Canon EOS-1D C - Manual (Page 366)

366
The date/time (backup) battery maintains the camera’s date and time.
Its service life is approx. 5 years. If the date/time is reset when camera
is turned on, follow the procedure below to replace the backup battery
with a new CR2025 lithium battery.
The date/time/zone setting will also be reset, so be sure to set the
correct date/time/zone (p.40).
1
Set the power switch to <2>.
2
Remove the battery.
The backup battery is on the ceiling of
the battery compartment.
3
Remove the back-up battery
cover.
Use a small screwdriver to loosen the
screw and remove the cover.
Be careful not to lose the cover and
screw.
4
Remove the battery.
Stick a piece of tape to the battery
and take out the battery.
5
Install a new back-up battery.
The plus side of the battery must face
up.
6
Attach the cover.
Replacing the Date/Time Battery
(+)
For the date/time battery, be sure to use a CR2025 lithium battery.
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