Casio fx-7400G Service Manual & Parts List page 7

• To replace the memory back up battery
1 Press to turn the calculator off.
SHIFT OFF
2 Push the battery compartment cover on the
back of the calculator in the direction noted in
the illustration and remove it.
3 Remove screw D on the back of the calculator,
and remove the back up battery holder.
4 Remove the old battery.
5 Wipe off the surfaces of a new battery with a
soft, dry cloth. Load it into the calculator so that
its positive + side is facing up.
6 Pressing down on the battery with the battery
holder, replace the screw that secures the
holder in place.
7 Replace the battery compartment cover and
press to turn power on. The main battery
AC/ ON
provides power to the memory while the back-
up batteries are removed, so memory data is
not lost.
REMARK
* Before replacing the memory back up battery, turn on the unit and check to see if the "Low battery!"
message appears on the display. If it does, replace the main power supply batteries before replacing
the back up power supply battery.
* Never remove the main power supply and the memory back up batteries from the unit at the same time.
* Be sure to switch the unit off before replacing batteries. Replacing batteries with power on will cause
data in memory to be deleted.
* Be sure to replace the back up power supply battery at least once 2 years, regardless of how much
you use the unit during that time. Failure to do so can cause data in memory to be deleted.
Important
Data stored in memory can be corrupted or lost if battery power drops below a certain level. When this
happens, you must perform the RESET operation to restore normal operarion. Note that the RESET
operation clears all data from memory. Because of this, you should be sure to keep written copies of
all important data to avoid losing it due to low battery power.
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