Brother International HL-3400CN Service Manual - Page 316

CHAPTER

8

TROUBLESHOOTING

1-19

Mottle

Phenomenon

Variation

of

the

scanning

density

is

found

in

the

image

as

shown

in

print

sample

(19)

of

Page

8-46.

Main

Causes

(1)

The

transfer

unit

is

not

fixed

in

place.

(2)

Assembly

of

the

transfer

roller

is

inaccurate.

(3)

THV

output

of

the

high

-voltage

power

supply

unit

is

not

normal.

(4)

Failure

of

the

toner

cartridge.

(5)

Deformation

of

the

print

paper.

Countermeasures

(1)

Confirm

that

the

transfer

unit

is

firmly

locked

in

place.

(2)

Confirm

that

the

transfer

roller

is

properly

installed.

(3)

Replace

the

high

-voltage

power

supply

unit

with

a

new

one.

(See

Section

4.3.2

of

Chapter

7.)

(4)

Replace

the

toner

cartridge

with

a

new

one.

(5)

Replace

the

paper

with

new

paper

from

a

freshly

opened

ream.

1-20

Residual

Image

Phenomenon

Image

of

the

preceding

page

appears

on

every

other

page

as

shown

in

print

sample

(20)

of

Page

8-46.

Main

Causes

(1)

Cleaning

failure

due

to

lifting

of

the

cleaning

brush

of

the

drum

cleaner.

(2)

Contact

failure

of

the

drum

cleaner's

bias

pole.

(3)

Failure

of

the

high

-voltage

power

supply

unit.

Countermeasures

(1)

Check

if

the

drum

cleaner

is

properly

installed

or

not.

(2)

Replace

the

failed

high

-voltage

power

supply

unit

with

a

new

one.

(See

Section

4.3.2

of

Chapter

7.)

8-58

Brother International HL-3400CN Service Manual - Page 316

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