National 167 Series - User Manual

Questions and Answers

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Randy HartmanAug 14, 2025
Why does the light fail to operate on my National 167?
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  William RiveraAug 14, 2025
  If the light on your National Microscope fails to operate, several factors could be at play. First, ensure the AC power cord is securely connected to the outlet. If it is, the outlet itself might be inoperative, requiring repair by a qualified technician. A burned-out lamp or fuse could also be the culprit, necessitating replacement. If the fuse burns out too quickly, try replacing it with a time-delay fuse. If the fuse blows instantly upon replacement, the unit likely has a short and needs professional repair. Finally, verify that you're using the correct lamp with the proper voltage and base; if not, replace it with the specified lamp.
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Michelle WilkinsonAug 17, 2025
How to improve poor resolution (image not sharp) on National Microscope?
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  Cynthia WellsAug 17, 2025
  If the image on your National Microscope is not sharp, it could be due to several reasons. Start by cleaning the objective lens and eyepiece lens. Ensure the specimen slide is oriented correctly with the cover slip facing up. If using a cover slip, make sure it's 0.17mm thick. Too much light can also cause poor resolution, so adjust the light intensity to a lower setting. Clean the condenser lens as well. Lastly, check that the rack stop is set properly and adjust if needed.
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mjohnsonAug 20, 2025
What to do if the light flickers on my National Microscope?
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  Alyssa EdwardsAug 20, 2025
  If the light flickers on your National Microscope, there are a few things you can check. Ensure the lamp is properly inserted into the socket. If it's still flickering, the lamp may be nearing the end of its life and should be replaced. Also, verify that the fuse holder is correctly locked into position. A loose connection at the AC outlet can also cause flickering, so have a qualified service technician repair the outlet if necessary.
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Elizabeth MortonAug 25, 2025
Why does the light bulb burn out immediately on my National 167?
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  Ryan SmithAug 25, 2025
  If the light bulb in your National Microscope burns out immediately, it might be due to using the incorrect lamp. Make sure you are using the proper lamp (12 volt 20 watt). Also, ensure that the unit is plugged into the correct outlet (120v or 220v).
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Joshua SmithAug 27, 2025
How to remove spots in field of view on National 167?
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  Carlos AlvarezAug 27, 2025
  If you observe spots in the field of view of your National Microscope, the issue is likely due to dirty lenses or slides. Begin by cleaning the eyepiece lenses. If the spots persist, clean the specimen slide. Should the problem continue, proceed to clean the condenser lens.
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Natalie LindseyAug 31, 2025
Why is there uneven illumination of field on National 167?
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  lewisdavidAug 31, 2025
  If you're experiencing uneven illumination of the field on your National Microscope, the nosepiece may not be properly indexed. Revolve the nosepiece until it clicks into the positive index stop. Additionally, the diaphragm might not be correctly indexed, so adjust the iris diaphragm to the proper level.
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Katrina RobertsSep 3, 2025
How to prevent the light from burning out too soon on National Microscope?
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  Jesse AndersonSep 3, 2025
  If the light in your National Microscope burns out too soon, the voltage may be too high. To resolve this, adjust the intensity control to the minimum position before turning the power switch on.
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Ashlee WrightSep 6, 2025
What to do if there is no image on National 167?
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  Daniel ReynoldsSep 6, 2025
  If you are getting no image on your National Microscope, the nosepiece may not be indexed properly. Move the revolving nosepiece until the objective lens clicks into position. Also, the light might be too bright, so adjust the light intensity control to a lower position.
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Eduardo CarterSep 10, 2025
How to fix a National 167 that does not stay in focus?
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  Kari LewisSep 10, 2025
  If your National Microscope does not stay in focus, and the stage drops down, adjust the tension adjustment knob.