Brother LZ2-B855E User manual

SERVICE MANUAL
ELECTRONIC SINGLE NEEDLE ZIGZAG LOCK STITCHER
ELECTRONIC SINGLE NEEDLE ZIGZAG LOCK STITCHER WITH THREAD TRIMMER
Please read this manual before ma ing any adjustments.
LZ2-B855E
LZ2-B856E

LZ2-B855E,B856E
This service manual is intended for B855E, B856E; be sure to read the B855E, B856E 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
1Safety indications and their meanings
This service 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 equip-
ment 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”.)
i

LZ2-B855E,B856E
2Notes on safety
CAUTION
Use the sewing machine in an area which is free
from sources of strong electrical noise such as
high-frequency welders.
Sources of strong electrical noise may cause prob-
lems 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 power supply capacity should be greater than
the requirements for the sewing machine's elec-
trical consumption.
Insufficient power supply capacity may cause
problems with correct operation.
The ambient temperature should be within the
range of 5°C to 35°C during use.
Temperatures which are lower or higher than this
may cause problems with correct operation.
Environmental requirements
The relative humidity should be within the range
of 45% to 85% during use, and no dew formation
should occur in any devices.
Excessively dry or humid environments and dew
formation may cause problems with correct op-
eration.
Avoid exposure to direct sunlight during use.
Exposure to direct sunlight may cause problems
with correct operation.
In the event of an electrical storm, turn off the
power and disconnect the power cord from the
wall outlet.
Lightning may cause problems with correct op-
eration.
Machine installation should only be carried out
by a qualified technician.
Contact your Brother dealer or a qualified electri-
cian for any electrical work that may need to be
done.
The sewing machine weighs more than 37 kg. The
installation should be carried out by two or more
people.
Do not connect the power cord until installation
is complete, othewise the machine may operate
if the treadle is pressed by mistake, which could
result in injury.
Be sure to connect the ground. If the ground con-
nection is not secure, you run a high risk of re-
ceiving a serious electric shock, and problems with
correct operation may also occur.
Installation
All cords should be secured at least 25 mm away
from any moving parts. Furthermore, do not ex-
cessively bend the cords or secure them too
firmly with staples, otherwise there is the danger
that fire or electric shocks could occur.
install the belt covers to the machine head and
motor.
If using a work table which has casters, the cast-
ers should be secured in such a way so that they
cannot move.
Be sure to wear protective goggles and gloves
when handling the lubricating oil, so that no oil
gets into your eyes or onto your skin, otherwise
inflammation can result.
Furthermore, do not drink the oil under any cir-
cumstances, as it can cause vomiting and diarrhea.
Keep the oil out of the reach of children.
ii
DANGER
Wait at least 5 minutes after turning off the power switch and disconnecting the power cord from the wall
outlet before opening the face plate of the control box. Touching areas where high voltages are present can
result in severe injury.

LZ2-B855E,B856E
CAUTION
This sewing machine should only be used by op-
erators who have received the necessary training
in safe use beforehand.
The sewing machine should not be used for any
applications other than sewing.
Be sure to wear protective goggles when using
the machine.
If goggles are not worn, there is the danger that
if a needle breaks, parts of the broken needle may
enter your eyes and injury may result.
Turn off the power switch at the following times,
otherwise the machine may operate if the treadle
is pressed by mistake, which could result in in-
jury.
●When threading the needle
●When replacing the needle and bobbin
●When not using the machine and when leaving
the machine unattended
If the actuator is pressed by mistake when using
the correction sewing function, the needle will
move in a zigzag motion while the machine is
operating, and injury may result.
Sewing
If using a work table which has casters, the cast-
ers should be secured in such a way so that they
cannot move.
Attach all safety devices before using the sewing
machine. If the machine is used without these
devices attached, injury may result.
Do not touch any of the moving parts or press
any objects against the machine while sewing,
as this may result in personal injury or damage
to the machine.
For machines with automatic presser lifter, do not
touch the solenoid section, otherwise burns may
result.
If an error occurs in machine, or if abnormal
noises or smells are noticed, immediately turn
off the power switch. Then contact your nearest
Brother dealer or a qualified technician.
If the machine develops a problem, contact your
nearest Brother dealer or a qualified technician.
Turn off the power switch before carrying out
cleaning, otherwise the machine may operate if
the treadle is pressed by mistake, which could re-
sult in injury.
If using a work table which has casters, the cast-
ers should be secured in such a way so that they
cannot move.
Cleaning
Be sure to wear protective goggles and gloves
when handling the lubricating oil, so that no oil
gets into your eyes or onto your skin, otherwise
inflammation can result.
Furthermore, do not drink the oil under any cir-
cumstances, as it can cause vomiting and diar-
rhoea.
Keep the oil out of the reach of children.
Maintenance and inspection of the sewing ma-
chine 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
treadle is pressed by mistake, which could result
in injury.
●When carrying out inspection, adjustment and
maintenance
●When replacing consumable parts such as the
rotary hook
If the power switch needs to be left on when car-
rying out some adjustment, be extremely careful
to observe all safety precautions.
Maintenance and inspection
Turn off the power switch before connecting and
disconnecting the plugs, otherwise damage to the
control box may result.
If using a work table which has casters, the cast-
ers should be secured in such a way so that they
cannot move.
Use only the proper replacement parts as speci-
fied by Brother.
If any safety devices have been removed, be ab-
solutely 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.
iii

iv LZ2-B855E,B856E
★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.
1
2
3
Moving parts
may cause injury.
Operate with safety devices.
Turn off main switch before
changing needle, cleaning
etc.
Safety devices
qFinger guard
wThread take-up guard cover
eBelt cover
rBelt casting prevention guide
tfinger guard, etc.
3Warning labels
4•If the actuator is pressed by mistake when us-
ing the correction sewing function, the needle
will move in a zigzag motion while the machine
is operating, and injury may result.
Hazardous voltage
will cause injury.
Turn off main
switch and wait 10
minutes before
opening this cover.
Un voltage non adapt
provoque des blessures.
Eteindrel’interrupteur et
attendre 10 minutes
avantd’ ouvrir le capot
Hochspannung
verletzungsgefahr!
Bitte schalten sie den
hauptschalter aus und
warten sie 10 minuten,
bevor sie diese
abdeckung ffnen.
Un voltaje inadecuado
puede provocar las
heridas.
Apagar el interruptor
principal y esperar 10
minutos antes de abrir
esta cubierta.
•Be sure to connect the ground. If the ground connection is not secure, you run a high risk of
receiving a serious electric shock, and problems with correct operation may also occur.
5
6•Direction of operation

v
LZ2-B855E,B856E
•Automatic presser foot lifter (B856E-90 |, option)
3
Oil pan
5
6
4e
1
5
1
2
5
w
q
t
e
r
1117S
1113S
1115S
1114S
1116S

LZ2-B855E,B856E
CONTENTS
1. MACHINE SPECIFICATIONS ................... 1-01
2. SEWING PATTERN TABLE ....................... 2-01
3. MECHANICAL DESCRIPTIONS
3-1. Needle bar and thread take-up mechanism
.................................................................. 3-01
3-2. Lower shaft and rotary hook mechanism .. 3-01
3-3. Zigzag mechanism .................................... 3-02
3-4. Presser foot mechanism ...........................3-03
3-5. Feed mechanism ...................................... 3-04
3-6. Lubrication ................................................ 3-06
3-7. Thread trimmer mechanism (B856E) ........ 3-07
3-8. Tension release mechanism ..................... 3-08
3-9. Thread wiper mechanism (B856E) ........... 3-09
4. DISASSEMBLY
4-1. Cover ........................................................ 4-01
4-2. Presser mechanism .................................. 4-02
4-3. Needle bar mechanism ............................. 4-02
4-4. Zigzag mechanism .................................... 4-03
4-5. Rotary hook mechanism ...........................4-04
4-6. Feed mechanism ...................................... 4-04
4-7. Thread trimmer mechanism (B856E) ........ 4-05
4-8. Thread wiper mechanism (B856E-40[ ], -90[ ])
.................................................................. 4-06
4-9. Panel ......................................................... 4-07
5. ASSEMBLY
5-1. Thread trimmer mechanism (856E) .......... 5-01
5-2. Feed mechanism ...................................... 5-02
5-3. Zigzag mechanism .................................... 5-03
5-4. Needle bar mechanism ............................. 5-04
5-5. Rotary hook mechanism ...........................5-05
5-6. Presser mechanism .................................. 5-06
5-7. Panel ......................................................... 5-07
5-8. Cover ........................................................ 5-08
5-9. Thread wiper mechanism (B856E-40[ ], -90[ ])
.................................................................. 5-09
6. ADJUSTMENTS
6-1. Adjusting the thread tension spring .......... 6-01
6-2. Adjusting the presser foot height .............. 6-02
6-3. Adjusting the feed dog height ................... 6-02
6-4. Adjusting the feed dog angle .................... 6-03
6-5. Adjusting the forward/back, right/left position
of the feed dog .......................................... 6-03
6-6. Adjusting the stitch length ......................... 6-04
6-7. Adjusting the needle and feed mechanism
timing ........................................................ 6-05
6-8. Adjusting the forward/back position of the
needle bar ................................................. 6-06
6-9. Adjusting the right/left position of the needle
bar ............................................................. 6-07
6-10. Adjusting the needle bar height ................ 6-08
6-11. Adjusting the needle and rotary hook timing
.................................................................. 6-09
6-12. Adjusting the hook stopper position .......... 6-09
6-13. Adjusting the synchronizer ........................ 6-10
6-14. Adjusting the rotary hook lubrication amount
.................................................................. 6-11
6-15. Adjusting the lubrication amount of the needle
bar ............................................................. 6-12
6-16. Adjusting the tension release of thread trim-
ming (B856E) ............................................ 6-13
6-17. Adjusting the thread trailing length after thread
trimming (B856E) ...................................... 6-14
6-18. Adjusting the triming of the thread trimming
(B856E) ..................................................... 6-15
6-19. Adjusting the tension of the lower thread
presser spring (B856E) ............................. 6-16
6-20. Adjusting the thread wiper (B856E) .......... 6-16
6-21. Adjusting the reverse feed assembly
(B855E/BT,B856E) .................................... 6-17
7. TROUBLESHOOTING ...................................... 7-01
8. ELECTRIC COMPONENTS
8-1. Precautions at the time of adjustment ...... 8-01
8-2. Components inside the control box .......... 8-01
8-3. Fuse explanation ...................................... 8-04
8-4. Connectors ............................................... 8-06
8-5. Summary of DIP switches ......................... 8-17
8-6. Memory switches ...................................... 8-18
8-7. Parameters ............................................... 8-21
8-8. Speed parameter ...................................... 8-24
8-9. Initialization ............................................... 8-25
8-10. List of error codes ..................................... 8-25
8-11. Troubleshooting ........................................ 8-27
8-12. Control circuit block diagram .................... 8-34

LZ2-B855E,B856E
1. MACHINE SPECIFICATIONS
1-01
1. MACHINE SPECIFICATIONS
BROTHER INDUSTRIES, LTD.
LZ2-B855E-3
MADE IN JAPAN
BROTHER INDUSTRIES, LTD.
LZ2-B856E-103
MADE IN JAPAN
BROTHER INDUSTRIES, LTD.
LZ2-B855E-0/BT
MADE IN JAPAN
<with back tack/condense device *1>
*1 ...Used for sewing condensed stitches and backtack stitches.
Upper thread feeding device
Thread trimmer
Thread wiper
Automatic presser foot lifter
Solenoid
Solenoid
Solenoid
B856E 3 4 9
Back tack/condense device *1 Solenoid
Solenoid
Single-phase/Eine Phase 110V, 220V, 230V
Maximum electric power consumption: 600 VA
*2 ...If fine adjustments to the stitch length are needed, use “General (foundation)”.
*3 ... At the time of shipment from the factory, the maximum sewing speed is set to 4,500 rpm. If you would like to sew
at speeds higher than this, change the setting of the DIP switch inside the control box. (Refer to instruction manual
page 163.)
Furthermore, the maximum sewing speed may be limited by the type of sewing pattern and the zigzag width.(Refer
to instruction manual page 84.)
*4 ... The maximum number of custom-made patterns that can be stored is 99 patterns with a total of 10,000 stitches, at
500 stitches or less per pattern.
*5 ...If you would like to reduce the pressure of the presser foot (such as when sewing light-weight materials), replace
the compression spring with the accessory spring. (Refer to instruction manual page 134.)
Use
Maximun stitch length
Presser foot height
Automatic
Presser foot pressure
Needle
Motor
Power supply
B855E B856E
-1 -3
2.5mm
5,000rpm*3
14 patterns of eight types built-in
(Up to 99 different types of custom-made patterns can be added*4)
10mm (Standard factory setting: 8mm)
Rotary thread take-up
33.3mm
1mm
6mm
10mm
7mm
20-60N*5
Schmets
SY 1965 Nm 70/10
Three-phase 400 W induction motor
General
(long stitch)
General
(foundation)
General
(long stitch)
General
(foundation)
-M01
5mm 5mm
20-60N20-60N20-60N*5
2.5mm
Sewing pattern
Max. zigzag width
Thread take-up lever
Needle bar stroke
Feed dog height
Presser bar lifter
Knee lifter
For light-weight materials-medium-weight materials
Max. sewing speed
-M03

LZ2-B855E,B856E
2. SEWING PATTERN TABLE
2-01
2. SEWING PATTERN TABLE
•This sewing machine is equipped with the following built-in sewing patterns. Select the pattern number from the
operation panel to use a pattern. (Refer to instruction manual page 71.)
•Different zigzag widths and zigzag lengths can be set for each sewing pattern. (Refer to instruction manual page 53
and 77.)
Pattern no. (LED display)
Straight stitch
Plain zigzag
2-step zigzag
3-step zigzag
Notes
Sewing pattern
Crescent scallop
(24sts.)
Even scallop
(12sts.)
Standard scallop
(24sts.)
Even scallop
(24sts.)
Crescent scallop
(24sts.)
Scallop (left)
Scallop (right)
Blind stitch (left)
Blind stitch (right)
Custom made pattern
If is set in the column marked with , a reflection pattern can be
sewn by stopping the sewing machine and then pressing the ac-
tuator. (Refer to instruction manual page 73.)
Standard scallop
(24sts.)
Even scallop
(24sts.)
Even scallop
(12sts.)
<Reflection pattern>
Sewing pattern
Press the actuator
(Reflection pattern)
Sewing direction
In the columns marked with , the number of stitches sewn in a
straight line can be set within the range of 1 to 99 stitches.
✻
(No. of stitches)
Sewing patterns created using the BAS-PC/300 (optional device) can
be sewn.
(The pattern number is set in the columns marked with .)
✻

3. MECHANICAL DESCRIPTIONS
3-01 LZ2-B855E,B856E
Operate in the order of the numbers in the illustration.
The ●, ■and other symbols with the numbers indicate different sequences of operation which can occur at the same
time.
3. MECHANICAL DESCRIPTIONS
3-1. Needle bar and thread take-up mechanism
3-2. Lower shaft and rotary hook mechanism
1091S
●5. Needle bar connecting rod
4. Thread take-up lever shaft
3. Thread take-up crank
2. Upper shaft
■7. Needle bar
■6. Needle bar clamp
■5. Rotary thread take-up lever
1. Pulley
2. Upper shaft
3. Timing pulley U
6. Lower shaft
7. Lower shaft gear
13. Rotary hook
10. Bevel gear
12. Rotary hook shaft 11. Bevel gear
9. Driving shaft
8. Driving gear
5. Timing pulley D
4. Timing belt
1. Pulley
1119S

3. MECHANICAL DESCRIPTIONS
3-02
LZ2-B855E,B856E
3-3. Zigzag mechanism
<High-speed damper mechanism>
1. Pulse motor
4. Zigzag connecting rod
Home position sensor
6. Needle bar bracket
7. Needle bar
5. Joint
2. Motor lever
3. Rocker bracket
1096S
Eccentric shaft
Plate spring
1097S
When pulse motors are used for high-speed drive control, vibration inevitably occurs. This new
mechanism uses a spring plate to absorb the inertial reaction force generated during high-speed
operation quickly and efficiently. The new electronic zigzag mechanism allows sewing at high
speed with no pattern distortion.

3. MECHANICAL DESCRIPTIONS
3-03 LZ2-B855E,B856E
3-4. Presser foot mechanism
2020
20 20
1098S
1124S
1. Adjustment screw
2. Presser spring
3. Presser bar
4. Presser foot
8. Guide bracket
9. Presser bar
10. Presser foot
7. Lifter lever
6. Connecting rod
5. Knee lifter lever
4. Knee lifter bar
3. Knee lifter
complying bar
2. Knee lifter shaft
1. Knee lifter
3. Guide bracket
2. Lifter lever
1. Presser bar lifter
5. Presser foot
4. Presser bar
1099S
<B856E-90[ ]>
1100S
3. Knee lifter complying bar assy
2. Knee lifter shaft
1. Presser foot lifter

3. MECHANICAL DESCRIPTIONS
3-04
LZ2-B855E,B856E
3-5. Feed mechanism
<Dial feed mechanism>
●6. Feed rocker shaft
●8. Feed bracket
●7. Feed rocker bracket arm
Feed dog
●9. Front or back
■5. up or down
●2. Level feed eccentric wheel
●3. Connecting rod
●5. Feed rocker arm
●■1. Lower shaft
Feed regulator
●4. Side connecting rod
■2. Lower shaft end (eccentric)
■4. Feed bracket
■3. Feed lifting link 1101S
4. Connecting rod
5. Shaft
3. Feed regulator
2. Tip of screw
1. Stitch length dial
8. Spring
7. Feed regulator
6. Connecting rod
The angle of the feed regulator can be
changed by turning the feed adjustment dial.
1126S
Feed rocker arm Connecting rod
Side connecting rod
Feed regulator
The horizontal feed amount
changes when the angle of the
feed regulator is changed.
1127S

3. MECHANICAL DESCRIPTIONS
3-05 LZ2-B855E,B856E
< Back tack mechanism >
3. Shaft
4. Condense regulator
(Touch the tip of screw)
5. Tip of screw
7. Feed regulator
6. Connecting rod
Condense dial
1. Reverse stitching lever
2. Lever guide
The angle of the feed regulator when the backtack lever is pressed down can
be changed by adjusting the condense dial.
When the condense dial is turned to the - (minus) side of the scale, the angle
of the feed regulator becomes greater and reverse feeding is carried out.
1102S
B855E/BT
B856E-30[ ]
-40[ ]
-90[ ]
1105S

3. MECHANICAL DESCRIPTIONS
3-06
LZ2-B855E,B856E
3-6. Lubrication
●4. Needle bar
connecting rod
(Disperse oil)
●3. Wick
●5. Felt
Rotary hook
Rotary hook shaft
Lubrication adjustment screw
(Adjust the lubrication amount)
B
CFilter
A
●2. Oil case
1. Plunger pump
1109S
1107S
1108S
Absorb oil
Supply oil
CA
B
From filter
1128S
1129S
■6. Oil cap screw with hole
■5. Felt
■4. Oil valve
■3. Rotary hook shaft
■8. Oil wick felt
■7. Supply oil felt
■M2. Oil lip
M4. Adjusting screw
M5. Bed
M3. Bush F

3. MECHANICAL DESCRIPTIONS
3-07 LZ2-B855E,B856E
3-7. Thread trimmer mechanism (B856E)
1130S
8. Thread trimming cam
5. Driving rod plate
6. Main lever assy
11. Movable knife
10. Driving lever
9. Knife driving rod
4. Driving rod
3. Solenoid lever
2. Solenoid joint
1. Thread trimmer solenoid
7. Roller
1131S
Clutch
Fixed knife
Spring
Movable knife

3. MECHANICAL DESCRIPTIONS
3-08
LZ2-B855E,B856E
2. Lifter lever
1a. Presser bar lifter
1b. Connecting rod (When press the knee lifter)
3. Tension release plate
4. Tension release stud
5. Tension release pin (Put the disc presser)
7. Rotary disc
Tension release pin
6. Disc presser
3-8. Tension release mechanism
<Tension release of thread trimming (B856E)>
1111S
2. Link
3. Lever
5. Tension release
connecting rod
6. Tension release plate
4. Lever
1. Solenoid
8. Tension release pin
7. Tension release stud

3. MECHANICAL DESCRIPTIONS
3-09 LZ2-B855E,B856E
3-9. Thread wiper mechanism (B856E)
<Upper thread feeding mechanism (B856E)>
1112S
3. Lever
Thread feeding is delayed by the
amount of space in the slot.
2. Link
1. Solenoid
4. Base
5. Wire
1132S
1. Thread wiper solenoid
6. Spring
2. Thread wiper rod
3. Thread wiper connecting rod
4. Thread wiper crank
5. Thread wiper

LZ2-B855E,B856E
3. MECHANICAL DESCRIPTIONS
3-10

4. DISASSEMBLY
4-01 LZ2-B855E,B856E
Disassemble each part in order of the numbers.
4-1. Cover
4. DISASSEMBLY
20 20
10. Flat screws (7 pcs)
4. Thread take-up
guard assy
7. Thread take-up
mounting plate
5. Flat screws
(3 pcs)
3. (2 pcs)
6. Rotary thread take-up lever
8. Flat screw
9. Thread guide 2. Needle
11. Face plate
12. Face plate packing
1. (Loosen)
13. (6 pcs)
15. Rear cover packing
14. Rear cover
1081S
DANGER
Wait at least 5 minutes after turning off the power switch and disconnecting the power cord from the wall
outlet before opening the face plate of the control box. Touching areas where high voltages are present can
result in severe injury.
CAUTION
Turn off the power switch before disassembly, oth-
erwise the machine may operate if the treadle is
depressed by mistake, which could result in injury.
Disassembly of the sewing machine should only be
carried out by a qualified technician.
Use only the proper replacement parts as specified
by Brother.
If any safety devices have been removed, be ab-
solutely sure to re-install them to their original
positions and check that they operate correctly
before using the machine.
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 may result. Further-
more, do not drink the oil or eat the grease un-
der any circumstances, as they may cause vom-
iting and diarrhea.
Keep the oil out of the reach of children
Any problems in machine operation which result
from unauthorized modifications to the machine
will not be covered by the warranty.
Caution knife