How To Wind The Mainspring; Power Reserve Indicator; How To Read The Power Reserve Indicator - Seiko 6R20 Instructions Manual

How to wind the mainspring

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• This is an automatic mechanical watch with a manual winding mechanism.
• When the watch is worn on the wrist, the mainspring is wound automatically through normal wrist
movement. The watch can also be wound up by turning the crown.
• To start the watch after it stops completely, wind it up either by turning the crown or swinging it from side
to side until the seconds hand starts moving. Then, set the time and date before putting the watch on
the wrist. To wind up the watch, turn the crown clockwise slowly. The watch cannot be wound by turning
the crown counterclockwise. In this way, the watch can be wound up fully. Furthermore, turning the crown
further will not break the spring.
* For the watch with screw down crown, please unlock the crown before operating it and be sure to lock the crown
after operating it.
• Wind the mainspring until the power reserve indicator shows a fully-wound state. Once the watch is
wound up fully, it operates for about 45 hours.
* To check the winding state of the mainspring, refer to "Power reserve indicator" → P.14.
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Power reserve indicator

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• The power reserve indicator lets you know the winding state of the mainspring.
• Before removing the watch from your wrist, observe the power reserve indicator to check if the watch
has stored enough power to keep running until the next time you wear it. If necessary, wind the
mainspring. (To prevent the watch from stopping, wind the mainspring to store the excess power that
will allow the watch to run for extra time.)
* The continuous operating time of the watch may vary depending on the conditions of your usage (such as the
number of hours you wear the watch or the extent of your movement while wearing it).
* In a case where you wear the watch for a short period of time each day, observe the power reserve indicator to
check the level of the remaining power. If necessary, manually wind the mainspring.
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* If the watch is used without being wound up fully, gain or loss of time may result. To avoid this, wear the watch for
more than 10 hours a day. If the watch is used without being worn on the wrist, be sure to wind it up fully every day
at a fixed time.
* If you use a watch that has stopped with the mainspring unwound, winding the mainspring with the crown will not
start the watch immediately. That is because the mainspring torque or force is low at the beginning of its winding
due to the characteristics of mechanical watches. The seconds hand will start to move when a certain degree of
torque is reached after the mainspring has been wound up. However, swinging the watch from side to side to
forcibly turn the balance can start the watch sooner.

■ How to read the power reserve indicator

• As shown in the diagram below, when the indicator is pointing near 45 or F on the scale, it is fully wound.
As the mainspring unwinds, the indicator will move toward 0 or E.
* The accuracy of a mechanical watch is affected by the winding amount of the mainspring. If the watch is used
for a long time when the winding amount is 20 hours or less, stable accuracy may not be obtained. Therefore,
it is recommended that the winding amount be between 20 hours and full winding when you use the watch.
* Once the mainspring is fully wound, it will slip if you wind it further, so there is no chance of the mainspring
breaking even if it is over wound.
* The indicator may move beyond 0 or E, but this is not a malfunction.
The Power
Reserve Indicator
The winding state
Fully wound Half wound
of the mainspring
The number of Approximately 45 hours Approximately 20 hours
hours the watch
can run
* Designs vary depending on the model. Refer to the above diagram to read the approximate continuous operating
time.
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Unwound
The watch either stops or is
running down.
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