The LaCie F800 uses a small battery to retain several settings. Over time, all batteries fail and require replacement. The LaCie F800 uses a Maxell CR2032 3V, Mitsubishi CR2032E 3V or compatible battery. The procedure below demonstrates the proper method to change the battery:
STEP 1 - Disconnect all cables from the F800. Remove the 4 silver screws around the fan opening. DO NOT remove the black rivets.
STEP 2 - Locate the battery on the circuit board.
STEP 3 - Press the tab to remove the battery. Replace it with a new battery. Reverse the process to reassemble.