Casio 3179 Manual page 42

Auto light switch precautions
• Avoid wearing the watch on the inside of your wrist. Doing so causes the auto light
switch to operate when it is not needed, which shortens battery life. If you want to
wear the watch on the inside of your wrist, turn off the auto light switch feature.
E-40
• Illumination may not turn on if the face of the watch is
more than 15 degrees above or below parallel. Make
sure that the back of your hand is parallel to the ground.
• Illumination turns off after the preset illumination
duration (see "To specify the illumination duration" (page
E-30)), even if you keep the watch pointed towards your
face.
• Static electricity or magnetic force can interfere with
proper operation of the auto light switch. If illumination
does not turn on, try moving the watch back to the
starting position (parallel with the ground) and then tilt it
back towards you again. If this does not work, drop your
arm all the way down so it hangs at your side, and then
bring it back up again.