CASIO QW1644 (SM552)
Service Manual

6. PRECAUTIONS FOR REPAIR : QW-1619 / 1622 / 1644 6-1. AC (ALL CLEAR) AND REMOVING OF MODULE
1.Perform AC (ALL CLEAR) when inserting a new battery, or else the memories and/ or counters may give erratic displays. Touch the AC contact and the positive (+) side of the battery or main plate with the metalic tweezers. The contact should be made for about two seconds. For 2 seconds after the AC operation, do not make any button operations on these modules. 2.On removing of the module from the case, please insert the precision screw driver between the module and the case pointed by arrows.

Metallic tweezers

6-2. ACCURACY CHECKING
Check the accuracy of the module with the quartz timer after switching the module to "ACCURACY CHECKING MODE". The operations are shown below: A) SWITCHING TO "ACCURACY CHECKING MODE" Keep pushing the D button and continuously push the A , C buttons at the same time at the normal time keeping mode. Then all the segments are displayed and the LCD drive signals are changed to the static drive signal of "32 Hz" so that you can check the accuracy with the quartz timer. B) CANCELLATION OF THE "ACCURACY CHECKING MODE" Push any button except D . Then the display is returned to its original state. NOTE: The "ACCURACY CHECKING MODE" will automatically return to the regular mode in 1 ~ 2 hour(s) without any operation.
QW-1619 / 1644 QW-1622

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