Maintenance notes for microscopes from Leitz' "black era" (170 mm tube length) Eyepiece Collimation of Leitz Black Era Microscopes Leitz 600 Series Condenser Leitz Berek Condenser Leitz Ortholux Focus Mechanism (pre-1953) Leitz Ortholux Focus Mechanism (post-1953) Leitz Ortholux Nosepiece Leitz Ortholux XY-Stage Seized Diopter Adjustment on an Eyepiece Tube (Leitz Black Era) Leitz 6V 30W Lamphouse Condenser Holders for Leitz Microscopes with 170 mm tube length Ortholux Front End Illumination System (pre-1963/64) Ortholux Front End Illumination System (post-1963/64) Leitz 40x and 63X apochromatic objectives with sluggish cover glass thickness adjustrment