Brother T-8420A, T-8421A, T-8422A, T-8720A, T-8722A Service Manual

T-8420A, 8421A,

8422A

service

manual

T-8720A,

Please

TWIN

NEEDLE

LOCK

8722A

read

this manual before making

STITCHER

any

adjustments.

brother.

This service manual is intended for T-8420A, 8421A,8422A, 8720A, 8722A; be

manual.

Carefully

maintenance.

Asa resultof research and improvements regarding this product, some details ofthismanual may notbe the same as those for

the

Ifyou have

read the

product you

any

"SAFETY

purchased.

questions regarding this product, please contact a Brother dealer.

INSTRUCTIONS"

below

and the

whole

ofthismanualto understandthis

suretoread

the

instruction manual before this

product

beforeyou start

SAFETY

1.

Safety

This service manual and the indicationsand symbols that are used on the machine itself are provided in order to ensure safe

operation of this machine and to prevent accidents and injuryto yourselfor other people.

Indications

A A

Symbols

indications

C

AUIION

0

NO

O

iTirNM

This

indicates

(For example,

This

and

their

meanings

PR

Clx

symbol

the

instructions

and surroundings.

(^)

indicates

natureofthe

the

symbol at left

symbol()indicates

INSTRUCTIONS

which

cause

that

means

foilow

certainly

follow

injury

when

that

mustbetaken.

"beware of injury".)

that

will

almost

could

something

caution

something

this

term

resultindeathorsevere

this

you

indicate

term

indicate

using

the

shouldbecareful

must

not

situations

machineorphysical

do.

injury.

of.

The

where

failuretofollow

where

failuretofollow

damagetoequipment

picture

inside

the

triangle

Q

This

symbol

natureofthe

(For example,

(^)

thing

that

the

symbol at left

indicates

mustbedone.

something

means

that

you

must

"you must make

do.

The

picture

the

ground connection".)

inside

the

circle

indicates

the

T-8400A,

8700A

2.

A

Notes

on

Wait

at least5

opening

safety

minutes

after

thefaceplateofthe

turning

control

off

thepower

box.

Touching

A

DANGER

switch

areas where

CAUTION

and

disconnecting

the

power

high

voltages'are presentcan

cord

from

the

result

wall

outlet

insevere

before

injury.

Environmental

Use the sewing machine in an

from

sources high-frequency welders. Sources problems with correct operation.

Anyfluctuations inthe power supply voltage should

be within ±10% of

Voltage fluctuations cause

problems with correct operation.

The power supply capacity should be greater than the requirements for

o

electrical

Insufficient

problems with correct operation. The

ambient temperature should be within

range of

Temperatures which

may

cause

Machine installation

qualified technician.

0

Contact your Brother electrician for

be

done.

The sewing machine weighs approximately 50 kg.

The

installation shouldbecarried out by two or

more people.

Do not complete. The machine may

0

depressed Turn off the power switch before inserting or

removing the plug, otherwise

box

could

Be

suretoconnect

connection is not

O

receiving a

with

correct

of strong electrical noise

of strong electrical noise may

the

rated voltage for

vyhich

consumption.

power

5®CtoSS'C

problems with correct operation.

connent

by mistake, which could result in injury.

result.

serious

operation

supply capacity

during

are

should

any

electrical work that may

the

power cord until installation is

the

secure,

electric shock, and problems

may

area

are

greaterthan this may

the

sewing machine's

use.

lower or higher than this

onlybecarried

dealer

operate

damage

ground. If

you run a high risk of

also

occur.

which is free

such

as

cause

the

machine.

may

cause

the

Installation

out

by a

or a qualified

need

ifthe treadle is

to the control

the

ground

requirements

The relative

45% to 85% during use, and no

should

Excessively dry or humid environments and dew

formation may

operation.

Avoid exposure to direct sunlight during use.

o

to

Exposure to direct sunlight may

correct operation.

In

and disconnect the power cord from

Lightning may

operation.

All

from any moving parts. Furthermore, do not

excessively bend the cords or

with staples, othenwise there is

0

electric

If using a work table which

should be

move.

Use

tilting

A

only one hand is used,

head

may

Be

handling the lubricating oil

0

do not

inflammation

Furthermore, do not drink under

vomiting

Keep

humidity

occurinany

the

eventofan

cords

shouldbesecuredatleast25mm

shocks

securedinsuch

both

hands

it back or retuming it to its original position. If

may

cause

get

caught.

suretowear

get

into your

can

any

circumstances,

and

diarrhea.

the oil

outofthe

should be within the range of

dew

devices.

cause

electrical

cause

could

to

your

protective

result.

problems with correct

cause

storm,

tum

the

problems with correct

secure

them

the

danger

occur.

has

casters,

a waysothat

hold

the

machine

the

weight of

hand

to slip,

goggles

and

eyes

or onto your skin, otherwise

the

reach

of children.

and

grease,sothat they

oil or

eat

as

they

formation

problems with

off

the

wall outlet.

too

thatfire or

the

they

head

the

your hand

gloves

the

can

power

away

firmly

casters

cannot

when

machine

when

grease

cause

T-8400A,

8700A

A

CAUTION

Sewing

This sewing machine should only be

operators

0

In

safe

The sewing machine should not be

0

applications other than sewing.

Be

machine.

O

Ifgoggles

needle your

Tum off The

A

by

When using a clutch motor,

turning

result of

who

have

received

use

beforehand.

sure

to wear protective goggles when using the

are

breaks,

eyes

and

the

machine may

mistake,

which could

even

the

motor's Inertia. Walt until

not wom,

partsofthe

Injury

power switchatthe

after

there

may

operateIfthe

result

the

power

fullybefore starting work.

•

When

•

When

• When not using

the

machine

Turn off

cleaning.

A

depressed When

using a clutch motor, turning resultof

fullybefore starting work.

Use

tilting It

A

only head

may

even

the

both

back

one

may

get

threading replacing

the

The

by mistake, which could result In injury.

hands

handIsused,

cause

caught.

the

needle

the

bobbin

the

machine and when leaving

unattended

power switch before carrying out

machine

after

motor's Inertia. Walt until

or retuming It to Its original position. If

the

to

your

may

power

hold

the

hand

the

necessary

used

Is the

danger

broken

result.

the

needle

following times.

treadle Is

In Injury.

the

motor

Is switched offasa

the

and

needle

operateIfthe

the

motor will

Is switched offasa

the

machine

weightofthe

to slip,

and

used

by

training

for any

that Ifa

may

enter

depressed

will

keep

motor

stops

Cleaning

treadle Is

keep

motor

stops

head

when

machine

your

hand

If using a work

o

shouldbesecuredInsuchawaysothat

move.

Attach all

machine.

A

devices

Do not touch objects

A

may

machine.

Use

tilting It

A

only

head

may Ifanerror

smells

O

switch. Then

qualified

If

nearest

O

Be

handling

0

do not

Inflammation

Furthermore,donot under

vomiting

Keep

attached. Injury may result.

against

result in

both

back

one

may

get

are

the

machine

Brother

suretowear

get

any

the

table

which

safety

devices

If

the

machine

anyofthe

the

machine while sewing,asthis

personal

hands

to

hold

or retuming Itto its original position. If

handisused,

cause

your hand to slip,

caught.

occursInmachine,orIf

noticed, immediately

contact

technician.

the

lubricating oil

Into

can

circumstances,

and

diarrhea.

oil

outofthe

develops

dealer

protective

your

eyes

result.

your

or a qualified technician.

drink

reach

has

casters,

before using

Is

used

moving

injury or

the

machine

the

weightofthe

abnormal

nearest

a problem, contact your

goggles

and

grease,sothat they

or onto

your

the

oiloreat

as

of children.

the

casters

they

the

sewing

without

partsorpress

damage

head

machine

and

your hand

noises

tum

off the power

Brother

dealer

and

gloves

skin, otherwise

the

they

can

grease

cannot

to the

cause

these

any

when

or

or a

when

Disassembly,

Inspection of

0 O

A

out

carried

Ask

your

carry

out

electrical Tum

off

the cord from othenA/lse depressed When

using a clutch motor,

tuming

resultof

fully before starting work.

Turn off

removing

box

•

When

maintenance

•

When

rotary hook

could

even

the

Maintenance

assembly,

the

sewing

by a qualified technician.

Brother

system.

the

carrying out Inspection, adjustment and

replacing

the

dealer

any

maintenance

power

switch

the

wall outletatthe

machine

by mistake, which could result In Injury.

after

motor's

and

the

power

plug,

result.

may

the

power

Inertia.

consumable

knife

switch

othenvlse

maintenance

machine

or a qualified electrician to

and

operateIfthe

Walt

should only be

and

Inspection of

disconnect

the Is switched offasa

until

parts

before

damagetothe

the

power

following times,

treadle

motor will

the

motor

suchasthe

Inserting or

control

keep

stops

T-8400A,

and

the

and

Is

inspection

Use

both

hands

It

back

or retuming Itto Its original position. Ifonly handIsused, cause

your

hand

caught.

If

the

power

switch

out

some

adjustment,

all

safety

precautions.

Be

careful not to

amount

A

rotary the otherwise

Use

O

Brother.

If absolutely

O

positions

using

Any problems In

0

unauthorized

_covered_bjrttiewamantj^^^

8700A

check

hookorthe

amount

only

the

any

safety

the

of oil supplied to

Injury

proper

sure

and

check

machine.

modificationstothe

to hold

the

weight of to slip,

needstobe

touch

sheet

against

feed

may

replacement

devices

to re-Install

that

machine

the

machine

and

be extremely careful to

your fingers or

moving

mechanism

result.

have

they

operation which resultfrom

head

the

machine

your

hand

leftonwhen

the

parts

when

the

rotary hook,

partsasspecified by

been

removed, be

them

to their original

operate

correctly before

machine

when

tilting

one

head

may

get

carrying

observe

lubrication

suchasthe

checking

will

not

be

III

S.Warning

labels

The following warning labels

Please

difficultto read,

<T-8420A,

followthe instructions on

please

contact your

8720A>

/-

—

1

A ^

A

CAUTION

Movingpartsmay

Operate

Turn

threading, changing bobbin

and

Safety

with safety devices.

off

main

needle, cleaning

devices:

(A) Finger guard (B)

Thread

(C) Beit cover

switch

take-up

cause

cover

appear

injury.

before

etc.

on the sewing machine.

the

labels at all times when using the machine. Ifthe labels

nearest

Brother dealer.

Be

sure

to connect

connection is not secure, you run a high risk of receiving a serious electric shock, and problems with

correct operation may

Direction of operation

the

also

have

been removed or are

ground. If

occur.

the

ground

0

Oil

2955M

pan

2954M

IV

T-8400A,

8700A

2956M

<T-8421A,

f -

1

1A

Hazardous voltage

will

cause

Turn

and

before opening this

cover.

8422A,

A

DANGER

injury.

off

main

switch

wait

Smlnutes

8722A>

A n P

AGEFAHR

Hoclispannung

verletzungsgei^hr!

BItte

schalten

sle

hauptschalter

warten

bevorsiediese

abdeckung

den

aus

sie5minuten,

dffnen.

^ A )b

ADANGER

Unvoltage non adapte

provoque

Eteindre rinterrupteur et

imd

attendre5minutes

d'ouvrir le capoL

des

blessures.

avant

Pa

APELIGRO

Un voltaje Inadecuado

puede

provocar las

herida8.Apagar el

Interrupter principal y

esperar

5 minutos

esta

antes

cublerta.

de

abrir

—^

1

A ^

A

CAUTION

Moving

parts

may

cause

injury.

Operate with safety devices.

Tum

off

main

switch

before

threading, and

changing

bobbin

needle, cleaning etc.

LO

^

secure,

and

Direction of

connect

you

runahigh

problems with correct operation may

operation

Oil

pan

the

ground.Ifthe

riskofreceivingaserious

2867M

ground

also

connection

electric

occur.

Is not

shock,

Safety

devices:

(A)

Finger

(B) Thread

guard

take-up

cover

Control

box

2083M

T-8400A,

8700A

2868M

1.

MACHINE

2.

NOTES

3.

LUBRICATION

Needle

3-1.

rocking mechanism

(minimum lubricationtype) 6

3-2.

Needle

rocking mechanism and

(semi dry type) 7

3-3.

Feed

regulator bushing (both lubrication type) 8

3-4. Rotary hook

minimum lubrication type) 9

3-5.

Feed

lubrication type) 9

4.

ADJUSTMENT

4-1.

Safety

specifications: T-8421A, 8422A, 8722A) 10

4-2.

Thread

spring 11 Thread

4-3.

SPECIFICATIONS

ON

HANDLING

SYSTEM

bar

and

thread

take-up,

and

presser

bar

and

thread take-up,

presser

and

feed rocker

semi

dry

and

minimum

base

(both

semi

bar

(both semi dry

switch position (DD motor

take-up

amount

spring tension 12

and

for

thread

needle

bar

needle

bar bushing

shaft

dry

and

minimum

take-up

CONTENTS

bar

bushing

bar

10

1

5

6

4-10.

Unifying

reverse

stitch lengths for normal feed and

feed

4-11. Rotary hook

4-12.

Clearance

bases

between

23

position 24

rotary hook

and

needle

plate 26

4-13.

4-14.

Clearance

opener

Presser

between

rotary hook

and

27

foot height 27

4-15. Installing thefeed dog 28 4-16. 4-17. 4-18.

4-19.

4-20.

4-21. Replacing the fixed knife

Feed

dog position 28

Feed

dog height 29

Feed

dog angle 30

Tension

Thread

thread

release

trimming timing (Models with

trimmer: T-8422A, 8722A) 32

and

movable knife

31

(Modelswiththread trimmer

T-8422A8722A) 34

4-22. Movable knife position (Models with thread

trimmer. T-8422A, 8722A)

35

4-23. Plate spring (Models with thread trimmer: ^

T-8422A, 8722A) 37

4-4.

Thread

4-5.

Upper

(Under-table motor specifications:

T-8420A, 8720A) 14

4-6.

Upper

(DD

T-8421A, 8422A, 8722A)

4-7.

Needle Needle

4-8.

4-9. Quick

T-8421A, 8422A, 8722A) 22

take-up

shaft

motor

drop and

reverse

amount

and

lower

shaft

timing

and

lower

shaft

timing

specifications:

fonward-back position 17

rotary hook timing

device (DD motorspecifications:

13

15

20

T-8400A,

4-24. Tension

release

trimmer. T-8422A, 8722A) 38

4-25.

Thread

wiper (Models with

T-8422A, 8722A) 39

4-26. Adjusting the needle up 4-27. Adjusting the treadle 41

4-28. Adjusting

4-29.

8700A

amount

Adjusting

(minute

the

lifting

wire (Modelswith thread

thread

stop

position 41

rotary hook lubrication

presser

foot floating

amount)

trimmer

42

amount

43

5.

APPLYING

5-1.

When

the

GREASE

indicator

illuminates

44

(T-8420A, 8720A: Semi dry type) 44

11.

CONTROL

(T-8421A, 8422A,

11-1. Removing

BOX

and

AND

8722A)

installing

MOTOR

the

controi box 76

76

5-2. When "GREASEUP"

8422A, 8722A:

6.

GREASE

LUBRICATION

AND

7.

SWITCHING

TO

8.

REPLACING

APPLICATION

REPLACING

LOWER

WHEN

FROM

FEED

GAUGE

appears

Semi

dry specifications) 47

DISASSEMBLING

PARTS

NEEDLE

(T-8421A,

AND

PARTS

FEED

(CHANGING THE NEEDLE WIDTH)... 55

9.

FUNCTION

SETTINGS

(T-8421A, 8422A, 8722A) 57

9-1. Maximum sewing

sewing

9-2. Using

9-3. Setting

9-4. Setting functions

9-5.

Function

9-6. Clearing

10.

CONTROL

speed

the

LOCK key 58

the

List

saved

speed

setting

DiP

switches

data

SYSTEM

and

start backtack

methods

(Initialization) 74

(T-8421A, 8422A, 8722A) 75

50

53

57

58

59

60

and

11-2. Control box

11

-3.

Control

11-4. Checking 11-5. Checking

12.

TREADLE

circuit

motor rating piate 77

board

the

motor

and

power

the

soienoids

UNIT

ASSEMBLY

supply

(T-8421A, 8422A, 8722A) 83

12-1.

Types

12-2.

Standard

12-3. Setting method for

strokes

13.

STANDING

(T-8421A, 8422A,

13-1. Installing

13-2.

Connectors

14.

TROUBLESHOOTING

14-1.

Sewing

14-2. Error

(T-8421A. 8422A, 8722A) 101

setting

OPERATION

the

code

displays

values

standard

depression

PEDAL

8722A)

foot plug 87

79

81 82

83 84

85

87

88

89

'P8400A,

8700A

1.

MACHINE

1.

<

Model

SPECIFICATIONS

MACHINE

plate

Indications

SPECIFICATIONS

>

BROTHER

•

T-8421A-T03

T T

INDUSTRIES,

LTD.

•

TTT

J

A

B

C

—______

Rotary

"

Thread

Quick

Thread

D

Lubrication

E

<

Listofmodels

standard

With

thread

Thread

Use

hook

trimmer

hook

trimmer

reverse

wiper

-

tvpe

and

specifications

A B

4

Standard

0 1

0

-

Minimum

F

For

foundation

hook

-

0

lubrication

>

Motor

DD

motor

T-8422A

For

medium-

ODE

4

O

3

light-weight

weight

Lubrication

(Dryr Semi

dry

-030

Minimum

-OOO

and

materials

lubrication

type

7

Large

hook

2

O

T

O

—

3

Semi

dry

5

For heavy-weight materials

Use

(-003)

-003. (-005)

-003.

-005

Without

thread

trimmer

Large hook

I

Thread

With

thread

Without

( )

Itis available from local

thread

types

trimmer

are

not included in

dealers

DD

motor

T-8421A

Under-table

T-8420A

DD

motor

T-8422A

Under-table T-8420A

the

specification lineup.

by special

order

motor

Motor

motor

or by installing optional parts.

T-8400A,

8700A

(Dry)*

Semi

-030

Minimum

-OOO

(Dry)*

Semi

-030

Minimum

-OOO

Lubrication

Minimum

-OOO

Minimum

-OOO

dry

lubrication

type

lubrication

(-003.-OOF)

-OOF.-003. (-005)

(-00F).-003.-005

(-003.-OOF)

-OOF.-003. (-005)

-OOF.-003.-005

Use

-003.

-DOS

-003.

-005

<

Drive

Installation position

Type

Control

<

Gauge

motor

circuit

part

>

Built

AC

Microprocessor

widths

DD

motor

into

servo

machine

motor

head

(4-oole,

550W)

(compatibility with

bed

Installed

(obtained

Clutch

and

Under-table

under

locally)

motor,

rotary

etc.

hook

Refer to the parts book forthe availabilityofgauge parts for various specifications.

T-8420A.

T-8422A T-8720A T-8722A

Model

8421A

Standard

1.6-38.1

bed

mm

Special

Max.77mm Max.45mm

Max.68mm Max.45mm

table

-

motor

order

1.

MACHINE

base)

SPECIFICATIONS

>

T-8400A,

8700A

1.

MACHINE

<

Specifications

SPECIFICATIONS

>

T-8420A

T-8421A

Use

Max.

Start

backtacking

End

Max.

Presser

Feed

Thread

Needle

Presser

Rotary

Needle

(Standard

sewing

backtacking

stitch

foot

dog

height

take-up

bar

foot

hook

DP

(Standard/Organ)

Feed

mechanism

Arm

pocket

Weight

speed

length

height

stroke

pressure

x 5

width

speed

stroke

hook,

hook.

(Dry)

Semi

Minimum

lubrication

and

Lifting

Knee

T-8420A

T-8421A

Without

dry

continuous

lever

lifter

thread

trimmer,

-nnF

For

foundation

7.5-58.5

#11

(#9-#14)

Under-table

DP

motor)

3,000

4,000

51.9

Thread

take-up

N

Horizontal rotary

Needle

motor)

-nn3

For

light-weight

medium-

rpm

250

- 1,800 rpm (T-8421A only)

1,000

rpm

4

mm

lever

Standard

feed/Lower

120

weight

materials

3,000

rpm

(T-8421A

7

mm

13

mm

1

mm

No.3

33.4

mm

hook

#14

(#11-#16)

feed

x264

42.5

46.5

hook

kg

and

only)

Thread

10-78N

(vertical axis)

(Canbeswitched)

mm

-nn5

For

heavy-weight

materials

3,000

5

56.8

take-up

No.5

#22

(#14-#22)

-

rpm

mm

lever

T-8422A

Use

Max.

Start

(Standard

sewing

backtacking and continuous

backtacking End

backtacking

Max.

stitch

Presser

Feed

Thread

Needle

Presser

Rotary

Needle

(Standard/Organ)

Feed

Arm Weight

foot height

dog

height

take-up

bar

foot

hook

DP

mechanism

pocket

speed

length

stroke

pressure

x 5

width

speed

stroke

hook.

(Dry)

Semi

Minimum lubrication

Lifting

Knee

With

dry

lever

lifter

thread

trimmer,

medium-

DD

motor)

-nn3

For light-weight

weight

3,000

4,000

materials

rpm

and

3,000

rpm

250-1,800

1,000

rpm

4 mm 1 5

7

mm

13

mm

1

mm

51.9

mm

(#11

Thread

Horizontal rotary

#14

-#16)

Needle

feed/Lower

take-up

33.4

10-78

Standard

120x264

49.5

lever

mm

hook

feed

kg

For

heavy-weight materials

3,000

rpm

No.3

N

(vertical axis)

(#14-#22)

(Canbeswitched)

mm

-nn5

-

rpm

mm

#22

T-8400A,

8700A

1.

MACHINE

SPECIFICATIONS

T-8720A (Large

T-8722A

Use

Max.

speed

Start backtacking

backtacking

End Max.

Presser

height

Feed

Thread

Needle

Presser

Rotary

Needle

(Standard/Organ)

Feed

Arm

Weight

(Large

sewing

speed

backtacking

stitch

length

dog

height

take-up

bar

stroke

foot

pressure

hook

DP

mechanism

pocket

width

foot

x 5

hook

speed

stroke

• Without

• With

Minimum

lubrication

and

Lifting

Knee

lifter

T-8720A

T-8722A

thread

continuous

lever

thread

trimmer, DP

trimmer, Under-table motor)

motor)

-nns

For light-weight

medium-

weight

(#11

#14

and

materials

250-1,800

1,000

Thread

Horizontal rotary

-#16)

Needle

feed/Lower

3,000 rpm

rpm (T-8722A only)

rpm(T-8722A

7

mm

7

mm

13

mm

1

mm

62.4

mm

take-up

10-78

Large

120X264

33.4

42.5

49.5

lever

mm

N

hook

(vertical axis)

hook

feed

(Canbeswitched)

mm

kg

-nns

For

heavy-weight materials

only)

No.6

#22

(#14-#22)

T-8400A,

8700A

2.

NOTES

ON

HANDLING

NOTES

ON

HANDLING

About

the

• Do not

such

machine

set

as

set-up

up this sewing machine

televisions,

location

radios

or

near

other

cordless

otherwise such equipment may be affected by electronic

interference from

the

sewing

machine.

• The sewing machine should be plugged directly intoan AC

wall outlet. Operation problems may result if extension

cords

are

used.

Carrying

the

•

The

as

showninthe

<T-8420A,

Make

<T-8421A,

Hold

does

machine

machine should be carried by the arm by two

illustration.

8720A>

sure

that

the

not

8422A,

motor

rotate.

machine

8722A>

cover

(A) by hand alsosothat

pulley

does

equipment

telephones,

people

not

tum.

the

pulley

<T.8420A.

<T-8421A.8422A.

8720A>

8722A

2086M

2959M

>

Tilting

back

• Hold

move,

the

Returning

1.

Clear

holes.

2. While holding

retum

right

the

section

and

machine

the

away

the

hand.

machine

(B) with

then

push

head.

machine

any

tools,

the

machine

head

your

footsothat

the

arm

headtothe

etc.

which

face

plate

headtothe

the

table

with both

with

upright position with

hands

upright

maybenear

your

left

hand,

position

does

to tilt

the

o

2870M

not

back

2871M

table

gently

your

2872M

T-8400A,

8700A

3.

LUBRICATION

SYSTEM

3.

LUBRICATION

SYSTEM

3-1.

Thread

mechanism

Needle

presser

take-up

bar

and

thread

bushing

take-up,

(minimum

Oil

terminal

needle

lubrication

Oil

tank

bar

rocking

type)

mechanism

(2) Two

and

[G]Lubrication points requiring

(1)Wick

(2)

Felt

Presser

bar

bush

r

grease

[Q]

Folded

(2)

over

twice

po

go

(1) Two

Oil recovery•

from

jaw

-[Gl

Needle

bearing

D I I

-Jl

I-

[Q]

[01-

3007M

:i

rw

n

L'

y

T-8400A,

8700A

3008M

3.

LUBRICATION

SYSTEM

3-2.

Needle

presser

[G] Lubrication points requiring

i:|>

(1)to (7)requiregrease application.

(8) Wick

bar

(2)ci>|

and

thread

bushing

grease

take-up,

(semi

dry

.btd

(8) [Grease applied]

[TWn

o

C<;3(7)

needle

type)

[G]

1^:'

„

If

bar

I r

1 L

rocking

[0]

mechanism

and

Thread

take-up

[Gl

mechanism

[Gl

Presser

bar

(6)

bush

0

i:[>o

[0]

[01-

D

O

-[01

T-8400A,

8700A

3009M

3010M

3.

LUBRICATION

SYSTEM

3-3.

Feed

minimum

The

lubricating oil inside

Topofbed

regulator

lubrication

the

oil

coverisused

and

feed

rocker

type)

for lubricating

these

shaft

parts.

bushing

[G] Lubrication

(1)to(7) (8) Felt

A

Felt

(both

Wick

points

semi

requiring

grease

dry

and

Needle

bearing

Feed

regulator

Felt

Feed

regulator

(3) (4)

Felt

A

(5) (6)

(4) (3)

Oil

cover

T-8400A,

8700A

301IM

8

3.

LUBRICATION

SYSTEM

3-4.

(1)Wick (2)

<

Rotary

Felt

<Left

side>

Same

as

right side >

hook

base

(both

semi

<Rlght

Needle

side>

beanng

(1)

dry

and

minimum iubrication type)

Oil

tank

Air bleeding

3-5.

(1)Wick

(2 Felt

Feed

bar

(both

semi

dry

and

minimum lubrication type)

Feed

bar

3012M

©

3098M

T-8400A,

8700A

4.

ADJUSTMENT

Disassembly,

of

0

O

A

the

a qualified technician. Ask

your

carry out any

electrical

If

any

absolutely positions and

before using

Use

both

tilting it back or returning it to its original position. If

only

one

head

may

get

assembly,

sewing machine should only be

Brother

maintenance

system.

safety

devices

sure

to re-install

check

the

machine.

hands

handisused,

cause

caught.

maintenance

dealerora qualified electrician to

and

inspection of

have

been

them

that

they

operate

to

hold

the

machine

the

weightofthe

your

hand

to slip,

to their original

A

and

inspection

earned

removed,

head

and

your

CAUTION

out by

correctly

when

machine

the

be

hand

A

Tum

off

the

power

cord from

otherwise depressed When turning

result

stops

•

When

maintenance

•

When rotary

the

If

out observe

the

wall outletatthe

the

machine may

by mistake, which could result in injury.

using a clutch motor,

even

after

of

the

motor's

fully before starting work.

carrying out inspection,

replacing

hook

and

power

switch

some

adjustment, be extremely careful to

all

safety

switch

and

the

power

inertia.

consumable

knife

needstobe

precautions.

4.

ADJUSTMENT

disconnect

operateifthe

the

is switched offasa

Wait

parts

leftonwhen

the

following times,

treadle is

motor

will

until

the

adjustment

suchasthe

carrying

power

keep

motor

and

4-1.

Safety

(DD

Machine

motor

If

the

spring operating

the

safety

(2)

bed

switch

position

specifications:

strokeistoo

switch will

not

1.5mm

operate.

-T-

short,

Table

(A)

4.5mm

T-8421A, 8422A, 8722A)

The

(B)

standard

showninthe

At

the

adjusted

readjusted.

However,ifthe

the

gap

or narrower

adverse

happens,

* If the operation of

way,

depressed.

<

Adjustment

1.

Loosen

2. Move position

and

3. Tighten

installation position for

illustrationatleft.

time of shipment from the factory, dimension (A) is

to 3 mm,

between

than

effect on

adjustasfollows.

the

sewing

and

dimensionsofthe

the

machine

the

standard

the

operation of

the

machine

method

the

screw

(2).

the

safety switch (1) to

so

that

screw

the

(2).

the

tableis4.5

the

safety

switch (1) is

normally this

bed

gap

safety switch (1) is affected in this

will

does

work

table

and

the

safety

start

table

when

(1.5 mm), it may

the

not

needtobe

makeitso

hole is wider

switch (1). Ifthis

the

treadle is

>

the

gap

mm.

(B)

left or right to adjust its

between

the

safety switch (1)

have

that

an

3013M

T-8400A,

8700A

10

4.

ADJUSTMENT

4-2.

<

Measurement

Thread

take-up

method

amount

>

Pass

thread

upper

take-up

for

thread

3014M

through

take-up

The

standard

springs R (1) and L (2) Is 7 mm.

take-up [right](3)

standard

The stopper

stud

(5).

<

Adjustment

The

thread

decreases

Heightofstopper

spring

amounts

and

the

[left] (4)

take-up

when

thread

take-up

by changing

stopper[left](4). heights of

are

when

method

the

>

amount

height of

[right] (3)

length for

You

can adjust the thread

the

heights of the

the

stopper

the

are

for a

the

stopperIsIncreased.

[for

right

[right] (3)

aligned with the tension

thread

thread]

thread

take-up spring

1. Loosen the screw (6), and then slide the stopper

to

adjust

the

thread

2. Tighten

the

screw

take-up

(6).

amount.

take-up

stopper

and

[right]

the

(3)

Heightofstopper

1. Loosen

to

2. Tighten

the

adjust

the

screw

thread

screw

[ieft] (4) [for ieft

(7),

and

then

take-up

(7).

amount.

thread]

slide

the

stopper

[left] (4)

0

3015M

Note:

35mmormore

-Pull

If using a

length for

thread trimming

The 35 mm the

take-up

However, if using fine

thread

much

or it might result in thread trimming errors for

thread.

thread

the

trimming

left upper

thread

becauseofthe

trailing length is normal if

when

the

thread

amount

or finer), reducing

may

thread is pulled from

length is

shorter

of the thread take-up spring.

threads

cause

the

right

the

upper

sewing

may

twist In

the

upper

than

this,

(suchas#50

thread

threadtobe

machine,

become

the

thread.

thread

the

needle

reduce

take-up

the

shorter

length Is

the

polyester

amount

cut

too

the

left

trailing

after

hole. If

thread

too

short,

upper

Trailing

thread

3016M

11

T-8400A,

8700A

4.

ADJUSTMENT

4-3.

<

Measurement

Thread

take-up

method

>

Do not thread

Upper

measuring thread

amount

0

spring

pass

take-up

limit position

Stronger

tension

thread

Weaker

Stronger

through

when

take-up

Weaker

The standard tensions forthe thread take-up spring R (1) and thread take-up spring L (2) are as

sewing

<

Thread

1. Loosen

2. Tighten

Thread

1.

2. Use a small screwdriver to turn

3. Tighten

machine

For

foundation

For light-weight

(-nn3)

For

heavy-weight

Adjustment

take-up

the

set

to

adjust

the

tension.

the

set

take-up

Loosen

adjust

the

tension

tension.

tension

specifications.

(-firiF)

and

medium-weight materials

materials

method

spring

screw

spring

>

R (1) [for

(3), and turn

(3).

L (2) [for left

nut

(5).

nut (5).

(-flflS)

right

follows

the

thread]

the

depending on

0.25N

0.35N

0.70N

thread]

adjusting thumb (4)

tension

stud

(6) to

3017M

T-8400A,

8700A

12

4.

ADJUSTMENT

4-4.

<For

non-foundation

Do not

thread through.

<For

foundation

Pass

the

through.

Thread

pass

the

thread

take-up

speciflcatlons>

speclficatlons>

amount

(1)

Center

2928M

The thread take-up amount is adjusted by how the thread Is

passed

<

For

Do not

through the thread amount adjuster (1).

Using

the

standard

non-foundation

pass

the

thread through

thread

specifications

amount

the

adjuster

(1) >

thread amount adjuster

(1). Loosen the screw (2) and slide the thread amount

adjuster (1) to

For

foundation

Pass

the thread through the thread

the

right-side position.

specifications

amount

adjuster (1).

The standard position of the thread amount adjuster (1) is

when the

<

Adjusting

When the thread

amount adjuster (1),

less

right.

It is

amount

•

screw

(2) is in

the

when

the

thread amount

better

When with foundation specifications

When

when

nottopass

adjuster

sewing

the

thread

the

stitch length is

thread

has

(1):

heavy

take-up

the

been

the

materials

take-up

thread

the

increased

centerofthe

amountisnot

adjustment range.

amount

passed

through the thread

take-up

adjuster

thread

(1) is moved to

through

usingasewing

>

amount

enough,

becomes

the

thread

machine

such

the

as

Thread

amount

take-up

is too large

(3)-

(B) *— Thread take-up

amountIstoo

Startofmovement

2929M

3018M

small

It is

bettertopass

adjuster

(1);

• When sewing with slippery

yams

the

thread

through

threads

the

such

thread

as

amount

synthetic

• When sewing light materials

• When sewing with a stitch length of 2 mm or

• When sewing

you would like to prevent

tightening problems

<

Guidetoadjustment

The

standard

tension spring (3)

under

thread

starts

anyofthe

above

skipped

suchaslooping, or thread

>

take-up

amountiswhen

to move

when

the

less

three

conditions

stitches,

breakages

the

loop is moved to

and

thread

point (B)which is slightly in front of point (A)where the rotary hook tip catches the upper thread loop and the rotary hook

thread

amountisat

its

maximum.

• If the thread take-up amount is too large, the thread

tension spring (3)

(A) is

passed.

This can

tightening

• If

the

thread

take-up spring (3)

This

can

the

upper

The thread take-up amount required

the

typeofthread,

length,

sewing

so

adjust

conditions.

will

not start to move

cause

and

take-up

cause

thread

the

skipped stitches, poor thread

thread

breakages.

amountistoo

will

start moving before point (B).

thread

breakages,

and

pulling of

thicknessofthe

thread take-up

even

after point

small,

the

overtightening of

the

seam.

will

vary depending on

material

amount

and

to suit the

the

thread

stitch

3019M

13

T-8400A,

8700A

4.

ADJUSTMENT

4-5.

Upper

shaft

(Under-table

and

motor

lower

shaft

timing

specifications: T-8420A, 8720A)

3020M

Remove

Tilt

Remove (Gradually slide

turning

4.

Place

the mark (3) on timing pulley D (2)is aligned with

reference line (4) when

position.

(Place

gradually slide the timing belt (1) to the left while turning

the

back

machine

needle.

the

machine

the

timing belt (1).

the

machine pulley fonvard.)

the

timing belt (1) onto timing pulley D (2)sothat

the

timing belt (1) part of

pulley.)

head.

the

timing belt (1) to the right while

the

thread take-up is at its highest

the

way on

the

and

bed

then

When

the

highest

When

highest position

thread

position

the

needle

take-upisat

barisat

3021M

its

3022M

<

Adjustment

method

>

1. Check that the mark (3) on timing pulley D (2)is aligned withthe bed reference line (4) when the thread take-up is

at its

highest

Also at this time,

position.

check

that

the

<A> mark on

the

machine

pulley is visible in about the middle of the belt cover

window.

2. Check that

In

about

needle

3.

Install

the

barisat

the

needle.

the

<->

mark on

middleofthe

Its

highest

the

machine pulley is visible

belt

cover

window

position.

when

the

T-8400A,

8700A

14

4.

ADJUSTMENT

4-6.

Upper

(DD

shaft

and

lower

shaft

timing

motor specifications: T-8421A, 8422A,

3023M

3024M

8722A)

<

Before

Check that the index mark (1) on the machine pulley and the

index mark (2) on the pulley holder

* Ifthe index marks (1) and (2)

screws (3)and alignthe index marks (1) and (2).

<

Adjustment

1.

2.

Tilt

3. Remove the retaining ring (4)

and

4. Remove the screw (7), (The screw (7) into

table.)

5.

Remove

back

the

Remove

adjusting

>

method

the

needle.

the

machine

washer

(6).

canbeloosened

cut-away part in

the

quick

reverse

>

head.

and

are

aligned.

are

not aligned, loosen the

and

then remove the pin (5)

loosen

the

screw

by inserting a screwdriver

the

oil

pan

(9) underneath

solenoid

(10).

(8).

the

3025M

6. Remove the timing belt (11).

15

3026M

T-8400A,

(Gradually slide

tuming

the

8700A

the

timing belt (11) to

machine pulley forward.)

the

right while

E-

When

at its

When

its

highest

the

highest

the

thread

position

needle

position

take-up

barisat

is

3027M

4.

ADJUSTMENT

7. Place the timing belt (11) onto timing pulley D (12)sothat

the mark (13) on timing pulley D (12) is aligned with

the

bed reference line (14) when the thread take-up Is at Its

highest

(Place gradually slide the timing belt (11) to

the

<

Adjustment

1.

Check

with

position.

the

machine

that

the

bed

timing belt (11) part of

the

way on

the

left while turning

pulley.)

method

the

mark (13) on timing pulley D (12)ls aligned

reference line (14) when

>

the

thread take-up Is

and

then

at Itshighest position.

Alsoatthis

pulley Is visible In

window.

2.

Check

in

about

needle

3. Install

4.

Install

that

the

barIsat

the

quick

the

needle.

time,

check

the

<->

middleofthe

Its

highest

reverse

that

the

about

the

markonthe

belt

position.

solenoid (10).

<A>

markonthe

middle of

machine

cover

machine

the

belt

pulley Is visible

window

when

cover

the

3028M

Note:

When assembling the jointunit (15) after Ithas been disassembled,

aligned withthe center of

Sewing

machine

operating

direction

the

screw

(16) at

the

front.

T-8400A,

8700A

Install

so that the mark (18) on

timing

Securely

pulley

tighten

U (17) Is

3029M

16

4.

ADJUSTMENT

4-7.

ep

Needle

r-(4)

drop

forward-back

13.3-13.7mm

(7)-

position

3030M

3031M

<

Checking

1.

Set

2. Move

3. The

method

the

stitch length dial to "0".

the

needle

gap

between the needle

bar

>

(1) to its lowest position.

bar

(1) and

(3) should be 13.3-13.7 mm at the bottom

presser

If

adjustmentisnecessary,

<

Adjustment

1.

Remove

cover

2.

Loosen

3. Move

between

13.3-13.7

above.

4. Tighten

5.

Check (This is

bolt (6) is tightened.)

6. Install

7.

Check hole in (The

goes

whenitcomes

The * If

(5).

the

needle

into

needle

the

"4-16.

bar

bush

(2).

method

the

seven

the

bolt (6).

needle

the

needle

mm

the

bolt (6).

once

more thatthe

because

the

rear

that

cover

the

feed

will actuallybeslightly to

the

feed

out.)

screws

bar

as

the

needle

dog

>

(1)

bar

described

needle

(5).

goes

(7).

(7),

should not be touching

needle

touches

Feed

dog position").

follow

the

procedure

(4)

and

then

fonA^ardorbacksothat

(1)

and

the

in <Checking method>

gapis13.3-13.7

bar

(1) may move when the

into

the

and

will

be slightly to

the

feed dog, check

the

remove

presser

mm.

middle of

the

feed

dog

presser

edge

below.

bar

the

front

(7).

the

needle

when

the

steps

bar

of the

rear

gap

(3) is

it

back

in

Touchesiftoo

small

n n

=®

Touches

Iftoo

3032M

large

3033M

<

Reference

If

distance

•

The

feed

>

(A) Is

dog (7)

too

large

will

touch

the

needle

when

the

stitch

length dial is at the maximum setting

• Skipped stitches and needle

breakages

may occur.

• Lower thread trimming errors at the right side and upper

thread

If

distance

•

The

trimming errors at

(A) is

too

feed

dog (7) will touch

small

the

left

the

side

needle

may

occur.

when

the

stitch

length dial is at the maximum setting.

• Skipped stitches and needle breakages may occur.

• Lower thread trimming errors at

the

left

side

and

upper

thread trimming errors at the right side may occur.

17

T-8400A,

8700A

4.

ADJUSTMENT

(2)

r-(B)

^(9)

n""

3034M

3035M

Note:

When

adjusting

not

move

arm

(3) with

Ifthey

are

various when

RealignmentIfthese

1.

mechanisms,

changing to lower feed.

Set

the

2. Tighten

the

feed

3. Move bolt (5) from (B) to (C).

(Be careful not to pull bolt (5)

washer

4. Check that

the

presser

(If

gap

drop forward-back position" on

5. Move bolt (5) from (C)

(Be careful not to pull bolt (5)

washer

6.

Check

(7)

and

If

gap

1)

Loosen

2) Tum

(A)

(8) to

the

needle

the

feed

rocker

respecttothe

arm

feed

moved, they may

and

the

parts

are

stitch length dial to "0".

the

screw

(4) to

secure

rocker

shaft

(1).

(6)

may

fall down.)

the

gap

(A) between

bar

(8) is

13.3-13.7

(A) is incorrect, adjust while referring to "Needle

back

(6)

may

fall down.)

once

more

that

the

(A) Is

between

presser

Incorrect:

the

13.3-13.7

bar

screw

needle

the

(8)

(9).

bar

needle

mm.

3) Tighten the screw (9).

(Be careful not to move the needle bar rock arm (3) sideways at this time. If it is moved sideways, the

needle

bar rocker link (10) may move out of

alignment. Refer to "Needle

sideways position" on the

4) Check once more that the

needle bar (7) and

mm.

the

drop

forward-back position, do

(2)

and

the

rocker

cause

interference between the

needle

accidentally

the

out

the

mm.

the

needle

shaft

(1).

drop

position may shift

moved

feed rocker arm (2) to

too

far, othenA/ise

needle

page.)

to (B).

out

too

far, otherwise the

gap

(A)

is13.^13.7

between

mm.

the

needle

rock arm (3) to adjust the

bar

(7)

and

the

presser

bar

following

presser

gap

bar

rocker link

page

for details.)

(A) between the

(8) is 13.3-13.7

bar

rock

(7) and

the

bar

gap

bar

(8)

Do not fully bolt (5)sothis

fail

down.

(A)

13.3-13.7mm

(11)

remove

does

the not

3036M

7. Check that

hole in

Ifthe

the

needle

the

feed

touches

needle

dog (11).

the

goes

into the middle of the needle

feed dog (11), adjust

the

of the feed dog (11) to match the needle position. (Refer

to "4-16.

Feed

dog position".)

position

T-8400A,

8700A

18

4.

ADJUSTMENT

Needle

bar

rocker

f

link

sideways

s

position

§

A small *

These

* Ifno

feed

shaft

gap

(0-1

gaps

are clearance shaft

(1)

(1).

3037M

mm) is

necessary

determined by

(0-1

mm)

are

installed flush, you will

the

canbeobtained

Installthe needle bar rocker arm (3)sothat Itis flush with the

feed

rocker

shaft

(1).

* Refer to the

the

needle

on both

sides.

sideways

even

needtoadjust

following

bar

position of

though the

to check

rocker link (10).

the

needle

bar

needle

bar

the

sideways

the

sideways position of

rocker

arm

(3).

rock

arm

(3)

position of

the

and

the

feed

Gapisalmost

0 mm.

3038M

19

T-8400A,

8700A

4.

ADJUSTMENT

4-8.

(4)-

Needle

and

rotary

(A)=

hook

timing

1.

Set

the

stitch length dial to

tobesewn.

Standard

2. Remove

3. Loosen

stitch length

Specifications

-nnF

-nn3

-nns

the

rubber

the

screw

down to adjustsothat

needle

lowest position.

bar

(2) Is aligned with

bar

bracket (4) when

(Be careful not to

4. Securely tighten

5. At this time,

and

the

same

as

the

front of

each

other.

(5)

tum the gaps

the

cap

and

the

screw

(A)

feed

the

actual length of

(1).

move

the

top

the

needle

(5).

and

(B)

dog

stitch

length

the

needle

reference

the

bottom

needle

bar

(2)atthis time.)

between

(7)

should

the

stitches

dial

2 2

3

bar

(2) up or

line (3) on the

edgeofthe

bar

(2) Is at Its

the

needle

be

about

(6)

the

Needle

2.4mm

bar

lowest position

T

(3)

12mm

(A) = (B)

3039M

6. Tum the machine pulley forward to

(2) until

the

reference line ((8) or (9), depending on the

raise

the needle bar

feed condition) on the needle bar (2) Is aligned with the

bottom

edgeofthe

7. In this condition, similar,sothat

The procedure up to this point determines

amount.

Note:

If

the

• It

needle

will

bar

cause

• Both the left and right skipped stitches or thread

•

Upper

thread

needle

bar

secure

the

lift

the

needle

bar

amountistoo

poor tightening In

seams

breakages

trimming

errors

base

(4).

machine

pulley with

(2) will not move.

the

large

the

right thread.

will

become

willoccur.

may

occur,orthe

needle bar

uneven, and

thread may be cut too short (models with thread trimmer).

will

• The upper thread trailing length

with

thread

trimmer).

be too long (models

tape

upper

or

lift

Lower

feed

Needle

feed

3040M

T-8400A,

needle

• Skipped stitches

• The upper thread trailing length

with

8700A

thread

bar

lift

trimmer).

amount

and

thread

Is

too

breakages

If

the

small

will

occur.

willbetoo short (models

20

4.

ADJUSTMENT

(11) (12)

(13)

—(10)

3041M

8. Loosen the

base

(The removed from the rotary hook

(12) to prevent

9. Loosen

cover

screws

the

screws

FL (11)

(10), and then remove rotary hook

and

FR (12).

(10) is designed

them

from being lost.)

set

screws

(13) (three

so

that they cannot be

base

cover FL (11)

each

at left

and

(However, be careful not to loosen them too much,

othenvise of

the

able amount

the

set

rotary hook

to turn.

which will still allow

screws

base

Loosen

(13)

will

touch

and the pinion

the

set

screws

the

gear

by

rotary

inside surface

(14)

will

the

minimum

hooktomove

freely.)

10. Tum

11. Tighten

12.

the

rotary hook by hand to align

(15) with

the

machine pulley

the

set

(Tighten the

three

ordersothat

tilted.)

Remove

the

tape

the

rotary hook tip

middle of the needle. (Do not turn the

at

this time.)

screws

the

(13).

set

screws (13) a little bit at a time in

pinion

gear

(14)

does

not

that

is securing

the

machine

pulley.

and

FR

right).

not be

become

Color

Needle

lowest position

bar

In

Mark

Mark /

(I

(C)

1-1.5mm

(C)

3042M

3043M

13.

Useanoil-based

needle.

14. With

the

needle

while pushing with

your

finger to

(15) in

the

hollow of

15. Check that between center

holeis1-1.5

* If

the

line of

the

distance is not

again

and

* If dimension

reference by

the

If

usingathread

not

easily

bottom

needle

problem.

form

• If problems

breakages

mm to

the

Note:

•

When

upper

occur,

makeiteasier

thread

the

stitch length is

change,sore-check

• During quick

needle

will

become

0.7 mm, otherwise projection (D)

(15).

marker

raised, tum

the

pen

needle

against

makeamark

the

needle.

distance

(0)

to color in

the

machine pulley fonvard

the

rotary hook tip (15)

from

the

rotary hook tip

from

the

mark from the rotary hook tip (15)

the

needle to

mm.

adjust

(0)

line (3) on

edgeofthe

barisat

such

stable

such

as

set

the

loops

the

top

edgeofthe

1-1.5

height of

has

the

its

lowest

as

polyester

mm, loosen

the

been

adjusted,

needle

bar

needle

position, but this is

the

needle

(2)

maybehidden

bar

base

thread

skipped stitches or upper thread

the

above

distance (C) to

for the rotary hook tip (15) to

loop.

reverse

and

changed,

distance

operation, distance (C) for the left

shorter,sodo

the

rotary hook tip (15) may touch the

this could

distance

(0)atsuch

not

damage

times.

set

it to

the rotary hook tip

hollow of

intersection

and

needle

screw

bar.

the

highest

(4)

when

which

0.7-0.8

catch

(C) will

less

the

(15)

not

does

also

than

a

0.7-0.8mm

3044M

21

T-8400A,

8700A

4.

ADJUSTMENT

4-9.

Quick

reverse

device

(DD

motor

3045M

specifications:

1.

Set

the

stitch length dial 1/2 a

setting.

(For

example,ifthe

length dial to 3.5.)

2.

Tilt

back

the

machine

3.

Loosen

(The into

table.)

4. When

solenoid bracket (7)sothat

quick

then

* If

the

screw

the

cut-away part in

the

reverse

tighten

the

gap

quick

reverse

screws

(2) can be loosened by inserting a screwdriver

reverse lever (4) is fully lowered, move the

solenoid (5)

the

mentioned

T-8421A, 8422A, 8722A)

step

below

the

maximum

maximum setting is 4,

head.

(1)

and

(2).

the

oil

there

and

the

screw

(1).

aboveistoo

solenoid (5) will

pan

is no

rubber

large,

become

set

the

(3) underneath the

gap

between

stopper

the

operation

sluggish.)

(6),

stitch

the

and

of

3046M

3047M

T-8400A,

8700A

22

Brother T-8420A, T-8421A, T-8422A, T-8720A, T-8722A Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual