Reducing the microscope can turn off the built-in light source and unplug the power plug, or make the mirror perpendicular to the condenser. Rotate the objective lens converter so that the position of the objective lens is open and opposite to the light hole. Then adjust the distance between the lens barrel and the stage to the nearest distance, and lower the condenser.
The main problem of coarse tuning is that the tightness is different when it slides down or rises and falls automatically. The so-called automatic sliding refers to the phenomenon that the lens barrel, the lens arm or the stage automatically falls slowly without adjustment under the action of its own weight.