with small rate variations between the horizontal and vertical positions (isochronism).Correction: Check distance between the curb pins: vertical – (loss): reduce distancevertical + (gain): increase distance

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Mechanical Watches


Watch movement with irregular rate and defects. Usually the amplitude is insufficient.Correction: overhaul.

Watch movement with large, but regular rate variations: = technical defect in the gear train.Correction: overhaul + possible exchange of some gear-train parts.

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Mechanical Watches


Balance wheel "knocks" with interruptions (occasionally). Usually too high amplitude (+330°) + double "tick-tock" in loud speaker.Correction: exchange mainspring, pallet fork and/or escape wheel.

Balance wheel "knocks" continuously. Usually the amplitude is too high (+330°) + double- "tick-tock" in loud speaker.Correction: exchange the mainspring, pallet fork and/or escape wheel.

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Mechanical Watches


Entry pallet of the pallet fork does not lock correctly, or is dirty.Correction: clean the pallet fork and escape wheel, or exchange the pallet fork.

Excentric escape wheel.Correction: exchange the escape wheel.15 – 21 teeth = 1 turn of the escape wheel

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Mechanical Watches


Balance spring touches. In this case usually the balance spring touches the curb pins or the stud. (Scratching noises in loud speaker).Correction: center balance spring / adjust

Slow recovery of the balance wheel amplitude after changing position. Bearings for balance wheel and gear train are badly or not lubricated. Correction: clean and lubricate, possibly overhaul.

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Mechanical Watches


0.0 to 0.5 ms220 to 270°250 to 330°-5 to + 15 s/dChrono-graph

0.0 to 0.5 ms220 to 270°250 to 330°-2 to + 6 s/dChrono-meter

0.0 to 0.5 ms220 to 270°250 to 330°-5 to + 25 s/dLady's watch

0.0 to 0.5 ms220 to 270°250 to 330°-5 to + 15 s/dGent's watch

Beat errorAmplitude V.*Amplitude H.*Rate in s/dWatchtype

* Amplitude values when movement is fully wound. (Amplitude values after 24 h: decrease of approx. -10% to -15% is o.k.)

Good standard values

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Mechanical Watches

Analysis and error detection, using the graphical scope function

Between noises A and C, the balance wheel rotates by what is called the lift angle

Image of the beat - normal

pallet operation

the impulse pin touchesthe pallet fork

the entry pallet freeing itself from the escape

wheel

the escape wheel is dropping

on to the exit pallet

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Mechanical Watches


Escapement locking too small Escapement locking too large

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Mechanical Watches

Analysis and error detection, the graphical scope function

Unlocking resistance too high Additional friction

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Mechanical Watches


Dart touching the roller Not enough clearance between the horns and the impulse pin

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Mechanical Watches


Low amplitude Too much clearance between balance pivot and jewel hole

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Mechanical Watches


Impulse pin touching the fork horn

Rough balance pivot or insufficient clearance

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Mechanical Watches


Balance wheel touching balance spring

..End..

A tooth of the escape wheel drops directly on to the impulse plane (No locking function)

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Contents

Introduction

Mechanical Watches

Quartz Watches

Water-resistance


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Quartz Watches Home

Gear train and motion work

Stepping motor

Quartz resonator

Quartz Watches

Main components of autoquartz and quartz watchesand their characteristics

Battery

Integrated Circuit ( IC )

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Quartz Watches

Measuring signals

All rate measurements with quartz watches are based on the acquisition of the following signals:

Back

Analogue or analogue/digitalquartz watches

Quartz frequencyAcoustic or capacitive

Stepping motorInductive(magnetic)

Digital – quartz watches

Quartz frequencyAcoustic Working frequencyof the digital display:Capacitive on the watch glassFrequency: 4, 8, 16, 32 or 64 Hz.

Sat06.01.0310:34:42

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Quartz Watches

Measuring signals

Quartz oscillator

The measurement of the quartz frequency (nominal: 32'768 Hz) occurs over the acoustic or the capacitive (by opened watches) sensor. For the rate adjustment 2 different methods are usually used:

IC / Oscillator

Quartz

Trim.

A: Adjusted quartz oscillator frequency. Adjustment with a trimmer (out dated) or fixed capacitor "fix cap".The true rate can either be obtained via acoustical / capacitive measurements of the quartz frequency or magnetically via the motor pulses.

IC /mitEEPROM

Quartz

B: The quartz oscillator frequency is not adjustable. The programmable IC is digitally adjusted (inhibition).A programmable number of oscillator pulses is inhibited once per minute (for some IC's every 20s, 30s or every 2, 4 and 8 minutes) during frequency division, i.e. they are not transferred to the next divider stage. By using this method the quartz oscillator runs fast, approx. +3-5 s/d. The true rate can only be measured via the motor pulse with a measuring time of => 60 s

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Quartz Watches

Measuring signals

Motor pulse

The motor pulses (pulse period 1s, 5s, 10s, 20s, 30s or 1 min.) are picked up inductively over the magnetic sensor.The stepping motor is driven from the IC’s driver stage with pulses like:

Back

A: fixed pulses with constant or variable pulse width.

IC Motor

or for new systems

B: chopped pulses with constant pulse width, but chopped pulses which are continuously adapted to the watch movement’s condition for a lower current consumption.

IC Motor

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Quartz Watches

Functions of the Q Test 6000

Displays Signal sensors

Connections and buttons

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Quartz Watches

Operating the Q Test 6000

Tests with built in, functioning battery

3 4

1

2

Short test of the quartz and IC operation

(test of the quartz signal)

1 Place the watch on the "acoustic " microphone

2 POS: Testmode Rate: Quartz 32 KHz Test ok if:

3 Signal "quartz" lights up in display "RATE".

4 Rate (quartz frequency) of the watchon Display RATE :approx. 0.00 to approx. + 6 s/d = ok

Quartz + IC Test

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Quartz Watches



Test of the magnetic motor pulse

1 Place the watch on the "magnetic/capacitive" microphone

2 POS: Testmode Rate : stepp. motor Test ok if:

3 Signal "motor" in display "RATE" lights up (pulse)

1

3

2

Motor Test

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Quartz Watches



Rate measurement

Back

Test of the rate accuracy

1 Place the watch on the "magnetic / capacitive" microphone

2 POS: Testmode Rate: stepp. motor

3 POS: Set the parameter meas. time on 60 s with the rotary knob.

4 POS: Press Start test:

5 Result after 60 s in RATEnormal values: (approx.) -0.05 to + 0.35 s/d or -2 to + 15 s/m

1

2

34

5 3

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Quartz Watches


Tests with external supply / without battery

1 POS: Testmode Module: Battery test

2 Test currents

Nominal: 2A = current consumption

Low Drain: 750 A = peak Motor High Drain: 15 mA = peak Backlight

1

2

Battery tests

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Quartz Watches



Minimal values

System V min. nominal

V min. low drain

V min. high drain

Silveroxide low drain 1.55 1.45 ----

Silveroxide high drain 1.55 1.45 1.25

Lithium low drain 3.00 2.85 ----

Lithium high drain 3.00 2.85 2.60

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Coil insulation: B1 POS: Testmode Module: resistance2 1st test probe to a coil connection 2nd test probe to the plate Normal values: approx. 700 kOhm to X MOhm

Movement insulation: C1 POS: Testmode Module: resistance2 1st test probe to - pole of the battery 2nd test probe to the plate Normal values: approx. 700 kOhm - X MOhm

Coil resistance: A1 POS: Testmode Module: resistance2 Test probes to coil connections Normal values: approx. 1 to 3 kOhm

1

2

A

Coil resistance / Insulation test

CB

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Quartz Watches



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Quartz Watches



4 POS: Testmode Module: consumption µA

5 connect minus test probe with RT/T test point on movement’s module.

6 Reduce current voltage with rotary knob until gear train stops.

1 Place the watch on the mirror table and

connect both

2 battery connectors to Module Supply by means of the movable contact picks.

3 POS: Parameter: Supply voltage - Set start at 1.55 or 3.00 Volt with the rotary knob

12

34

5

6

<= 1.15 V2 dial trains

<= 1.3 V3 dial trains

Normal values

Starting voltage

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Quartz Watches



Rate and consumption measurement

Back

1 Place the watch on the mirror table

2 Connect battery connectors to Module Supply. Set the following parameters with the rotary knob:

3 POS: Parameter: Supply voltage - Voltage on 1.55 or 3.00 volts

4 POS: Parameter: meas. time rateSet measuring time to 60 s

12

34

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Quartz Watches



Rate and consumption measurement

Back

5 POS: Parameter meas. time cons. Set measuring time to 60 s

6 POS: Testmode Module: on consumption µA

7 Start test: Measurement countdown can be observed on: POS countdown meas. time and countdown cons can be observed Result shown on displays: Rate (Rate) and Module (cons.)

6

7 5

12

34

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Quartz Watches



Pulse generator

The simulation of the watch’s IC by the pulse generator is carried out with a non-chopped pulse of variable length.

Back

3.9ms 5.8ms 7.8 ms

The watch’s IC is replaced by the pulse generator Q Test 6000.

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Quartz Watches



12

3 4

5


2 Connect the coil connections on the Module Supply. Set the following parameters with the rotary knob:

3 POS: Testmode module: Puls generator

4 POS: Testmode Module: Supply voltage Voltage at 1.35 or 2.80 volts in display Parameter)

5 POS: Parameter: Pulse width Start with pulse length 2.9 ms and increase pulse length until the watch runs.

5.8 – 6.8 ms4.8 – 5.8 ms3.9 - 4.8ms

adequategoodvery good

Normal motor pulse length values

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Pulse generator

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Quartz Watches


IC programming and accelerated rate test ( real rate )

12

3

4

5


2 Connect battery connectors to Module Supply. Set the following parameters with the rotary knob:

3 POS: Parameter: Supply voltage - Voltage on 1.55 Volt

4 POS: Parameter: special program - Setting P1 - P4 according to IC Typ

5 POS: Testmode Rate: quartz 32 kHz

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Settings

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Quartz Watches



Tests

12

3

4

5

6

6 Accelerated rate test POS: Test control: start test - Press briefly. The real rate of the watch is briefly shown.

IC programming POS: Test control: simultaneously press keys start test and print result for 2-3 sec. The IC is reprogrammed.

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Quartz Watches



Special Programm / programmed IC types

P1 Philips Series PCA 1400P2 Philips Series 1460 / 1480 / 1600P3 MEM H1138/ H1140/ H1238/ H1338/ H1538P4 MEM H1221/ H5222SPL

Note

Rate: Must appear in display RATE after accelerated test and after programming. If not: select another programming program (P1-P4).

Back

IC Typen

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Quartz Watches


Systematic troubleshooting

Back

Tests and settings Test sequence

Battery not ok Battery ok

Remove and test the battery

Battery testPOS: Testmode module: battery testCaution:Always check the movement for corrosion and the insulation of the battery case!

Situation: watch stopped

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Quartz Watches



Battery not ok Battery ok

Remove and test the batteryBattery testPOS: Testmode module: battery testCaution: Always check the movement for corrosion and the insulation of the battery case!

Situation: watch stopped

Values ok

Test of the coil resistance and of the insulation values:

POS: Testmode Module: resistance

Test of the coil resistancecoil and movement

insulation, without external power supply and without

battery

Values not ok

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Tests and settings Test sequence

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Quartz Watches



Test of the coil resistance and of the insulation values:

POS: Testmode Module: resistance

Replace the electronic module

Values not ok

Values ok

Test of the quartz and IC operation:POS: Testmode Rate: stepp. MotorPOS: Testmode module: cons. APOS: Parameter: supply voltage 1.55V - 3.00 V - Winding stem - POS: Reset

Test of quartz and IC- place watch on the mirror support, connect external

power supply module supply to the

battery connectors

Values not ok

Values ok

Test of the coil resistancecoil and movement

insulation, without external power supply and without

battery

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Quartz Watches



Values ok

Test of the quartz and IC operation:POS: Testmode Rate: stepp. MotorPOS: Testmode module: cons. APOS: Parameter: supply voltage 1.55V - 3.00 V - Winding stem - POS: Reset

Test of quartz and IC- place watch on the

mirror support, connect external power supply module supply to thebattery connectors

Values not ok

Test of the stepping motor:- Winding stem - POS: NeutralPOS: Testmode Rate: stepp. MotorPOS: Testmode module: cons. APOS: Parameter: supply voltage 1.55V - 3.00 V meas.time rate 60 s meas.time cons. 4 sPOS: test control: start test

Test of the stepping motor- place watch on the mirrorsupport, connect external

power supply module supply to the battery

connectors

Back

Replace the electronic module

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Quartz Watches



Test of the stepping motor:- Winding stem - POS: NeutralPOS: Testmode Rate: stepp. MotorPOS: Testmode module: cons. APOS: Parameter: supply voltage 1.55V - 3.00 V meas.time rate 60 s meas.time cons. 4 sPOS: test control: start test

Test of the stepping motor- place watch on the mirrorsupport, connect external

power supply module supply to the battery connectors

Test of the starting voltage- Same test as stepping motor;- battery test tip with RT/T measuring point of the movementStart with:POS: supply voltage 1.55-3.00VVoltage reduced until the movement stops

Test of the lower starting voltage

- place watch on the mirror support,connect external power supply module supply to the battery

connectors,and the negative test probe with

RT/T

Values ok-new battery-close watch

Values not ok

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Quartz Watches



Important mechanical tests:

- steel particles block the rotor/gear train - particles between crown and case block the reset

mechanism- hands touch the inside face of the glass- hands have no axial freedom- Calendar mechanism

Mechanical test

Test of the starting voltage- Same test as stepping motor;- battery test tip with RT/T measuring point of the movementStart with:POS: supply voltage 1.55-3.00VVoltage reduced until the movement stops Values ok

-new battery-close watch

Test of the lower starting voltage- place watch on the mirror support,

connect external power supplymodule supply to the battery connectors- minus battery test tips to the test point

RT/T of the movement

Values not ok

Back

..End..

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Contents

Introduction

Mechanical Watches

Quartz Watches

Water-resistance


Exit

Water-Resistance Home

Water-resistance

Water-resistance standard ISO 2281

Basic standards for ordinary watchesThe basic standards for all definitions, test methods, min. / max. values, tolerances, etc. are contained in the three standards ISO 2281 / DIN 8310 and NIHS 92 - 10.The test procedures described in DIN 8310 and NIHS 92 - 10 are, to a large extent, similar, national versions of the international standard ISO 2281

The label "water-resistant".The label of wristwatches which meets the minimal requirements of this standard must only contain a single expression in each language:In german: wasserdicht / in french : étanche / in english : waterresistant

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Water-resistance

Water-resistance standard ISO 2281

Practical aspects of the label "water-resistant".Watches which are designated as water-resistant must be resistant to sweat, water drops, rain, etc. and to immersion into water:

- at a depth of 10 cm (excess pressure of 0.01 bar) for 1 hour and … - at a depth of 20 meter (excess pressure of 2.0 bar) for 1 min.

Minimal requirements ( standard converted to air pressure measurements )A watch fulfils these requirements if:

- the air penetration into the watch- under an excess air pressure of 2 bar- for a 1 minute test- does not exceed 50 g ( microgram )

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Water-Resistance

Test methods

Volume comparison measurement

Measurement principle:

The following values are determined by performing a calibration cycle:Measurement 1: Entire volume of the test chambers without watchesMeasurement 2: - Volume of the watchesResult: = Remaining free space in the chambers

During the work cycle, the ALC 7000 monitors the variation in the calibrated remaining free space and determines on this basis whether the watches are water-resistant or not.

Field of application: Ideal for industrial applications and series production

( unsuitable for service applications )

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Water-Resistance

Test methods

Deformation measurement


A given pressure or vacuum is created in a measuring chamber.

The external geometry of the watch undergoes a deformation due to the elasticity of the case materials.

The sensory part of the system then tracks the reversal of the deformation of the watchcase’s parts during the whole measurement process and, based on it, determines if the watch does or does not correspond to the given tolerances for water-resistance.

Field of applications: Industry: small and medium series Services: Repair shop and und retail business

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Water-Resistance

Test methods

Condensation test

Back


The watch, first tested under pressure underwater, is then brought to a temperature of 40 to 45 degree on a heating plate for approx. 30 min. One then pours a drop of warm water ( 18 - 25 degree ) onto the watch-glass.Water condenses on the inside face of the glass if the watch is not water-resistant.

Field of applications: Manufacturing and laboratory

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Water-Resistance

Test methods


Back

Pressure build-up Measuring time

Reversal deformation (- value)Accebtable measuring results:Lady‘s watch max. -2.5% watch ok Gent‘s watch (Norm) =/< 1% watch ok

0- Deformation: i.e. very hard material. watch ok

Further + deformation during test cycle:= high elasticity of materials. Measuring result: + 0,1%- + x% - watch ok.

Stab.time

Pressure process ALC 2000

Deformation of the watch

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Water-Resistance

Test methods


Back

Stab.time Vacuum build-upMeasuring time

Deformation of the watch

Vacuum process ALC 2000

Reversal deformation (- value)Accebtable measuring results:Lady‘s watch max. -2.5% watch ok Gent‘s watch (Norm) =/< 1% watch ok

0- Deformation: i.e. very hard material. watch ok

Further + deformation during test cycle:= high elasticity of materials. Measuring result: + 0,1%- + x % - watch ok.

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Water-Resistance

Operating the ALC 2000

Witschi ALC 2000 parameters / operations / valuesISO parameters

Test of water resistance under vacuum:The partial vacuum test is primarily designed fordetecting small leaks and faulty assembly of caseparts. The negative test pressure corresponds to thenormal strain on the watch (showering, swimming, etc.). ALC 2000 parameter : from - 0.2 to - 0.8 bar

Measurement under vacuum

No ISO standard

Back

Test of water resistance under pressure:( Test of the design of the watchcase’s parts )according to data from the watch manufacturer.ALC 2000 parameter : from + 0.2 to +10 bar

Positive pressure measurement

ISO standard:2 bar

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Water-Resistance



The sealing limit of 50 micrograms of air penetration per minute given by the ISO standard approximately corresponds to a 1% reversal of the case deformation.

The ISO standard does not take into account the size of the case.

ALC 2000 parameter for the “tight” limit:

Case 20-35 mm: 1% (default value)

Case > 35 mm: 0.5% (pocket-watches)

Case < 20 mm: 2 - 2.5% (lady’s watches)

Sealing (tight) limit

- ISO standard:

50 micrograms of air penetration per minute. Without

taking into account the size of the watch case

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Water-Resistance



ALC 2000 parameter / Measuring times:variable from 10 to 300 sec. + automatic measuring time.Witschi recommends using the variables"Auto Measuring time". Optimisation of themeasuring time in dependence on the deformation

Measuring time

- ISO standard : 1 min.

The deformation factor can vary much according tothe case material and geometry (e.g. carbideor curved case). This is why the ALC 2000provides 2 sensor setting :Standard: for all "normal" cases with flat glass.Hard: for all carbide and curved cases.

Case material and watch shape taken

into account

- No ISO standard

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Water-Resistance


Witschi’s ALC 2000 has been designed to be a highly accurate, professional test system.

The adjustable parameters have been given a great flexibility, allowing checking practically all makes of watches with the utmost reliability.

The parameterization offered by Witschi’s ALC 2000 is significantly more specific and tailored to the type of watch than the minimal requirements from the ISO 2281 standard.

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Water-Resistance


back to the main menu or to the standard measurement program PO

parameter selection

entering the desired values + and -

Test 2 good (green), bad (red) or undetermined (yellow)

Test 1 good (green), bad (red) or undetermined (yellow)

becomes yellow when the watch is correctly placed on the sensor

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Water-Resistance


Basic settings

Enter in Program:Keep the button

pressedIn and switch the unit on

by means of the I / 0 switch. Wait until the

displayChange language

appears. Entering client label A – Z / a-z Next character

with with escape

Language:Select the languagewith the arrow keys with with escape

Display of the numerical results: yes / no

with with escape

Back

Compressor Type : with / without reservoir with with escape

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Water-Resistance


Measurement program

Selection of existing measuring programs 0 = fix / 1 - 10 variable

P1 Save parameters ?

P1 Parameters saved

P1 Case analysis

Push

Push

Push

Push

P1 Tight limit

P1 Measuring time

Switch on unit : I / 0

Editing new program ( 1- 10 )

Push

P1 Test with (1/2) pressures

P1 Lower pressure

P1 Higher pressure

Push

Push

Push

Push

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Water-Resistance

Main reasons for a faulty water-resistance

Advantages of the test with excess pressure and partial vacuum

• Faulty water-resistance due to inaccurate assembly and a to weak press-fit of components. (seat of the glass and back gasket). Such cases of faulty water- resistance can only be detected with low test pressure, especially with partial vacuum. The stress on the parts is very different according to whether the test is performed under positive pressure or partial vacuum.

• Faulty water resistance due to parts of the case and gaskets being deformed in the course of an excess pressure test. This faulty water-resistance only appears in excess pressure tests.

• Faulty water-resistance due to bad manufacturing (out of truth in the round or in the flat) of the case and of other components.

There can be 3 main reasons for a faulty water-resistance:

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Water-Resistance



Main reasons / faulty water-resistance - defect, old and dirty seals (crown / back / glass) - porous and old glasses with fissures (Acryl) - defective crowns- wrong glasses

In a test with excess pressure, the parts are held or even squeezed together by the pressure.

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Water-Resistance



In a test with partial vacuum, the components are only held together by their own friction and by their correct dimensions (snug fit)

Back

..End..

Main reasons / faulty water-resistance - wrong seals, e.g. too thin (crown / back / glass) - poorly assembled glasses or seals for crowns bottoms and battery containers -tube for crown not round

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Contents

Introduction

Mechanical Watches

Quartz Watches

Water-resistance


Exit

Witschi measuring tips Home

Witschi measuring tips

Mechanical Watches

Before measuring on-Watch Expert-Wicometre Professional-Chronoscope M1

Explanation Procedure Measuring sequence

Same as for dateCrown in "0" (inside) position

The rate of the watch becomes stabile and the test system displays a regular diagram

Wind the watch (turn the crown 10 to 15 times) and let it run from5 to10 minutes

The date change can cause a bias the current rate.

The hands should not be inthe position just beforemidnight ( i.e. datechanging )

Mechanical watches are generally antimagnetic, yet check it out.Magnetised watches display a diagram similar to that of a very dirty movement.

Demagnetise the watch(if possible) with a demagnetising device.

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Mechanical Watches

Measuring procedurewoundwatch

Shortcut; the stabilisation time between the individual vertical positions is shorter, than between horizontal and vertical positions.

Start the rate measurement ina vertical position Crown pos. 6h, 9h, 12h, possibly 3hand then horizontalDial up and dial down.

The measuring results for each position become more precise and regular. For normal measuring values see chapter:"Analysis and error detection with the diagram".

Allow a stabilisation time of approx.10-15 sec. between eachsingle position beforestarting measurement(approx. 10 to 20 sec.per pos.)

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Explanation ProcedureMeasuring sequence

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Mechanical Watches

Check the correct function of the watch.

After measuring

Check the date change andthe power reserve ofthe watch

Check the winding mechanismof automatic watches with a simulator

Check the watch for 24 hours.

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Quartz Watches

Visually inspect the watch for cleanliness, especially therotor and themechanical parts.

Removing any foreign bodiesand particles sometimes solves

the problem very quickly.

Check the battery voltageunder load(Nominal, Low Drain,possibly High Drain).

The battery can still show good values with an ordinary multimeter (without load resistance), although it indicates almost deadif measured with a load.

Clean the battery contacts,Particularly the minus (-) pole under the battery.

Dirty/oxidized contacts alter if not hinder measurements, even if the best testing device is being used.

Test the position of the watch crown. Pos. must be 0 (inside)

When the hand setting stem of almost any quartz Watches is pulled, the power saving function “reset“, i.e. motor pulses,is on.

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Before measuring

on: - NT Handy - Q Test 6000 - Analyzer Q2


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Suggestions for measuring

Quartz Watches

Measuring procedure

Start the rate measurement afterchecking both the battery withthe acoustic microphone andthe function of the quartz/IC.

The battery, as well as the Quartz/IC unit, drive the stepping motor.

Getting no signal means that the quartz or IC is faulty!

A) Analogue quartz watchesPlace the watch on themagnetic sensor(inductive) and check that motor pulses are present.

No pulse means a faulty coil.

If pulses are ok but the hands do not move, check the motor, the gear train and the motion work.

B) Digital quartz watches-Place the digital watch with the display downwards on the capacitive sensor(pos. LCD). Then check the rate.

No signal and nothing on the display: replace the

module

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Quartz Watches

After measuring

Check the date change in the watch. Test for more than 24 hours

Test of the mechanicaldate function.

24 25

Test the function of the hands.(they could touch the glass).

Check the hands function in“dial down“ pos. Test for more than 1 hour.

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Water-Resistance

Before measuring

Test the material of the watch caseand glass for visible damageand dirt on the case and glass.

Watches with a faulty (cracked) glass should not be tested. The watch to be measured must be clean.

Pay particular care and attention to position screwed-in crowns.

Crown position: 0

(internal position) or screwed in.

Fluctuation of the temperature during the measurement may falsify the measuring results.

Do not keep the watch in your hand

too long. When being tested, thewatch must have the same ambient temperature as the device.

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Water-Resistance

Remove any synthetic dust-proofadhesive from case backand/or from the glass

Foils alter the results due to the air trapped inside

Before measuring

When testing, follow the suggestions of the manufacturer.

2bar-3bar-5bar-10bar 20-xbar.

Notice the informationconcerning water-resistance(test pressure) from themanufacturer.

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Water-Resistance

Measuring time is optimised When possible use the automatic measuring time

Choose a programme suitable for the watch (see list by Witschi).

Measuring procedure

Placing the watch on the measuring sensor:A) watches with a flat glass: dial upwardsB) watches with a strongly curved glass: (cambered case) dial downwards.

If possible test the watch through:

A) depression (vacuum)andB) an pressure

Measurements based on negativepressure = very fast location of small leakages (gaskets, etc.) Measurements based on excess pressure indicate the state of the case.

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Water-Resistance

After measuring

Repeating the

measure-ments in

case of bad results

If a measurement gives a negative result (not ok) it is advisable not to immediately perform immediately a second measurement of the watch.

Advice: pull the crown into the external position and, after 10 to 20 seconds, return it to the internal position.

NOTOK

Quality assurance Print the measuring protocol.

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..End..


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Contents

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Introduction

Mechanical Watches

Quartz Watches

Water-resistance


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