Compound Microscope Troubleshooting

There are many difficulties that a microscope user might encounter before even trying to see the specimen. Dirty lenses and problems controlling the light source are common. Here is how to avoid these frustrating scope issues.

* Clean All Lenses First *

To avoid problems with object clarity, always clean the lenses of a compound microscope before trying to view the specimen. Use lens paper to carefully wipe the ocular lenses and also the objective lenses attached to the nose piece, keeping in mind that the lens openings for the higher power objectives are very small, and a bit tricky to clean.

* Microscope Power Cord *

Some scopes have the power cord permanently attached. Others have a separate cord, which may be stored in a different location than the microscopes. If the cord is separate, make sure that, once it is retrieved, it is securely connected to both the scope and the outlet.

* The Light Is Not Turning On! *

So the lenses are clean, the scope plugged in, the power switch is then toggled, and…nothing. The light doesn’t turn on. What’s up?

Most people assume that, if no light appears when the scope is switched on, the bulb is burned out, but this is usually the least likely culprit. First, there are a few other possibilities to check:

Light Adjustment Dial in Microscope Base: Although the location of the light control may vary, depending on the scope manufacturer, there is typically a dial in the base of the microscope that is used to adjust the brightness of the light source. If it is turned all the way down, there will be no light.

No Power from Outlet: If the light control dial is turned completely in both directing, and no light appears, try plugging the microscope into a different outlet; and not just the other outlet in a double. Both may not be working. Try a completely different set.

Adjusting Light With Iris Diaphragm: Perhaps there is light shining from the microscope’s light source, but it’s not making it through to the specimen? If this is the case, the aperture beneath the stage, called the iris diaphragm, may be closed. Like the iris of the eye, the microscope’s iris diaphragm can be opened and closed — adjusted to let in more or less light. If the aperture is closed all the way, light will not pass through the specimen to illuminate it.