Summarize some common faults and repair methods of microscopes
1. Coarse adjustment failure
The fault phenomenon is that when the coarse focus screw is turned, the lens barrel cannot rise or fall accordingly. The lifting and lowering of the Olympus microscope mirror is achieved by driving the gear bar, and the gear is fixed on the rotating shaft of the coarse adjustment knob, and the rack is fixed on the lens barrel. When the coarse adjustment knob is turned, the gear drives the bar to raise and lower the lens barrel. If the lens barrel cannot be raised or lowered accordingly, it means that the gear and rack are not aligned. The common cause of failure is that the gear rod sleeve rotates with the coarse adjustment knob, that is, the two stop screws on the gear rod sleeve do not fix the gear rod sleeve on the dovetail guide rail. The repair method is to move the gear to the middle of the gap in the gear rod sleeve, and let the gap in the gear rod sleeve face the rack, and then use a small screwdriver to tighten the two stop screws on the end face of the tail guide rail. If it does not work, it means that the rack is severely worn. You need to remove the lens barrel, unscrew the upper and lower fixing screws of the rack, and use the rack upside down, because rack wear mainly occurs in the upper part of the rack. Or cut a metal sheet according to the width of the rack, let the metal sheet be embedded on the rack, fix the sheet and rack on the lens barrel with fixing screws, and insert it into the lens barrel for debugging. If you feel any tightness, you can change the thickness of the metal sheet until it is suitable. Or purchase a new rack from the manufacturer according to the original model specifications.
2. The lens barrel slides down on its own
The fault phenomenon is that when the focus is aligned and the focus screw is released, the lens will slide down on its own, causing the focus to be inaccurate. In the coarse adjustment structure of the microscope, the tightness of the gear shaft is generally controlled by the friction between the gear rod sleeve and the coarse adjustment knob, while the friction between the gear shaft and the gear rod sleeve is controlled by the two parts connected to the gear shaft. A coarse adjustment button is obtained by pressing two plastic washers tightly against the end face of the gear rod sleeve. The tighter the grain is rotated or pressed against the end face of the gear rod sleeve, the greater the friction force obtained. The reason why the lens barrel slides down on its own is because the washer is worn and deformed after being used for a long time, which reduces the friction between the gear shaft and the gear rod sleeve. The torque generated by the friction between the gear shaft and the gear rod sleeve cannot overcome the gravity of the lens barrel itself. caused by the torque generated. The repair method is to hold one side of the coarse adjustment knob with both hands and tighten the coarse adjustment knob in a clockwise direction. If it doesn't work, the gasket needs to be thickened. Insert needle-nose pliers into the double-eye nut on the end face of any coarse adjustment knob, unscrew it, remove the coarse adjustment knob, take out the plastic washer, use green shell paper or thin plastic sheet to cut a washer with the same diameter, sandwich it between the original washer and between the coarse adjustment knob and reinstall it. If it is difficult to turn the coarse adjustment knob, it means that the washer is too thick. You should replace it with a thinner one. In short, if there is a certain resistance when turning the coarse adjustment knob, the lens barrel will not move easily. The decline shall prevail.
