Levenhuk 870T Biological Trinocular Microscope: Troubleshooting

Assemble the binocular head. Loosen the locking screw and remove the plastic cover from the arm. Remove the plastic 

cover from the binocular head. Attach the binocular head to the arm and secure it in place with a locking screw. Do not 

try to loosen the other two screws on the arm.

Assemble objective lenses. Usually, we assemble the objective lenses on the factory lines, but in some models, they are 

shipped separately. First, remove the dust cap from the nosepiece and take out the objective lenses from their packaging. 

Attach the objective lenses to the nosepiece in ascending order (from lowest magnification to highest).

Assemble

eyepieces

. 

Remove the dust cap from the tube and attach the eyepieces.

Choose a spot, where the microscope will not be in direct sunlight. Try to move as far away from windows as possible and 

do not point eyepieces toward windows. Direct sunlight may damage the optics and lower the contrast of images.

Place a slide with a specimen on the stage and lock it in place. Make sure that the cover glass faces upwards, otherwise, 

you might have problems focusing your view at higher magnifications (40x or 100x).

Use a low-power objective lens (4x or 10x) and turn the illumination on.

Using the coaxial stage movement controls, position the slide, so that the specimen is centered above the condenser lens.

Focus your view with the coarse focus knob. It is much easier to focus your view at lower magnifications, so that when you 

use a high-power objective lens, you will only have to fine-tune the focus with the fine focus knob.

Now that your view is focused, rotate the revolving nosepiece to a high-power objective lens. Thanks to the parfocal 

lenses in these microscopes, you will only have to use the fine focus knob to bring your views into focus. It has to be 

mentioned that 4x and 10x objective lenses will never touch the surface of the slide, due to the built-in limiters. And 

although 40x and 100x may reach the slide, thanks to their spring-loaded construction, they will never break it.

If

you

cannot

focus

your

view

, 

you

might

want

to

try

changing

the

diameter

of

the

iris

diaphragm

, 

so

that

it

corresponds

to

the

N

.

A

. 

of

the

objective

lens

used

.

Using the microscope

If you are experiencing some problems with your instrument during its service, refer to this section for possible solutions. 

However, if this doesn't help, you should contact your local service center. Remember, do not try to take the microscope 

apart, as this will make your warranty null and void, as well as may lead to irreversible damage to the intricate optical 

system of the instrument.

Troubleshooting

Problems with the microscope:

Problem

Possible cause

Solution

Impossible to focus the view

The stage is too low

Raise the stage with the coarse focus knob

The objective lens often damages slides

The stage is too high

Lower the stage with the fine focus knob

Impossible to focus the view when using 

high-power objective lenses

The slide may have been placed upside 

down, or the cover glass is too thick 

Place the slide properly or opt for a 

standard cover glass (0.17 mm (0.007 in) 

thick)

When rotating the nosepiece, objective 

lenses always scrape the surface 

The cover glass is too thick

Opt for a standard cover glass (0.17 mm 

(0.007 in) thick)

Impossible to move the slide smoothly

The stage clips are not locked

Lock the stage clips manually

Incomplete binocular vision

Incorrect interpupillary distance

Adjust the interpupillary distance

Incomplete diopter adjustment

Readjust diopter settings

Insufficient brightness

Check the illumination source and readjust 

the brightness

Problems with the optical system:

Problem

Possible cause

Solution

The field of view is 

reduced or not fully 

illuminated

The objective lens is not locked in place

Rotate the revolving nosepiece to lock the desired 

lens in place

The optical axis is not aligned

Readjust the illumination lamp

The optics of the objective lens is dirty or dusty

Clean the objective lens

The field of view is 

reduced or not fully 

illuminated

The optics of the objective lens is dusty or dirty

Clean the objective lens

The surface of the slide is dusty or dirty

Clean the slide

The condenser lens is too low

Raise the condenser lens

Poor

quality

of

views

: 

reduced

contrast

, 

blurred

details

, 

etc

. 

The specimen is not protected with cover glass

Put the cover glass over the specimen

The cover glass is too thick or too thin

Opt for a standard cover glass (0.17 mm (0.007 in) 

thick)

The slide is placed upside down

Place the slide correctly

The upper lens of the objective lens is dirty

Clean the lens

The optics of the objective lens is dirty

Clean the objective lens

Immersion oil was not used at high magnifications

Add immersion oil

Air bubbles are present in the immersion oil

Rotate the revolving nosepiece or add some more oil