Nikon d3s User Manual (en)

If the camera fails to function as expected, check the list of 
common problems below before consulting your retailer or Nikon 
Viewfinder is out of focus
: Adjust viewfinder focus or use optional diopter 
adjustment lenses (
0 41, 373).
Viewfinder is dark
: Insert a fully-charged battery (
0 26, 43).
Displays turn off without warning
: Choose longer delays for Custom Setting c2 
(Auto meter-off delay) or c4 (Monitor off delay) (
0 305, 306).
Unusual characters displayed in top control panel
: See “A Note on Electronically-
Controlled Cameras,” below.
Displays in control panels or viewfinder are unresponsive and dim
: The response 
times and brightness of these displays varies with temperature.
A Note on Electronically-Controlled Cameras
In extremely rare instances, unusual characters may appear in the 
monitor or top control panel and the camera may stop functioning. In 
most cases, this phenomenon is caused by a strong external static 
charge. Turn the camera off, remove and replace the battery, and turn 
the camera on again, or, if you are using an AC adapter (available 
separately), disconnect and reconnect the adapter and turn the camera 
on again. In the event of continued malfunction, contact your retailer or 
Nikon-authorized service representative. Note that disconnecting the 
power source as described above may result in loss of any data not 
recorded to the memory card at the time the problem occurred. Data 
already recorded to the card will not be affected.