Maintenance & Troubleshooting
The microscope is the workhorse of the cytogenetics laboratory. Neglect leads to image degradation, eye strain, and costly repairs. A proactive maintenance schedule and a logical troubleshooting approach are essential for daily operations
Daily Maintenance (The “Shut Down” Protocol)
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Cleaning Oil: Immersion oil is acidic and sticky. If left on the lens overnight, it can seep into the lens housing, dissolving the cement that holds the optical elements together
- Protocol: After every session, wipe the 100x objective with proper Lens Paper. Do not use Kimwipes (too rough) or facial tissue (lint)
- Solvent: If oil has dried, use a small amount of lens cleaner (or alcohol mixture). Do not soak the lens
- Protection: Lower the stage and cover the microscope with a dust cover. Dust is the enemy of optics; it settles on prisms and creates permanent shadows
- Lamp Care: Turn off the light source (unless it’s an LED) to conserve bulb life. Avoid toggling halogen bulbs on/off rapidly, as this shortens filament life
Periodic Maintenance (Preventative)
- Kohler Check: Verify Kohler illumination alignment weekly. It drifts as users adjust the condenser
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Eyepiece Cleaning: Mascara, oils from eyelashes, and skin flakes accumulate on the eyepieces
- Cleaning: Use a cotton swab with lens cleaner to gently wipe the ocular lens in a spiral motion from the center outward
- Stage Movement: Clean the mechanical stage gears. If the stage feels “gritty” or drifts, it may need re-greasing (by a service pro)
- Professional Service: An authorized engineer should service the microscope annually to clean internal prisms, align the optical path, and lubricate mechanical parts
Troubleshooting Common Issues
When the image looks bad, do not panic. Follow the light path from the source to the eye to find the culprit
Problem 1: “I can’t see anything” (Black Field)
- Check: Is the light on?
- Check: Is the objective clicked into place? (Often it’s stuck between 10x and 100x)
- Check: Is the camera pull-rod engaged? (Diverting 100% light to the camera and 0% to eyes)
- Check: Is the Field Diaphragm closed completely?
Problem 2: The image is blurry / hazy (Low Contrast)
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Cause: Dirty Objective. This is the #1 cause. A film of oil on the 40x or 100x lens ruins contrast
- Fix: Clean the lens thoroughly
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Cause: Dirty Slide.: Fingerprints or oil on the cover of the slide
- Fix: Clean the slide
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Cause: Condenser Height.: If the condenser is too low, resolution drops
- Fix: Adjust Kohler (raise condenser)
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Cause: Upside Down Slide.: You are focusing through the thick glass slide instead of the thin coverslip. The 100x lens cannot reach the focal plane
- Fix: Flip the slide over
Problem 3: Shadows or Specks in the Field
To find the dirt, move the components one by one:
- Rotate the Eyepiece: If the speck rotates, the dirt is on the eyepiece
- Move the Slide: If the speck moves, it’s on the slide
- Rotate the Objective: If the shadow changes, it’s on the objective
- Adjust Condenser: If the speck goes in and out of focus when you move the condenser, it’s on the condenser lens or light exit