Brother RH-981A User manual

RH-981A
Please read this manual before using the machine.
Please keep this manual within easy reach for quick reference.
ELECTRONIC EYELET BUTTON HOLER
SERVICE MANUAL

RH-981A
i
This service manual is intended for RH-981A; be sure to read the RH-981A instruction manual before this manual.
Carefully read the “SAFETY INSTRUCTIONS” below and the whole of this manual to understand this product before you start
maintenance.
As a result of research and improvements regarding this product, some details of this manual may not be the same as those for the
product you purchased.
If you have any questions regarding this product, please contact a Brother dealer.
SAFETY INSTRUCTIONS
1. Safety indications and their meanings
This instruction manual and the indications and symbols that are used on the machine itself are provided in order to
ensure safe operation of this machine and to prevent accidents and injury to yourself or other people.
The meanings of these indications and symbols are given below.
Indications
DANGER The instructions which follow this term indicate situations where failure to follow the
instructions will almost certainly result in death or severe injury.
CAUTION The instructions which follow this term indicate situations where failure to follow the
instructions could cause injury when using the machine or physical damage to
equipment and surroundings.
Symbols
........................................ This symbol ( ) indicates something that you should be careful of. The
picture inside the triangle indicates the nature of the caution that must be
taken.
(For example, the symbol at left means “beware of injury”.)
........................................ This symbol ( ) indicates something that you must not do.
........................................ This symbol ( ) indicates something that you must do. The picture
inside the circle indicates the nature of the thing that must be done.
(For example, the symbol at left means “you must make the ground
connection”.)

RH-981A ii
2. Notes on safety
DANGER
Wait at least 5 minutes after turnin
g
off the
p
ower switch and disconnectin
g
the
p
ower cord from the wall outlet
before o
p
enin
g
the face
p
late of the control box. Touchin
g
areas where hi
g
h volta
g
es are
p
resent can result in
severe injury.
CAUTION
Environmental requirements
Use the sewin
g
machine in an area which is free
from sources of stron
g
electrical noise such as
high-frequency welders.
Sources of stron
g
electrical noise ma
y
cause
problems with correct operation.
Any fluctuations in the power supply voltage
should be within 10% of the rated voltage for
the machine.
Voltage fluctuations which are greater than this
may cause problems with correct operation.
The
p
ower su
pp
l
y
ca
p
acit
y
should be
g
reater than
the re
q
uirements for the sewin
g
machine’s
electrical consumption.
Insufficient
p
ower su
pp
l
y
ca
p
acit
y
ma
y
cause
problems with correct operation.
The
p
neumatic deliver
y
ca
p
abilit
y
should be
g
reater than the re
q
uirements for the sewin
g
machine's total air consumption.
Insufficient
p
neumatic deliver
y
ca
p
abilit
y
ma
y
cause problems with correct operation.
The ambient tem
p
erature should be within the
range of 5 to 35 during use.
Tem
p
eratures which are lower or hi
g
her than this
may cause problems with correct operation.
The relative humidit
y
should be within the ran
g
e of
45% to 85% durin
g
use, and no dew formation
should occur in any devices.
Excessivel
y
dr
y
or humid environments and dew
formation ma
y
cause
p
roblems with correct
operation.
Avoid exposure to direct sunlight during use.
Ex
p
osure to direct sunli
g
ht ma
y
cause
p
roblems
with correct operation.
In the event of an electrical storm, turn off the
p
ower and disconnect the
p
ower cord from the
wall outlet.
Li
g
htnin
g
ma
y
cause
p
roblems with correct
operation.
Installation
Machine installation should onl
y
be carried out b
y
a qualified technician.
Contact your Brother dealer or a qualified electrician
for any electrical work that may need to be done.
The sewin
g
machine wei
g
hs more than 87 k
g
.
The installation should be carried out b
y
two or
more people.
Do not connect the
p
ower cord until installation is
com
p
lete, otherwise the machine ma
y
o
p
erate if
the start switch is
p
ressed b
y
mistake, which could
result in injury.
Be sure to connect the
g
round. If the
g
round
connection is not secure,
y
ou run a hi
g
h risk of
receivin
g
a serious electric shock, and
p
roblems
with correct operation may also occur.
All cords should be secured at least 25 mm awa
y
from an
y
movin
g
p
arts. Furthermore, do not
excessivel
y
bend the cords or secure them too
firml
y
with sta
p
les, otherwise there is the dan
g
er
that fire or electric shocks could occur.
Install the belt covers to the machine head and
motor.
If usin
g
a work table which has casters, the
casters should be secured in such a wa
y
so that
they cannot move.
Be sure to wear
p
rotective
g
o
gg
les and
g
loves
when handlin
g
the lubricatin
g
oil and
g
rease, so
that the
y
do not
g
et into
y
our e
y
es or onto
y
our
skin, otherwise inflammation can result.
Furthermore, do not drink the oil or eat the
g
rease
under an
y
circumstances, as the
y
can cause
vomiting and diarrhoea.
Keep the oil out of the reach of children.

RH-981A
iii
CAUTION
Sewing
This sewing machine should only be used by
operators who have received the necessary
training in safe use beforehand.
The sewin
g
machine should not be used for an
y
applications other than sewing.
Be sure to wear
p
rotective
g
o
gg
les when usin
g
the
machine.
If
g
o
gg
les are not worn, there is the dan
g
er that if
a needle breaks,
p
arts of the broken needle ma
y
enter your eyes and injury may result.
Turn off the
p
ower switch at the followin
g
times,
otherwise the machine ma
y
o
p
erate if the start
switch is
p
ressed b
y
mistake, which could result in
injury.
When threading the needle
When replacing the needle
When not usin
g
the machine and when leavin
g
the machine unattended
If usin
g
a work table which has casters, the
casters should be secured in such a wa
y
so that
they cannot move.
Attach all safet
y
devices before usin
g
the sewin
g
machine. If the machine is used without these
devices attached, injury may result.
Do not touch an
y
of the movin
g
p
arts or
p
ress an
y
ob
j
ects a
g
ainst the machine while sewin
g
, as this
ma
y
result in
p
ersonal in
j
ur
y
or dama
g
e to the
machine.
If an error occurs in machine o
p
eration, or if abnormal
noises or smells are noticed, immediatel
y
turn off the
p
ower switch. Then contact
y
our nearest Brother
dealer or a qualified technician.
If the machine develo
p
s a
p
roblem, contact
y
our
nearest Brother dealer or a qualified technician.
Cleaning
Turn off the
p
ower switch before carr
y
in
g
out
cleanin
g
, otherwise the machine ma
y
o
p
erate if
the start switch is
p
ressed b
y
mistake, which could
result in injury.
Be sure to wear
p
rotective
g
o
gg
les and
g
loves
when handlin
g
the lubricatin
g
oil and
g
rease, so
that the
y
do not
g
et into
y
our e
y
es or onto
y
our
skin, otherwise inflammation can result.
Furthermore, do not drink the oil or eat the
g
rease
under an
y
circumstances, as the
y
can cause
vomiting and diarrhoea.
Keep the oil out of the reach of children.
Maintenance and inspection
Maintenance and inspection of the sewing
machine should only be carried out by a qualified
technician.
Ask your Brother dealer or a qualified electrician to
carry out any maintenance and inspection of the
electrical system.
Turn off the power switch and disconnect the
power cord from the wall outlet at the following
times, otherwise the machine may operate if the
start switch is pressed by mistake, which could
result in injury.
When carrying out inspection, adjustment and
maintenance
When replacing consumable parts such as the
loopers and knife
Disconnect the air hoses from the air supply and
wait for the needle on the pressure gauge to drop
to “0” before carrying out inspection, adjustment
and repair of any parts which use the pneumatic
equipment.
If the power switch and air need to be left on when
carrying out some adjustment, be extremely
careful to observe all safety precautions.
Use only the proper replacement parts as
specified by Brother.
If any safety devices have been removed, be
absolutely sure to re-install them to their original
positions and check that they operate correctly
before using the machine.
Any problems in machine operation which result
from unauthorized modifications to the machine
will not be covered by the warranty.

RH-981A iv
Finger guard
3. Warning labels
The following warning labels appear on the sewing machine.
Please follow the instructions on the labels at all times when using the machine. If the labels have been removed
or are difficult to read, please contact your nearest Brother dealer.
Safety devices
Eye guard
Finger guard
Needle bar guard
Belt cover, etc.
3Do not touch the knife or press any objects
against the machine while sewing, as this
may result in personal injury or damage to
the machine.
5
Be sure to connect the ground. If the ground connection is not secure, you run a high risk of
receiving a serious electric shock, andproblems with correct operation may also occur.
6Direction of operation
3122Q
12
Belt cover
Needle bar guard
Eye guard
Belt cover
(Rear)
4Be careful not to clamp your fingers when
closing the front cover.

RH-981A
CONTENTS
1. MECHANICAL DESCRIPTIONS ...................1
1-1. Upper and lower shaft mechanisms..................1
1-2. Needle bar mechanism ......................................2
1-3. Thread take-up mechanism...............................2
1-4. Zigzag mechanism .............................................3
1-5. Needle bar rocking mechanism.........................3
1-6. Feed mechanism................................................4
1-7. Work clamp mechanism.....................................5
1-8. Cloth opener mechanism...................................6
1-9. Cutter mechanism...............................................7
1-10.Looper mechanism.............................................7
1-11.Spreader mechanism.........................................8
1-12.Double chain stitch looper mechanism..............9
2. DISASSEMBLY...................................................10
2-1. Covers and work clamp mechanism ...............10
2-2. Feed mechanism..............................................11
2-3. Lubrication mechanism ....................................11
2-4. Looper and spreader mechanisms..................12
2-5. Needle bar rotating mechanism.......................13
2-6. Looper base mechanism..................................14
2-7. Needle bar, thread take-up, and zigzag
mechanisms......................................................15
2-8. Knife pipe assembly..........................................17
2-9. Lower shaft mechanism ...................................17
2-10.Synchronizer mechanism.................................18
2-11.Upper shaft mechanism ...................................18
2-12.Cutter mechanism.............................................19
2-13.Zigzag fork mechanism....................................19
3. ASSEMBLY...........................................................20
3-1. Zigzag fork mechanism....................................20
3-2. Cutter mechanism.............................................21
3-3. Upper shaft mechanism ...................................22
3-4. Lower shaft mechanism ...................................23
3-4-1. Adjusting the timing belt..............................23
3-5. Upper thread trimmer mechanism...................24
3-5-1.
Adjusting the thread trimmer lever
hammer stroke ....................................................24
3-6. Knife pipe and the knife bracket.......................25
3-7. Driving gear shaft mechanism .........................26
3-8. Needle bar, thread take-up, and zigzag
mechanisms......................................................27
3-8-1. Eliminating end play of the thread take-up
on the arm ...................................................27
3-8-2. Applying grease to the ends of the thread
take-up spring..............................................27
3-8-3.Eliminating end play of the needle bar
driving lever...................................................27
3-8-4.Eliminating end play of the driving rod ........28
3-8-5.The strength to tighten the set screw
of ball bearing 25/20.....................................28
3-8-6.
Eliminating end play of the zigzag rock shaft ..... 28
3-8-7.Eliminating end play of the zigzag lever......29
3-8-8.Attaching the needle bar yoke and
the needle bar level feed link.......................29
3-8-9.Attaching the needle bar bush U and the
needle bar.....................................................30
3-8-10. Eliminating end play of
the needle bar block..................................31
3-8-11. Adjusting the needle bar
in the radial direction......................................31
3-8-12.
Attaching the needle bar block assembly ....32
3-8-13. Adjusting the height of the needle bar .....32
3-9. Looper base.......................................................33
3-10.Needle bar rocking mechanism........................34
3-10-1. Driving looper shaft...................................34
3-10-2. Needle bar rocking mechanism ...............35
3-11.Looper and spreader machanisms..................37
3-12.Lubrication mechanism.....................................40
3-12-1. Machine head ...........................................40
3-12-2. Driving gear shaft.......................................41
3-13.Feed mechanism ..............................................42
3-13-1. X direction...............................................42
3-13-2. Y direction...............................................43
3-13-3. Attaching the X-feed guide shaft...........45
3-14.Synchronizer......................................................46
3-15.Covers and work clamp mechanism................47
3-16.Safety switch......................................................47
4. ADJUSTMENT.....................................................48
4-1. Adjusting the work clamp lift height..................48
4-2.
Adjusting the position of the work clamp plate.... 49
4-3. Adjusting the cloth opening amount.................50
4-4. Adjusting the position of the work clamp..........51
4-5. Adjusting the X-axis home position..................52
4-6. Adjusting the Y-axis home position..................52
4-7. Adjusting 0 position (reference line)
of the needle......................................................53
4-8. Adjusting the home position of the
looper base........................................................53
4-9. Fine adjustment of knife position......................54
4-10.Adjusting the sideways movement
of the cutter lever...............................................55
4-11.Adjusting the height of the throat plate.............55

RH-981A
4-12.Adjusting the height of the spreader
and looper..........................................................56
4-13.Adjusting the needle and looper timing............57
4-14.Adjusting the loop stroke ..................................58
4-15.Adjusting the height of the needle bar .............59
4-16.Adjusting the clearance between
the looper and needle.......................................59
4-17.Adjusting the needle guard...............................60
4-18.Adjusting the spreader mounting positions .....60
4-19.Adjusting the spreader timing...........................61
4-20.Adjusting the amount to pull
the upper thread and tension release..............61
4-21.Adjusting upper thread trimming......................62
4-21-1.Adjusting the upper movable
knife mounting position..............................62
4-21-2. Adjusting the position of the thread
trimmer lever bracket.................................63
4-22.Adjusting the lower thread trimmer
(-01 specification).............................................63
4-22-1.Adjusting the knife pressure......................63
4-22-2.Adjusting the position of the
thread trimmer arm....................................64
4-22-3.Adjusting the thread clamp assembly
and thread clamp opener...........................65
4-22-4.Adjusting the thread handler .....................66
4-22-5.Adjusting the thread guide plate................67
4-22-6.Adjusting the amount to pull the lower
thread required for thread trimming..........67
4-22-7.Adjusting the amount to pull the lower
thread for safety stitching...........................68
4-22-8.Adjusting the amount to pull the gimp.......68
4-23.Adjusting the lower thread trimmer
(-02, -52 specifications).....................................69
4-23-1. Adjusting the knife engagement...............69
4-23-2.Adjusting the knife pressure......................70
4-23-3.Adjusting the gimp pull force.....................70
4-23-4.Adjusting the gimp tension........................71
4-23-5.Using gimp thread work clamp .................72
4-23-6.Adjusting the auxiliary clamp arm.............73
4-23-7.Adjusting the length of the lower thread
to be pulled for a safe sewing start...........74
4-24.
Adjusting the position of the lower thread presser
(-02, -52 specifications)
.....................................75
4-25.Adjusting the rotating centers
of the needle bar and the looper base.............76
4-26.Adjusting the needle bar stop position.............77
5. POWER SUPPLY EQUIPMENT.................. 78
5-1. Components inside the control box................. 78
5-2. Fuse explanation.............................................. 80
5-2-1.Before replacing a fuse............................... 81
5-3. Connectors........................................................ 82
5-3-1.Connector positions..................................... 82
5-3-2.Signal names for connectors and probable
symptoms due to poor contact ................... 86
5-4. Specification harness connections.................. 97
5-5. Summary of DIP switches................................ 98
5-5-1.Panel DIP switches .....................................98
5-5-2. Circuit board DIP switches ......................... 99
5-6. CHANGING FUNCTIONS USING
THE MEMORY SWITCHES..........................101
5-6-1. Memory switch table.................................102
5-7. Sensors positions and funstions....................103
6. AIR PRESSURE MECHANISM.................. 107
6-1. Solenoid valves and air tubes........................107
6-1-1.Adjusting the solenoid valve speed
controllers.................................................... 107
6-1-2.Air tubes.....................................................108
6-2. Air tube layout.................................................109
7. SOFTWARE.........................................................112
7-1. Motion flowchart..............................................112
7-2. Input check list................................................113
7-3. Output check list.............................................116
7-4. List of error codes...........................................118
7-5. Troubleshooting..............................................121
7-6. Control circuit block diagram (1)....................128
7-7. Control circuit block diagram (2)....................129

RH-981A

1. MECHANICAL DESCRIPTIONS
RH-981A
1
1. MECHANICAL DESCRIPTIONS
1-1. Upper and lower shaft mechanisms
1. When the motor pulley (1) rotates, its motion is transmitted to the V belt (2), the idler pulley (3), and the V belt (4),
and finally to the pulley (5).
2. When the pulley (5) rotates in the direction of the arrow, its motion is transmitted to the upper shaft timing pulley
(6), the timing belt (7), and the lower shaft tension pulley (8), and the lower shaft (9), causing the lower shaft cam
(10) to turn in the direction of the arrow.
3679Q

1. MECHANICAL DESCRIPTIONS
RH-981A 2
1-2. Needle bar mechanism
1. When the pulley rotates in the direction of the arrow (towards you), its rotation is transmitted to the upper shaft (2),
the needle bar gear (3), and the driving gear (4), that makes the eccentric rod (5) rotate.
2. The driving rod (6), which is engaged with the eccentric rod (5), rocks the needle bar driving lever (7).
3. The rocking motion of the needle bar driving lever (7) is transmitted to the needle bar york (8), the needle bar level
feed link (9), and the needle bar clamp (10), and then the needle bar (11) moves up and down.
4. The needle bar (11) is guided by needle bar bush U (12) and the needle bar block (13).
1-3. Thread take-up mechanism
1. When the pulley (1) rotates in the direction of the arrow, the needle bar gear (3) rotates via the upper shaft (2).
2. The thread take-up cam (4), which is attached to the needle bar gear (3), moves the thread take-up (6) via the
thread take-up cam roller (5).
3. The thread take-up cam roller (5) is always kept in contact with the cam (4) by the thread take-up spring (7)
attached to the thread take-up (6).
3681Q
3682Q

1. MECHANICAL DESCRIPTIONS
RH-981A
3
1-4. Zigzag mechanism
1. When the pulley (1) is turned in the direction of the arrow, its motion is transmitted to the upper shaft (2) that
rotates the zigzag cam (3), and the zigzag fork (4) rocks.
2. The zigzag rock shaft (7) is rocked by the zigzag fork (4), via the zigzag connecting rod (5), and the zigzag crank
(6).
3. The rocking motion of the zigzag rock shaft (7) is transmitted to the zigzag lever (8), the needle bar lever feed link
(9), and the needle bar block clamp (10), those move the needle bar block (11) up and down.
4. The needle bar (12) is fitted on the needle bar block (11), and the needle bar guide (14) is fitted in the notch of the
needle bar block (11). When the needle bar block (11) moves up and down, the needle bar (12) oscillates.
1-5. Needle bar rocking mechanism
1. When pulse motor R (1) operates, the motion is transmitted to the driving needle pulley assembly (2), timing belt
D (3), and the looper pulley assembly (4), which then moves the driving looper shaft assembly (5).
2. The looper base (6) is rotated by the looper pulley assembly (4).
3. When the vertical shaft T pulley U assembly (7), which is attached to the driving looper shaft assembly (5), rotates,
the motion is transmitted to timing belt U (8), and the needle bar block assembly (9) that rotates the needle bar (10).
3683Q
3684Q

1. MECHANICAL DESCRIPTIONS
RH-981A 4
1-6. Feed mechanism
[X-direction feeding]
1. When pulse motor X (1) operates, its motion is transmitted to the actuating gear (2), the idle gears (3) and (4), and
the X racks (5) and (6), that finally moves X-feed shaft holder L (7).
2. The X-feed guide shafts A (8) and B (9), which are connected to X-feed shaft holder L (7), move X-feed shaft
holder R (10).
3. The Y-feed guide shafts (11) and (12), which are attached to X-feed shaft holders L (7) and R (10), move the feed
bar (13) in the X direction.
[Y-direction feeding]
1. When pulse motor Y (14) rotates, its motion is transmitted to the actuating gear (15), the idle gear (16), timing
pulley A (17), that finally moves the Y-timing belt (18).
2. The Y-timing belt (18) is secured by the Y-driving shaft holder (19) and the belt holder (20), and that moves the Y
shaft (21).
3. The linear bush (23), which is fitted in the ball bearing (22), is fitted in the Y-guide shaft (24) to move the feed bar
(13) in the Y direction.
X direction
3685Q
Y direction

1. MECHANICAL DESCRIPTIONS
RH-981A
5
1-7. Work clamp mechanism
1. Cylinder 16 X 10 (1) moves clamp lever B (6) in the direction of the arrow according to the cylinder’s motion, via
the presser cylinder rod (2), the cylinder rod pin (3), the presser driving lever (4), and the clamp lever shaft (5).
2. The end of clamp lever B (6) is fitted on clamp lever L (7), and the work clamp (9) attached to clamp arm L (8)
lowers.
3. When the cylinder (1) is returned by the presser spring (10), the work clamp (9) rises. The speed controller (11)
attached to the cylinder (1) controls the rising speed of the work clamp (9).
* The work clamp mechanism is activated by independently-operated left and right cylinders, that can equalize the
pressure of the work clamp.
The pressure of the work clamp is always applied to the material equally even when the material thickness
changes.
3686Q

1. MECHANICAL DESCRIPTIONS
RH-981A 6
1-8. Cloth opener mechanism
1. The feed bracket (1) carries the cylinder 16 X 15 assembly (2), whose end is connected to the opening cylinder
rod (3), cylinder rod pin B (4), and the opening driving lever (5).
2. The opening connecting rod (6) attached to the opening driving lever (5) is connected to the fulcrum lever plate
(8) and the lever (9) via the slide block (7).
3. The projection (10) of the fulcrum lever plate (8) and the pin (11) of the lever (9) are fitted on the hole of the work
clamp plate (12) and the slide block on it.
4. When the cylinder 16 X 15 assembly (2) operates, and the stopper (13) of the opening driving lever (5) and the
bolt (14) make contact, the work clamp plate (12) moves in the direction of a, consequently opening a button
eyelet on the material.
5. At this time, there should be at least 1.3 mm clearance between the throat plate (15) and the needle plate (16).
Adjust the clearance using the bolt (14).
6. When the cylinder 16 X 15 assembly (2) is not pressurized, the work clamp plate (12) is moved in the direction of
b by the opening spring (17). At this time, the stopper (13) of the work clamp plate (12) makes contact with the
stopper plate (18).
* The c indicates the movement of the work clamp plate (12).
3687Q
3688Q
1.3 mm or more

1. MECHANICAL DESCRIPTIONS
RH-981A
7
1-9. Cutter mechanism
1. When cylinder 63 X 100 (1) operates, the motion is transmitted to the cylinder rod (2), link C (3), and link A (4),
which then activates the cutter lever assembly (5).
2. The cutter sensor partition plate (6) attached to link C (3), and the cutter sensor assembly (7) monitor the motion
of the cutter sensor assembly (5).
3. Engagement of the hammer (8) attached to the end of the cutter sensor assembly (5) and the cutter (9) attached
to the bed, cuts the material requiring button eyelets.
1-10. Looper mechanism
1. At the end of the looper link assembly (2) which has the looper link support shaft (1) as the pivot of the rocking
motion, the looper cam roller (3) is fitted in the groove in the lower shaft cam (4). The two looper link springs (5)
are attached to the other end.
2. The looper link springs (5) are secured by the looper driving plate (7) through which the looper driving shaft (6)
passes.
3. When the lower shaft cam (4) rotates in the direction of the arrow, the looper link assembly (2) is rocked via the
looper cam roller (3).
4. The looper driving shaft (6) moves up and down due to the motion of the looper link assembly (2).
3689Q
3690Q

1. MECHANICAL DESCRIPTIONS
RH-981A 8
1-11. Spreader mechanism
1. At the end of the spreader cam lever (2) which has the looper link support shaft (1) as the pivot of the rocking
motion, the spreader cam roller (3) makes contact with the circumference of the lower shaft cam (4), and the
spreader driving lever (5) is attached to the other end using the screw (6). The forked part of the spreader driving
lever (5) is fitted in the groove (8) of the spreader link shaft (7).
2. When the lower shaft cam (4) rotates in the direction of the arrow, the spreader cam lever (2) is rocked via the
spreader cam roller (3).
3. The spreader link shaft (7) moves up and down due to the motion of the spreader cam lever (2).
3691Q

1. MECHANICAL DESCRIPTIONS
RH-981A
9
1-12. Double chain stitch looper mechanism
1. When the looper driving shaft (1) moves up and down,
the motion is transmitted to the looper link clamp (2),
and the looper link (3), which rocks LS-holder bracket
(6) with the holder support shaft (5) secured to the
loop base (4) regarded as the pivot.
2. When the spreader link shaft (7) moves up and down,
the motion is transmitted to the spreader link base (8)
and the spreader cam link (9), which then rocks the
spreader differential cam (10) with the holder support
shaft (5) secured to the loop base (4) regarded as the
pivot.
3. The rocking motions of the LS-holder bracket (6) and the spreader differential cam (10) cause spreader L (11) to
rock.
4. In the same way, spreader R (12) is rocked.
3692Q
3693Q

2. DISASSEMBLY
RH-981A 10
2. DISASSEMBLY
CAUTION
Disassembly should only be carried out by a
qualified technician.
Turn off the power switch before disassembly,
otherwise the machine may operate if the start
switch is pressed by mistake, which could
result in injury.
Be sure to wear protective goggles and gloves
when handling the lubricating oil and grease,
so that they do not get into your eyes or onto
your skin, otherwise inflammation can result.
Furthermore, do not drink the oil or eat the
grease under any circumstances, as they can
cause vomiting and diarrhea.
Keep the oil out of the reach of children.
Disconnect the air hoses from the air supply and
wait for the needle on the pressure gauge to drop
to “0” before disassembly of any parts which use
the pneumatic equipment.
Use only the proper replacement parts as
specified by Brother.
If any safety devices have been removed, be
absolutely sure to re-install them to their original
positions and check that they operate correctly
before using the machine.
Any problems in machine operation which result
from unauthorized modifications to the machine
will not be covered by the warranty.
If disassembly is not performed in the correct order, it may be hard to remove parts. Disassemble as follows.
The following is the main points of disassembly.
2-1. Covers and work clamp mechanism
1. Remove the needle (1).
2. Remove the face plate (2), the belt cover F (3), the belt cover R (4), the top cover (5), the zigzag window cover (6),
and the driving needle guard cover (7).
3. Remove the work clamp plates R (8) and L (9).
3694Q 3695Q
3696Q

2. DISASSEMBLY
RH-981A
11
2-2. Feed mechanism
[Feed bracket]
Remove the two Y-feed guide shafts (1) toward you. The feed bracket (2) unit will come off.
[X motor unit]
Remove the motor support (3), which includes the X motor unit.
[Y motor unit]
Loosen the screw (4) of the Y driving shaft holder, pull out the Y-shaft (5) toward you, and remove the Y-feed base
(6), including the Y motor unit.
2-3. Lubrication mechanism
1. Remove the wick supports (1) and (2).
2. Remove the wicks (3) and (4) from the hole.
3. Remove the two screws (5) and wick support L (6).
3697Q 3698Q
3699Q
Hole
Oil tank

2. DISASSEMBLY
RH-981A 12
2-4. Looper and spreader mechanisms
1. Loosen the two set screws (2) of the set collar (1), and the two set screws (3), and remove the looper link support
shaft (4).
2. Position the needle at its lower position. Pull the spreader link shaft (5) downward, and remove the spreader cam
lever (6).
3. Remove the two bolts (7) and the looper link springs (8).
4. Loosen the two set screws (10) of the set collar (9) and the two set screws (11), and remove the looper link
support shaft (12).
5. Slide the lower shaft cam (13) in the direction of the arrow, and remove the looper link (14).
3700Q
3701Q