Seiko YT57B Quick start guide

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[SPECIFICATIONS]
Cal. No.
Item YT57B
Movement
(x 1.0)
Additional mechanism • Automatic generating system
• Energy depletion forewarning function
• Overcharge prevention function
• Electronic circuit reset switch
• Train wheel setting device
• Date calendar
• Instant setting device for date calendar
Driving system Step motor (Load compensated driving pulse type)
Loss/gain Monthly rate at normal temperature range: less than 20 seconds
Regulation system Nil
Measuring gate by quartz tester Use 10-second gate.
Power
supply Automatic generating systemPower generator
PARTS CATALOGUE /TECHNICAL GUIDE
Cal. YT57B
Movement
size Outside diameter ø27.6 mm
Casing diameter ø27.0 mm
Height 4.3 mm
Time indication 3 hands
Operating voltage range 0.45 V ~ 2.2 V
Duration of charge From full charge to stoppage: Approx. 6 months
Jewels 6 jewels
KINETIC E.S.U. Titanium lithium ion rechargeable battery

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PARTS CATALOGUE
Disassembling procedures Figs. : 1 →47
Reassembling procedures Figs. : 47 →1
Lubricating: Types of oil Oil quantity
Moebius A Normal quantity
Moebius F
SEIKO Watch Oil S-6
➡Please see the remarks on the following pages.
Lubricating of some parts is shown in “II. REMARKS ON DISASSEMBLING AND REASSEMBLING”.
Cal. YT57B
0022 247
• Date dial guard screw (3 pcs.)
• Rechargeable battery 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
4 0022 247
Date dial guard screw
5 0808 660
Date dial guard
8 0962 670
Intermediate wheel for
calendar correction
7 0737 670
Date corrector setting
wheel
9 0810 660
Date jumper
10 0816 670
Date driving wheel
11 0271 670
Hour wheel
6 Date dial
2 Dial
3 Holding ring for dial

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PARTS CATALOGUE Cal. YT57B
➡Please see the remarks on the following pages.
Lubricating of some parts is shown in “II. REMARKS ON DISASSEMBLING AND REASSEMBLING”.
12 0022 490
Oscillating weight screw
13 0500 661
Oscillating weight
16 4225 519
Rechargeable battery clamp
15 0022 247
Rechargeable battery clamp screw
17 4216 519
Insulator for rechargeable battery
18 3023 24T
Rechargeable battery unit
19 0022 247
Circuit block cover screw
20 4457 760
Circuit block cover
21 4000 734
Circuit block
14 1002 662
Oscillating weight wheel
22 0022 247
Oscillating weight bridge screw
23 4459 500
Conductive plate
24 0198 662
Oscillating weight bridge
25 4002 514
Generating coil block
26 1002 660
Intermediate wheel for generating rotor
27 4146 518
Generating rotor
28 4239 519
Generating stator
30 4002 516
Coil block
29 0022 247
Coil block screw

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PARTS CATALOGUE Cal. YT57B
➡Please see the remarks on the following pages.
Lubricating of some parts is shown in “II. REMARKS ON DISASSEMBLING AND REASSEMBLING”.
44 Winding stem
45 0282 672
Clutch wheel
46 0221 676
Center wheel and pinion
47 0100 669
Main plate
43 4239 518
Rotor stator
31 0022 247
Train wheel bridge screw
32 0125 661
Train wheel bridge
33 0391 660
Train wheel setting lever
34 4271 515
Rechargeable battery
connection (+)
35 0241 670
Fourth wheel and pinion
36 0231 530
Third wheel and pinion
37 0701 670
Fifth wheel and pinion
38 4146 531
Step rotor
39 0261 670
Minute wheel
40 0281 670
Setting wheel
41 0384 661
Yoke
42 0383 662
Setting lever

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PARTS CATALOGUE Cal. YT57B
Remarks:
3 Holding ring for dial 0866 636
The type of holding ring for dial is determined based on the design of cases.
Check the case number and refer to “SEIKO Casing Parts Catalogue” to choose a corresponding holding
ring for dial.
Color of
background
White
Black
3 o’clock
3 o’clock
Position of
crown
3 o’clock
3 o’clock
Position of
calendar frame Color of figure
Black
White
Part code
0878 729
0878 730
6 Date dial
The type of date dial is determined based on the design of cases.
Check the case number and refer to “SEIKO Casing Parts Catalogue” to choose a corresponding date
dial.
44 Winding stem 0351 653
The type of winding stem is determined based on the design of cases.
Check the case number and refer to “SEIKO Casing Parts Catalogue” to choose a corresponding
winding stem.
TECHNICAL GUIDE Cal. YT57B
•The explanation here is only for the particular points of Cal. YT57B.
•For the repairing, checking and measuring procedures, refer to the “TECHNICAL GUIDE, GENERAL
INSTRUCTIONS”.
I. STRUCTURE OF THE CIRCUIT BLOCK
Coil output terminal
Crystal unit
Input terminal (–) C-MOS-IC
Input terminal (+)
Automatic generating input terminal

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TECHNICAL GUIDE Cal. YT57B
Place the movement directly on the riveting plate shown in the illustration with the oscillating weight
down, so that the oscillating weight screw is not damaged. Then, press in the hands.
12 Oscillating weight screw
Tighten the oscillating weight screw firmly,
applying more force than usual.
Oscillating weight screw
II. REMARKS ON DISASSEMBLING AND REASSEMBLING
For disassembling and reassembling, be sure to use the universal movement holder.
1 Hands
18 Rechargeable battery unit
Though they have a close resemblance in shape, the rechargeable battery unit for Cal. YT57B is of a
completely different type from that for Cal. 5M6 Series. They can be discriminated in the point that the
latter has a hole for discrimination on its minus lead terminal while the former doesn’t as illustrated
below. When repairing the rechargeable battery unit, check that it has no hole for discrimination on the
minus lead terminal to make sure you are using the proper one.
Minus lead terminal
[ Rechargeable battery unit for Cal. YT57B ] [ Rechargeable battery unit for Cal. 5M6 Series ]
Minus lead terminal
No hole for
discrimination Hole for
discrimination

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TECHNICAL GUIDE Cal. YT57B
•How to remove
Insert the tip of tweezers into the “C” portion
gap in the illustration at right, and pry up the
rechargeable battery unit to remove it.
•How to install
Set the “A” portion of the minus lead terminal
to the hole of the main plate, and push the “B”
portion down vertically so that the
rechargeable battery unit is well seated in
position.
Note: Take utmost care not to short-circuit the
(+)and(–)terminals,asthiswilldeteriorate
the battery unit.
“A” portion
Main plate
“C” portion Minus lead terminal
Rechargeable
battery plus
terminal
“B” portion
20 Circuit block cover
Circuit block cover for after-sales servicing use
hasno suchmarks printedon itas calibrenumber
and numeral indicating hand installation height.
21 Circuit block
The circuit block for Cal. YT57B and that for Cal. 5M6 Series have a close resemblance in shape. They
can be discriminated in the point that the former has a hole for discrimination while the latter doesn’t
as illustrated below. When repairing the circuit block, check the hole for discrimination to make sure
you are using the proper one.
Hole for discrimination No hole for discrimination
[ Circuit block for Cal. YT57B ] [ Circuit block for Cal. 5M6 Series ]

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TECHNICAL GUIDE Cal. YT57B
Lubricating: : Moebius A
22 Oscillating weight bridge screw
24 Oscillating weight bridge
· Before tightening the oscillating weight bridge
screw, check that the upper pivot of the
generating rotor is inserted properly into the
pivot jewel.
· Be sure to lubricate the upper and lower pivots
of generating rotor and intermediate wheel for
generating rotor with the proper oil in the
quantity specified in the illustration.
· Lubricate the ball-bearing of the oscillating
weight bridge as shown in the illustration at
right.
Intermediate wheel for
generating rotor
Generating rotor
25 Generating coil block
The generating coil block for Cal. YT57B and that for Cal. 5M4 Series have a close resemblance in shape.
They can be discriminated by the size of the pattern on the lead terminal. If the generating coil block
for Cal. 5M4 Series is assembled by mistake, no electricity will be generated. When repairing the
generating coil block, check the size of the pattern on the lead terminal to make sure you are using the
proper one.
Smaller pattern Larger pattern
[ Generating coil block for Cal. YT57B ] [ Generating coil block for Cal. 5M4 Series ]
26 Intermediate wheel for generating rotor
•Lubricating
Refer to the illustration at right.
Note: Be sure to observe the position, type of oil
and quantity of the lubrication specified
in the illustration.

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TECHNICAL GUIDE Cal. YT57B
35 Fourth wheel and pinion
36 Third wheel and pinion
37 Fifth wheel and pinion
38 Step rotor
39 Minute wheel
40 Setting wheel
•Setting position and lubricating
Refer to the illustrations below for the setting position and lubrication of the respective wheels.
Lubricating: : Moebius A : Moebius F
Fifth wheel
and pinion
Step rotor
Setting wheel
Fourth wheel
and pinion
Minute wheel
Third wheel
and pinion
Center wheel
and pinion
Step rotor Fifth wheel and pinion Fourth wheel and pinion Third wheel and pinion
46 Center wheel and pinion
Note: Be sure to observe the position, type of oil
and quantity of the lubrication specified in
the illustration.
Minute wheel
Setting wheel

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TECHNICAL GUIDE Cal. YT57B
Lubricating: : Moebius A : SEIKO Watch Oil S-6
33 Train wheel setting lever
41 Yoke
42 Setting lever
•Setting position and lubricating
Refer to the illustration at right.
Train wheel setting lever
Setting lever
Yoke
III. VALUE CHECKING AND ADJUSTMENT
●Coil block resistance
1.7 KΩ~ 2.1 KΩ
●Generating coil block resistance
280 Ω~ 380 Ω
●Current consumption
For the whole movement : Less than 0.80 µA (with 1.55 V supplied from a battery)
For the circuit block alone : Less than 0.20 µA (with 1.55 V supplied from a battery)
1. Make the movement ready for measurement.
How to measure the current consumption for the whole movement
1) Follow the disassembling procedure
illustrated in this manual until you remove
the rechargeable battery unit.
2) Temporarily tighten the screw “A” in the
illustration, taking care not to tighten it
excessively.
3) Install the oscillating weight wheel and
oscillating weight and then tighten the
oscillating weight screw.
Screw “A”

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TECHNICAL GUIDE Cal. YT57B
2. Apply the minus terminal to “a” portion of the
input terminal (–) in the illustration and plus
terminalto thecircuit blockcover, respectively.
“a” portion
Circuit block cover
Note: When moving the oscillating weight
from side to side, take care lest the
minus terminal of the tester touches the
oscillating weight.
3. For a few seconds after the probes of the tester
are applied to the movement, the IC is in the
quick start mode, and current consumption
cannotbe measured properly. Toswitchthe IC
from the quick start to the normal hand
movement mode, move the oscillating weight
from side to side continuously for more than
three seconds with the tester connected to the
movement. The IC will detect the electricity
generation and will be switched to the normal
hand movement mode.
4. After checking that the IC has been switched to the normal hand movement mode and a stable
measurement can be obtained, read the measurement.
If the measurement value remains high or unstable, repeat step “3” above.
Notes:
* Light may increase the current consumption, resulting in an inaccurate measurement. If the current
consumption exceeds the standard value, protect the movement from light with a black cloth or the
like, and make a measurement again.
* When the current consumption for the whole movement exceeds the standard value while the current
consumption for the circuit block alone is within the standard value range, a driving pulse may be
generated to compensate for the heavy load applied on the gear train, etc. In that case, overhaul and
clean the movement parts, and then, measure the current consumption for the whole movement again.
1. Connect the tester to the
circuit block as shown in the
illustration.
How to measure the current consumption for the circuit block alone
“A” portion

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TECHNICAL GUIDE Cal. YT57B
2. With the tester connected to the circuit block, short-circuit “A” portion in the illustration and the input
terminal(–)with conductive tweezersor the likeformore than 3seconds. The IC willbeswitched from
the quick start to the normal hand movement mode.
3. Checking that a stable measurement is obtained, read the current consumption.
If the measurement value remains high or unstable, repeat step “2” above.
Note: The current consumption measurement for the circuit block alone is particularly susceptible to
light, and a value higher than the actual measurement may be obtained if the circuit block is
exposed to light. Protect the circuit from light with a black cloth or the like after following step “2”
above, and then, measure the current consumption.
●Checking the automatic generating system
1. Apply the probes of the tester as shown in the
illustration, and measure the voltage of the
rechargeablebattery. Theobtainedvoltageis called
the “initial voltage”.
Notes:
* When applying the minus probe of the tester to
the rechargeable battery, take care not to short-
circuit the lead terminal (–) and the rechargeable
battery clamp.
* If a short-circuit has occurred, leave the watch
untouchedformorethan10minutes,andmeasure
the voltage again, checking that a stable
measurement is obtained.
2. Close the case back tentatively, and swing the
watch from side to side 200 times at a rate of 2 to 3
swings a second, making an arc of approximately
20 cm.
3. Within3minutesafter swingingthewatch,measure
the voltage of the rechargeable battery in the same
manner as in step “1” above.
4. Refer to the table below, and decide whether the
automaticgeneratingsystem isnormalor defective.
[ For your information ]
●Number of swings and power reserve
· When the power reserve in the rechargeable battery is depleted and the watch stops completely,
swingingit approximately 100times at arate of 2to 3timesa secondwill start thesecond hand moving
at normal one-second intervals instead of two-second intervals. There will be about 12 hours of power
reserve available. If the second hand still moves at two-second intervals after 100 swings, swing the
watch further until it moves at one-second intervals.
· While the second hand is moving at one-second intervals, 200 to 250 swings will reserve up to one
day of power.
Initial voltage Guidelines of normal/defective decision
[ Initial voltage and guidelines of normal/defective decision ]
0.45 V ~ 1.0 V After charging, the voltage of rechargeable battery has increased 0.2 V or
more from the initial voltage.
1.01 V ~ 1.2 V After charging, the voltage of rechargeable battery has increased 0.1 V or
more from the initial voltage.
* The guidelines specified in the above table apply only when the initial voltage is within the range between 0.45
V and 1.2 V.
* The amount of electricity generated by swinging the watch varies depending on the manner in which you swing
it, such as the rate of swinging and the size of the swinging arc. Please note, therefore, that checking through
the procedure above provides only the guideline of normal/defective decision.
* Printed on recycled paper. 99-12 Printed in Japan