These are all problems that can be corrected with a yearly appointment to clean and adjust your microscope. Dust or solutions settle on optical surfaces and a yearly cleaning is required to keep your microscope operating properly. Fresh lubrication is a critical element to maintaining the gear assemblies and bearing track in your microscope. Over a period of time the lubrication breaks down or hardens and the increased friction in these components can damage gears and bearings. Shadows or uneven illumination in the field of view can be corrected by aligning the bulb and optical pathway. New brightfield or fluorescent bulbs can be installed at the time of cleaning. The best way to optimized the performance of your microscope and minimize costly repairs is to schedule a yearly cleaning.