Casio ABX-68B, Repair Manual, Page: 14 / 52

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4. Accuracy Setting Method for Casio Watches
Although the oscillation frequency of the oscillator/quartz used in watches is said to be 32,768 Hz, in
actuality there is a slight degree of variation between individual oscillators/quartz. Accuracy setting is
required in order to maintain the accuracy claimed in the specifications of watches using these oscil-
lators/quartz.
This accuracy setting procedure is naturally also required when a oscillator/quartz has been replaced
during repairs.
The following provides a description of the accuracy setting method for Casio watches.
4-1 Accuracy Setting by Capacitor/Trimmer
Tool used
The capacitor/trimmer is a capacitor equipped with a
volume that enables the capacitance to be varied.
When the accuracy of a watch is measured with a
quartz timer and the accuracy is found to be incor-
rect, accuracy can be adjusted by turning the volume
of the capacitor/trimmer.
This procedure must always be performed when the watch no longer keeps the correct time or after
the oscillator/quartz has been replaced. Furthermore, the accuracy (monthly) and setting range (daily)
of each watch (module) is indicated in the Specifications of the Service Manual or the List of Current
Consumption in Watch Index Book.
In the case of a watch accurate to a monthly error of
±
15 seconds, the daily error is normally set to a
range of +0.25 to +0.35 seconds.
This is done in consideration of the temperature characteristics of the oscillator/quartz. Even if the
watch were set to be accurate to a daily error of
±
0 seconds, the watch would end up running slow at
atmospheric temperatures outside the vicinity of 25
°
C. Watches are therefore set to a range of +0.25
to +0.35 seconds at the outset to enable them to maintain a constant accuracy (
±
15 seconds) within
an atmospheric temperature range of 0-40
°
C. (Fig. 4-2)
Fig. 4-1
Fig. 4-2
Quartz timer
32,768=0
25
°
C
°
C
NO. Code No. Tool name
1 Quartz timer
2 1901 9523 Precision tweezers
3-1 1704 1667 Soldering iron (110 V/117 V)
3-2 1904 1668 Soldering iron (220 V)
4 1901 9868 Solder wick
5 1901 9401 Solder
6 1901 9975 Ceramic screw driver (small)