Dell S510 Interactive Projector - Manual (Page 34)

34 Using Your Projector
Replacing the Interactive Pen Batteries
NOTE: If the battery is low, the LED indicator starts flashing red as
you turn on the pen. You should replace with two new AAA batteries.
1 You can access the battery compartment by turning open the pen head.
2 Check the polarity (+/-) marking on the batteries.
3 Insert the batteries and align their polarity correctly according to the
marking on the pen head.
NOTE: Avoid mixing different types of batteries or using new and
old batteries together.
4 Place the pen head back, turn until the battery compartment access fully
closed.