Bestscope Bs-2040bd User manual

BestScope

BestScope International

International

International Limited

Limited

Digital

Digital Biological

Biological

Biological Microscope

Microscope

BS-2040

BS-2040 BD

BD

User

User Manual

Manual

This manual is for digital biological microscope Model BS-2040B D . For the operation of

software part, please see the CD. To ensure the safety, obtain optimum performance and to

familiarize yourself fully with the use of this microscope, it is strongly recommended that you study

this manual thoroughly before operating the microscope.

BestScope

BestScope International

International

International Limited

Limited

1

CONTENTS

BS-2040BD

CONTENTS

CONTENTS ……………………………………………………………

……………………………………………………………

…………………………………………………………… 1

1

USER

USER NOTICES

NOTICES

NOTICES ……………………………………………………

……………………………………………………

…………………………………………………… 2

2

1

1 Components

Components

Components Name

Name

Name ………………………………………………

………………………………………………

……………………………………………… 3

3

2

2 Assembly

Assembly

Assembly …………………………………………………………

…………………………………………………………

………………………………………………………… 4

4

2.1

2.1 Assembly

Assembly

Assembly Diagram

Diagram

Diagram ………………………………………………

………………………………………………

2.2

2.2 Assembly

Assembly

Assembly Procedures

Procedures

Procedures ……………………………………………

……………………………………………

4

5

3

3 Adjustment

Adjustment

Adjustment ………………………………………………………

………………………………………………………

……………………………………………………… 9

9

3.1

3.1 Adjustment

Adjustment

Adjustment Set

Set

Set Diaphragm

Diaphragm

Diaphragm ………………………………………… 9

9

3.2

3.2 Adjustment

Adjustment

Adjustment Procedures

Procedures

Procedures ……………………………………………

11

4

4 Technical

Technical

Technical Specifications

Specifications

Specifications …………………………………………

…………………………………………

………………………………………… 14

14

5

5 Outfit

Outfit

Outfit ………………………………………………………………

………………………………………………………………

……………………………………………………………… 15

15

6

6 Trouble

Trouble

Trouble Shooting

Shooting

Shooting …………………………………………………

…………………………………………………

………………………………………………… 16

16

BestScope

BestScope International

International

International Limited

Limited

2

USER

USER NOTICE

NOTICE

BS-2040BD

1.

1. Safety

Safety

Safety Note

Note

1. Open the box carefully to avoid the accessories, like lens, dropping to ground or being damaged.

2. Do keep the instrument out of direct sunlight, high temperature or humidity, dusty and easy

shaking environment. Make sure the stage is flat, horizontal and firm enough.

3. When moving the microscope, carefully carry it with the handle and the base.

4. When running, the lamp house and nearby parts will be very hot. Please ensure there is enough

cooling room for them.

5. Make sure the instrument is earthed, to avoid lighting strike.

6. For safety, be sure the main switch is in “ O ” (off) state and cut off the power supply before

replacing the bulb or the fuse. If you replace the bulb during use or right after use, allow the lamp

bulb and the lamp house to cool completely before touching.

(Designated

(Designated bulb

bulb

bulb ：6V/20W

6V/20W

6V/20W Halogen

Halogen

Halogen Lamp)

Lamp)

7. Check the input voltage: be sure the input voltage which is signed in the back of the microscope is

consistent with the power supply voltage, or it will bring a serious damage to the instrument.

8. Always use the power cord provided by Novel.

II

II 、Maintenance

Maintenance

Maintenance and

and

and Care

Care

1. All the lenses have been adjusted properly; do not dismount them by yourself please.

2. The nosepiece and coarse and fine focusing parts are so delicate that it is forbidden to

disassemble them carelessly by yourself.

3. Keep the instrument clean, and do not pollute the optical element when wiping away the dust on

the instrument.

4. The contaminations on the prism, like fingerprints and oil smudges, could be gently wiped with

a piece of soft cloth or tissue paper, gauze which has been immersed in pure alcohol or ether.

(Note

(Note that

that

that the

the

the alcohol

alcohol

alcohol and

and

and ether

ether

ether are

are

are highly

highly

highly flammable,

flammable,

flammable, do

do

do keep

keep

keep them

them

them away

away

away from

from

from the

the

the fire

fire

fire or

or

potential

potential sources

sources

sources of

of

of electrical

electrical

electrical sparks,

sparks,

sparks, and

and

and use

use

use them

them

them in

in

in a

a

a drafty

drafty

drafty room

room

room as

as

as possible

possible

possible as

as

as you

you

can.)

5. Do not attempt to use organic solvents to clean the microscope components other than the glass

components. To clean them, use a lint-free, soft cloth slightly moistened with a diluted neutral

detergent.

6. When using, if the microscope is splashed by liquid, cut off the power at once, and wipe away

the splash.

7. Do not disassemble any parts of the microscope, as this will affect the function or reduce the

performance of the microscope.

8. Place the instrument in a cool, dry position. When not using the microscope, keep it covered

with a dust cover. Make sure the lamp socket is cool before covering the microscope.

BestScope

BestScope International

International

International Limited

Limited

3

1.Components

1.Components Name

Name

Name BS-2040BD

BS-2040BD

Eyepiece

Digital Binocular viewing head

Nosepiece

Objective

Main body

Stage Coarse and Fine Focus Knob

Illumination adjust knob

Condenser

Illumination

USB 2.0 Port

BestScope

BestScope International

International

International Limited

Limited

4

①

②

BS-2040BD

2

2 Assembly

Assembly

2-1

2-1 Assembly

Assembly

Assembly Diagram

Diagram

Hereby use the image of BS-2040B, except the head, other parts is the same as BS-2040BD. The

following figure shows the installation sequence of the components. The number in the figure shows the

assembly steps.

�

�Before

Before

Before installing,

installing,

installing, be

be

be sure

sure

sure every

every

every components

components

components is

is

is clean,

clean,

clean, do

do

do not

not

not score

score

score any

any

any parts

parts

parts or

or

or glass

glass

glass surface.

surface.

�

�Keep

Keep

Keep well

well

well with

with

with hexagon

hexagon

hexagon wrench

wrench

wrench provided.

provided.

provided. When

When

When changing

changing

changing the

the

the components,

components,

components, you

you

you will

will

will need

need

need it

it

again.

Main body

Objective

Binocular

viewing head10X Eyepiece

④

③

Power cord

BestScope

BestScope International

International

International Limited

Limited

5

BS-2040BD

2.2

2.2 Assembly

Assembly

Assembly Procedure

Procedure

Fig.1

Fig.3

Fig.2

2.2.1

2.2.1 Installing

Installing

Installing binocular

binocular

binocular viewing

viewing

viewing head

head

（

Fig.1-2

）

Insert the binocular viewing head into the

microscope head and turn it to a proper position,

then screw down the bolt to fix it.

2.2.2

2.2.2 Installing

Installing

Installing the

the

the eyepiece

eyepiece

（

Fig3-4

）

Insert the eyepiece into the eyepiece tube

until they are against each other, as shown

in Fig.4.

Fig.4

BestScope

BestScope International

International

International Limited

Limited

6

BS-2040BD

Fig.6

Fig.5

Fig.7

2.2.3

2.2.3 Installing

Installing

Installing the

the

the objective

objective

（

Fig.5-6

）

1. Adjusting the coarse focus knob until the

support device of the mechanical stage

reaches its low limit position.

2. Screw the lowest magnification objective

into the nosepiece from the left or the right

side, then revolve the nosepiece clockwise

and mount other objectives by the sequence

of low to high magnification

�Installing objective this way will make the

change of magnification to be easier during

using.

�

�Clean

Clean

Clean the

the

the objective

objective

objective regularly,

regularly,

regularly, for

for

for lens

lens

lens is

is

susceptible

susceptible to

to

to dust.

dust.

�

�When

When

When operating,

operating,

operating, use

use

use 10

10

10 ×magnification

magnification

objective

objective to

to

to search

search

search and

and

and focus

focus

focus specimen

specimen

firstly,

firstly, then

then

then replace

replace

replace with

with

with higher

higher

magnification

magnification objective

objective

objective if

if

if necessary.

necessary.

�

�When

When

When replacing

replacing

replacing the

the

the objective,

objective,

objective, slowly

slowly

turn

turn the

the

the nosepiece

nosepiece

nosepiece until

until

until you

you

you hear

hear

“

“ clicked

clicked

clicked ”

”

” ,

,

, that

that

that means

means

means the

the

the objective

objective

objective is

is

is in

in

place.

.2.4

.2.4 Mounting

Mounting

Mounting the

the

the filters

filters

（

Fig.7

）

1.

1. Place the required filter in front of the

condenser..

★the

the

the filter

filter

filter of

of

of the

the

the standard

standard

standard outfit

outfit

outfit is

is

is green

green

and

and baby

baby

baby blue.

blue.

BestScope

BestScope International

International

International Limited

Limited

7

BS-2040BD

2.2.5

2.2.5 Connecting

Connecting

Connecting the

the

the Power

Power

Power Cord

Cord

（Fig.8-10

Fig.8-10

Fig.8-10 ）

★The

The

The cable

cable

cable and

and

and cords

cords

cords are

are

are vulnerable

vulnerable

when

when bent

bent

bent or

or

or twisted,

twisted,

twisted, never

never

never subject

subject

subject the

the

power

power cord

cord

cord to

to

to excessive

excessive

excessive force.

force.

1. Set the main switch ①to “ O ” (off) state

before connecting the power cord.

2. Insert the plugs ②into the power jack ③of

the microscope safely.

3. Plug the power cord ④into the power

supply receptacle ⑤. Make sure the

connection is well.

★Do

Do

Do use

use

use the

the

the supplied

supplied

supplied power

power

power cord

cord

cord all

all

all the

the

time.

time. If

If

If lost

lost

lost or

or

or damaged,

damaged,

damaged, select

select

select the

the

the same

same

standard

standard cord,

cord,

cord, please.

please.

★A

A

A wide

wide

wide range

range

range of

of

of voltage

voltage

voltage ,like

,like

,like 100V

100V

100V ～

240V ,

240V , is

is

is acceptable

acceptable

acceptable for

for

for this

this

this microscope.

microscope.

2.2.6

2.2.6 Replacing

Replacing

Replacing the

the

the fuse

fuse

（

Fig.8-10

）

Do remember to set the main switch ①to

the state “ O ” (OFF) and unplug the power cord

before replacing the fuse. Rotate the fuse ⑥out

of the holder ⑦with the “ -- ” type screwdriver,

replace with a new fuse, then rotate it back to

the holder again.

Fig.8

Fig.9

Fig.10

BestScope

BestScope International

International

International Limited

Limited

8

Fig.11

BS-2040BD

Fig.12

2.2.7

2.2.7 Installing

Installing

Installing and

and

and Replacing

Replacing

Replacing the

the

the bulb

bulb

（

Fig.11-13

）

�Please use the specified halogen Lamp

6V20W.

1. Pull out the condenser holder as shown in

Fig.11.

2. Hold the bulb ①after you wrap it with

gauze or other protection materials, and

then insert its pin ②deeply into the jack

in the lamp holder.

3. During microscope using or soon after it is

turned off, the bulb, the lamp house and

nearby parts will be very hot and will

cause serious burns. Please turn the main

switch to “ O ” (off) and disconnect the

power plug, and make sure the bulb, the

lamp room and periphery are all cool.

Then, you can do your replacing.

�

�Insert

Insert

Insert the

the

the bulb

bulb

bulb gently.

gently.

gently. Squeezing

Squeezing

Squeezing too

too

too hard

hard

will

will damage

damage

damage the

the

the bulb.

bulb.

�

To

prevent

prevent reduced

reduced

reduced bulb

bulb

bulb life

life

life or

or

or cracking,

cracking,

do

do not

not

not touch

touch

touch the

the

the bulb

bulb

bulb with

with

with bare

bare

bare hands.

hands.

hands. If

If

fingerprints

fingerprints are

are

are accidentally

accidentally

accidentally left

left

left on

on

on the

the

bulb,

bulb, wipe

wipe

wipe the

the

the bulb

bulb

bulb with

with

with a

a

a soft

soft

soft cloth.

cloth.

4. Place the condenser holder back and press

fit.

Fig.13

BestScope

BestScope International

International

International Limited

Limited

9

3.

3. Adjustment

Adjustment

Adjustment and

and

and operation

operation

operation BS-2040BD

BS-2040BD

3.1

3.1 Adjustment

Adjustment

Adjustment set

set

set diagram

diagram

diagram （Fig.14-15

Fig.14-15

Fig.14-15 ）

Right Fine Focus Knob

Right Coarse Focus Knob

Tension Adjustment Collar

Main Switch

Portrait Adjustment Knob

Lateral Adjustment Knob

Brightness Adjustment Knob

Fig.14

BestScope

BestScope International

International

International Limited

Limited

10

BS-2040BD

Left Coarse Focus Knob

Interpupillar Distance Indicator

Fig.15

Clocking Set

Condenser Focusing Knob

Left Fine Focus Knob

Aperture Iris Diaphragm Collar

Indicator

BestScope

BestScope International

International

International Limited

Limited

11

BS-2040BD

3.2

3.2 Adjustment

Adjustment

Adjustment and

and

and Operation

Operation

3.2.1

3.2.1 Brightness

Brightness

Brightness Adjustment

Adjustment

（

Fig.16

）

1. Connect the power cord and set the main switch

to “ －” state (ON).

2. Turning the brightness adjustment knob

clockwise, the voltage raise, and the brightness

strengthen; whereas turning at the contra

direction, the voltage decline, and the brightness

weaken.

2.T �

�

�Using the microscope with low voltage in the

voltage range can prolong the service life of the

bulb.

3.3.2

3.3.2 Placing

Placing

Placing the

the

the Specimen

Specimen

Specimen （Fig.17

Fig.17

Fig.17 ）

1. Place the specimen ①in the center of the

mechanical stage and use the stage clips to clamp it.

2. Turn the portrait and lateral adjustment

knob ②of the mechanical ruler, move the specimen

to the required position.

�

�Be

Be

Be careful

careful

careful when

when

when changing

changing

changing the

the

the objective.

objective.

objective. If

If

If you

you

finish

finish the

the

the observation

observation

observation with

with

with the

the

the short

short

short working

working

distance

distance objective,

objective,

objective, and

and

and want

want

want to

to

to change

change

change another

another

another one,

one,

be

be careful

careful

careful of

of

of not

not

not letting

letting

letting the

the

the objective

objective

objective touch

touch

touch the

the

specimen.

3.3.3

3.3.3 Focusing

Focusing

Focusing the

the

the Specimen

Specimen

Specimen （Fig.18

Fig.18

Fig.18 ）

1. F ocus the specimen with 10X objective. To avoid

the objective touching the specimen during

focusing, you should raise the mechanical stage to

let the specimen close to the objective at first, then

slowly separate them to bring the specimen to

focus.

Fig.16

Fig.18

Fig.17

BestScope

BestScope International

International

International Limited

Limited

12

BS-2040BD

Turn the coarse focus knob ①conversely to

lower the specimen and search images in the

10 × ocular simultaneously, and then use the fine

knob ②to focus. After that, you can replace with

other magnification objectives safely, and focus

without the risk of damaging the specimen.

�

To

make

make the

the

the observation

observation

observation more

more

more convenient,

convenient,

convenient, you

you

can

can use

use

use the

the

the locking

locking

locking set

set

set ③to

to

to fix

fix

fix the

the

the stage

stage

stage in

in

in a

a

vertical

vertical direction.

direction.

3.3.4

3.3.4 Condenser

Condenser

Condenser Adjustment

Adjustment

Adjustment （Fig.20

Fig.20

Fig.20 ）

Turn the condenser focus knob to move the

condenser up and down. Raise the condenser when

using the high magnification objective, and descend it

when using the low magnification one.

�

�The

The

The condenser

condenser

condenser and

and

and the

the

the objective

objective

objective are

are

are coaxial.

coaxial.

coaxial. It

It

has

has been

been

been adjusted

adjusted

adjusted before

before

before leaving

leaving

leaving factory,

factory,

factory, so

so

so the

the

user

user needn

needn

needn ’

’

’ t

t

t to

to

to adjust

adjust

adjust them

them

them by

by

by self

self

�

�The

The

The highest

highest

highest position

position

position of

of

of the

the

the condenser

condenser

condenser has

has

has been

been

adjusted

adjusted too.

too.

too. It

It

It also

also

also needn

needn

needn ’

’

’ t

t

t any

any

any user

user

’

s

operation

operation .

3.3.5

3.3.5 Aperture

Aperture

Aperture Iris

Iris

Iris Diaphragm

Diaphragm

Diaphragm Adjustment

Adjustment

（

Fig.20

）

Turn the aperture iris diaphragm collar ①to

adjust the aperture iris diaphragm.

�

�The

The

The aperture

aperture

aperture iris

iris

iris diaphragm

diaphragm

diaphragm is

is

is designed

designed

designed for

for

the

the adjustment

adjustment

adjustment of

of

of the

the

the numerical

numerical

numerical aperture

aperture

aperture ,not

not

not for

for

the

the brightness.

brightness.

Generally,

Generally, setting

setting

setting the

the

the aperture

aperture

aperture iris

iris

iris diaphragm

diaphragm

to

to 70-

70-

70- 80%

80%

80% of

of

of the

the

the N.A.

N.A.

N.A. of

of

of the

the

the objective

objective

objective in

in

in use

use

use will

will

provide

provide an

an

an image

image

image with

with

with good

good

good contrast.

contrast.

contrast. If

If

If you

you

you want

want

to

to observe

observe

observe the

the

the image

image

image of

of

of the

the

the aperture

aperture

aperture iris

iris

diaphragm,

diaphragm, remove

remove

remove one

one

one eyepiece

eyepiece

eyepiece and

and

and look

look

look through

through

the

the tube.

tube.

You

will

will see

see

see a

a

a dark

dark

dark circle

circle

circle encroaching

encroaching

encroaching on

on

the

the bottom

bottom

bottom of

of

of the

the

the tube.

tube.

Fig.19

Fig.20

BestScope

BestScope International

International

International Limited

Limited

13

BS-2040BD

3.3.6

3.3.6 Adjusting

Adjusting

Adjusting the

the

the Interpupillary

Interpupillary

Interpupillary Distance

Distance

（

Fig.21

）

The interpupillary distance range:

55mm ～75mm 。

While looking through the eyepieces, move both

eyepieces until the left and right fields of view

coincide completely.

3.3.7

3.3.7 Adjusting

Adjusting

Adjusting the

the

the Diopter

Diopter

（

Fig.22

）

1. Turn the eyepiece ①to adjust the diopter while

looking through it.

★

The

The diopter

diopter

diopter range

range

range of

of

of the

the

the eyepiece

eyepiece

eyepiece is

is

is ±

±

± 5

5

diopter.The

diopter.The number

number

number aligned

aligned

aligned to

to

to the

the

the line

line

line on

on

on the

the

viewing

viewing head

head

head is

is

is the

the

the diopter

diopter

diopter in

in

in use.

use.

3.3.8

3.3.8 Adjusting

Adjusting

Adjusting the

the

the tension

tension

tension adjustment

adjustment

collar

collar （Fig.23

Fig.23

Fig.23 ）

Turn the tension adjustment collar ①with your

fingers .When the collar is turned in the

direction of the arrow, tension of the coarse

adjustment knob ②increases. Turning the collar

in the opposite direction decreases the tension.

If the nosepiece descends on its own or if the

specimen gets out of focus quickly even when it

is brought into focus using the fine adjustment

knob ③, it means the tension of the coarse

adjustment knob is too low. Turn the collar in

the direction of the arrow to increase the tension

Fig.22

Fig.21

Fig.23

BestScope

BestScope International

International

International Limited

Limited

14

4

4．Technical

Technical

Technical Specifications

Specifications

Specifications BS-2040BD

BS-2040BD

1)

1) 、Main

Main

Main Specifications

Specifications

Optical System Infinite optical system

Viewing Head Siedentopf Binocular Head, 30 ° Inclined,Interpupilary Distance 48-75 mm

Eyepiece Wide Field Eyepiece WF 10X/18

Nosepiece Quadruple Nosepiece

Objective Infinitive Semi-plan Objectives 4 × , 10 × , 40 × , 100 ×

Focusing Coaxial Coarse and Fine Adjustment, Moving Range20mm,Fine Division 0.002mm

Condenser Abbe Condenser , NA=1.25

Stage Double Layers Mechanical Stage 140mm × 140mm ，Moving Range 75 × 50mm

Illumination 6V20W Halogen Lamp

2)

2) 、Eyepiece

Eyepiece

Eyepiece and

and

and objectives

objectives

1. objective

Magnification Numerical Aperture Focal Length （mm ）Working Length （mm ）Objective

4 × 0.10 45.3 17 dry

10 × 0.25 17.96 6 dry

40 × 0.65 4.5 0.37 dry

100 × 1.25 1.81 0.13 oil

2. Eyepiece

Eyepiece Magnification Focal Length （mm ）Field of View （mm ）

Wide field plan eyepiece 10 × 25 φ 22

BestScope

BestScope International

International

International Limited

Limited

15

5

5．Outfit

Outfit

Outfit BS-2040BD

BS-2040BD

Main Body

Main Standard 〇

Double Layers Mechanical Stage 〇

Condenser Holder 〇

Viewing Head Siedentopf Binocular Head 〇

Condenser Abbe Condenser, NA=1.25 〇

Nosepiece Quadruple 〇

Illumination

6V20W Halogen Lamp 〇

Spare Bulb 〇

Eyepiece 10 × Wide Field Plan Eyepiece 〇

Objective

Infinite Semi-Plan Objective 4 × 〇

Infinite Semi-Plan Objective 10 × 〇

Infinite Semi-Plan Objective 40 × 〇

Infinite Semi-Plan Objective 100 × （Oil ）〇

Condenser

Bright Field Condenser with Adjustable Iris

Diaphragm

〇

Filter Baby Blue, Green 〇

BestScope

BestScope International

International

International Limited

Limited

16

6

6．Troubleshooting

Troubleshooting

Troubleshooting Guide

Guide

Guide BS-2040BD

BS-2040BD

1. Optical

Optical

Optical System

System

TROUBLE

TROUBLE CAUSE

CAUSE

CAUSE SOLUTION

SOLUTION

1. The edge of the field

of view is dark or the

brightness is not

uniform

The nosepiece is not in the located

position (objective and light path not

coaxial)

Locate the nosepiece

properly where it clicks

The surface of the lamp becomes black Change a new lamp bulb

A lens (the objective, condenser, eyepiece

or collector) is dirty.

Clean it thoroughly

2. Dirt or dust is visible

in the field of view

Dirt/dust on the specimen

Replace with a clean

specimen

Dirt/dust on the eyepieces Clean them

3. Visibility is poor

Image is not sharp;

Contrast is poor;

Details are indistinct

Specimen is not covered Add cover glass on it

The thickness of the cover glass is not

suitable

Use standard cover glass

with thickness of 0.17mm

Specimen is placed reversely Turn it over

Dry objective has oil on it. (especially for

40X objectives)

Wipe the oil

A lens (the objective, condenser, eyepiece

or collector) is dirty.

Clean it

Immersion oil is not used with the 100x

objective

Use specified oil

Air bubbles existed in the immersion oil Eliminate the bubble

The aperture iris diaphragm is stopped

down too far

Adjust the aperture iris

diaphragm properly

Dirt or dust on the eyepiece Clean it

4. One side of image is

blurred

Condenser is not properly centered

Center the condenser with

the centering screw

The nosepiece is not properly engaged

Engage the nosepiece

properly

The specimen is not clamped Clamp it with stage clips

5. The image is

yellowish

The blue filter is not used Use the blue filter

6. The brightness is not

enough

The aperture iris diaphragm is too small Adjust it properly

The condenser is too low Adjust it properly

A lens (the objective, condenser, eyepiece

or collector) is dirty.

Clean it

BestScope

BestScope International

International

International Limited

Limited

17

BS-2040BD

2.

2. Mechanical

Mechanical

Mechanical System

System

TROUBLE

TROUBLE CAUSE

CAUSE

CAUSE SOLUTION

SOLUTION

1. Field of view of

one eye does not

match that of the

other

Interpupillary distance is incorrect Adjust interpupillary distance

2. Observation is

tiring

The diopter is not proper Adjust the diopter properly

The brightness of the illumination is not

proper for eyes

Adjust the lamp voltage

3.

3. Electrical

Electrical

Electrical System

System

TROUBLE

TROUBLE CAUSE

CAUSE

CAUSE SOLUTION

SOLUTION

1. The bulb cannot

light

No power supply Check the power cord connection

The pin of the bulb doesn ’ t insert

properly

Insert the pin deeply

The bulb broken Replace with a new one

2. The bulb burns out

suddenly

The bulb is not the specified one;

The voltage is too high

Use the specified bulb;

lower the voltage

3. the illumination is

not bright enough

the voltage is too low Raise the voltage

4. Image flicks

The bulb is about to burn out Replace with a new one

The bulb is not inserted deeply Check its connection

BestScope BS-2040BD User manual

Popular Microscope manuals by other brands