The primary maintenance procedures that are outlined in the manual are for the bio-wiper (shutter) installation, the internal battery replacement and the bulkhead connector inspection. The shutter replacement is not always necessary; however, having the copper shutter and face plate parts available to swap out as needed is a good idea.
Otherwise, the optics face should be inspected for film/streaks. The wiper may not work effectively if the copper faceplate condition deteriorates and damages the rubber blade. Some environmental conditions can start to "pit" the face plate surface, shredding the wiper blade. Replacing the face plate should be done if the wiper blade is getting damaged by being dragged across it. Otherwise, cleaning the active optics sensor area usually only requires DI water and a lab wipe (i.e. Kimwipe). Superficial scrapes and scratches on the optics face are unlikely to significantly affect the measurement.
Working with the shutter, moving it for inspection and/or removing it to install a new one, requires the instrument to be powered ON... keeping power to the shutter motor and commanding the open/close positions via software command/control. When moving/removing the shutter, it should NOT BE MOVED MANUALLY! There are gears in the ECO shutter motor that can strip easily with the wrong manual motion, unpowered. The manual motion in the wrong direction and speed, can overcome some of the gear ratios at play when they are back-driven.
Terminal emulator programs (as opposed to ECO View) are the most direct platform for working with the ECO's. However, their use depends on one's preference for how to interface with the instruments.