Key Sensor - Yamaha disklavier Mark III Series Maintenance Handbook

A display similar to the following appears, with the clock stopped and the hours display flashing.
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Use [ ] and [
and [+/YES] buttons to set a value.
Pressing both [–/NO] and [+/YES] simultaneously in each respective field sets the year to 1990, month and
day to 1, and the hours, minutes, and seconds to 0.
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Press [ENTER].
The date and time are stored in the internal calendar, and the display returns to the current time display.
Calendar Memory
The date and time that you set are saved in the calendar memory when you turn off the Control Unit. The
calendar memory can maintain the correct date and time for about a month. If you do not use the Control
Unit for over a month, you must reset the calendar following the above procedure.
Note: The internal calendar is equipped with a storage battery (capacitor) that does not need to be
replaced or recharged. However, the Control Unit must be turned on for at least 10 minutes a month
in order to maintain power.

2. Key Sensor

The key sensor is a single-beam continuous-position optical sensor.
This sensor provides a sensor calibration function.
When the key sensor unit is manufactured, the change in the beam as the shutter moves from its open to
its close position is measured over the full stroke for each key, and the curve for each key is recorded on
the sensor sheet.
Then, after the sensor is installed in the piano, the beam is measured for open, key rest, and key stroke
end locations; the open, rest, and end are plotted, and K1~K4 are assigned.
This means that in contrast to the 2-beam 4point optical sensor, it is possible to accurately detect the
performance data in spite of unevenness in the beam for each key or unevenness in the state of the shut-
ter.
Sensor Measurement and Sensor Manual Adjustment are built into the test mode sensor sheet.
(refer to Test Mode)
This measurement is performed at the factory when the sensor is installed in the piano, and will nor-
mally not be necessary in the market. However if the sensor unit is exchanged, this measurement must
be performed.
Also, if there are significant differences in the volume of the electronic sound or piano playback sound
between keys, check Acoustic Regulation and sensors, drive units, and perform the measurement.
Flashes
] to select year, month, date, hours, minutes, and seconds, and use the [–/NO]
ENTER
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–/NO +/YES