Brother DB2-B705-100, DB2-B705-200, DB2-B705-400, DB2-B705-500 Service Manual
SERVfCE
MANUAL
BROTHER
-1
00·-200·-400·-500
(
FOR
MODEL
DB2-B705
\
r
----
BROTHER
INDUSTRIES,
NAGOYA,
JAPAN
.
LTD.,
PREFACE
Thi
s service manual is
tr
imm
er seri
es,
Norma
l troubl
es occur
made
BROTHER
in your
for the
Model 082-8705-100 Series .
sew
purpo
se
of getting
ing room will be solved wi
acquai
nted with our newly designed
th
the knowledge
of instruction manual
thread
encl osed
this
knowled
Incide
however, if you u
We sincerely hop e th
pamphlet.
with th
se
rvi
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ge on this machine by this servi
ntall
e machine, however,
manual ma
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this
covers
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the description on
with ot
at
you wi
her bran's, pi
ll
overco
in order
ce
manual
our
ease
me the
to
get
much m
bette
r ma intenance. We duly h
as well
newly developed
refer to one
tro
ubles which
ore perfect
as instruction
BROTHER
published by
may ari
BROTHER INDUSTR
knowledge
manuals
Needle Positioning Motor,
tho
se
manufa
se
in
ope
and
your
on
this machine,
that
you
parts catalog
cture
r.
factory wi
IES,
get full
ues.
th
this
LTD
.
CONTENTS
1.
Features.......................................................................................................................... 1
2.
Specifications................................................................................................................... 2
3.
N arne of major components.............................................................................................. 3
4.
Thread trimming mechanism............................................................................................. 3
5.
Construction chart of Brother
6.
Electric circuits................................................................................................................ 9
7.
Setting
8.
Test running ...................................................................................................................
9.
Sewing tensions................................................................................................................
10.
Adjusting
up
the machine . .. .. .. . .. . . . . . . . . . . .. .
on
sewing machine . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . .
N.
P.
Motor . .. .
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. . . 8
13
17
18
20
(1) Adjusting thread trimming mechanism ..........................................................................
(2)
Adjusting tension releaser . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .
(3)
Adjusting thread wiper ................................................................................................
(4)
Adjusting qichback device ............................................................................................
(5)
Adjusting presser lifter ................................................................................................
(6)
Adjusting synchronizer .................................................................................................
11.
Adjusting motor ...............................................................................................................
12.
Maintenance of motor . . . . . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. .. . . . . . . . . . . .. . . . . . . . . .. . . . . . . .. . . . . . . . . .
13.
Trouble shooting . . . . . . . . . . . . . . . .. . . . . . . . . . .
(1)
In relation with the sewing machine bead.....................................................................
(2)
In relation with control box and
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N.
P.
Motor
.. ..
..
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..
..
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..
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..
.. . .. .. .. .
..
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..
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20
24
25
25
26
27
28
31
35
35
..
.. .
37
1. Features
(Head)
1..
It ensures high graded sewing conditions and perfect durability
stitches per minute.
2.
It is equipped with built-in bobbin winder with compact design and high performance.
3.
Belt cover
4.
Plunger pump is adopted
at
slow speed operation. This pump can be easily disassembled by the mechaics.
(Thread trimming mechanism)
5.
Simple thread trimming mechanism is adopted
and maintenance and it also features very safe construction.
6.
Stable thread trimming jobs can be obtained because of the thread trimming mechanism driven
by lower shaft.
7.
Rotary knife around rotary hook is adopted to do faster trimming jobs and thread tails are
shortened considerably
8.
All
accessories including feed dogs, presser feet and needle plates can be used with this machine
in
other words, such parts are common with other lock stitch sewing machines.
9.
Built in thread wiper ensures much productivity.
is
at
maximum high speed of
equipped with as standard accessories, thus it ensures operators' safety.
on
this machine, thus it ensures perfect oil return to oil reservoir even
on
in
co~parison
with
this machine, so that it
the
conventional machine.
is
quite easy adjustment
(-200)
4,500
10.
11.
(N.P.
12.
13.
14.
15.
The
solenoid reverse mechanism operates with a soft touch and permits even the beginner to sew
backward easily. (Type
The
pneumatic thread cutter sewing machine has a presser lifter which can be controlled with a
single pedal operation and thus prevents operator fatigue. (Type
Motor)
This motor is newly designed with clutch mechanism
215
r.p.m., thus it ensures faster actions of thread trimming and stopping jobs.
400
specifications)
500
specifications)
on
slow speed motor with the speed of
Even the beginner can use this machine with single treadle pedal for inching, sewing, needle
and down position and thread trimming.
Synchronizer
is
designed with "Lead Switch" and all control circuits are not used with relays, thus
its reliability and durability are very high.
Printed Circuit Boards (P.C.B.)
are
very easy to change and all components are designed to do so,
which ensures easy maintenance.
up
- 1 -
S pacifications
DB2-B705-100 DB2-B705-200 DB2-B705-400
Means of thread trimming
Means of thread releasing Electro-magnetic solenoid
Thread wiper Nil
Quick back
Aut
refuter presser foot
High speed:
Sewing speed
Slow
speed:
Rotary hook
Motor
Electro-magnetic,
Nil
Nil
"BROTHER"
MD-931-811
rotary
MD-931·812
knife
system
Equipped
215
Solenoid
r.p.m.
MD-931-814
400W
Nil
Nil
4,500 s.p.m.
Specially designed hook
Needle Positioning
3 phase
thread
type
Nil
Motor;
DB2-B705-500
trimming
Air
Air
or
the
MD-931-815
device.
type
type
like.
(NOTE)
1.
Single
2.
Specs. on
phase
machine
motor
is
of
different specs.
head
is
referred
to
the
instruction
manual
of Model DB2-B705.
-
2-
3.
Name
This machine is componed of the following
components.
(1)
(2)
(3)
4.
Thread
of
major
Head
a.
Head
b.
Thread trimming mechanism
c. Treadle pedal
d.
Tension releaser
e. Synchronizer
f.
Thread wiper (Optional parts for
Control box
Needle Positioning Motor
trimming
components
mechanism
-200)
(1) Construction
As per Fig.
trimmer clutch
thread finger
and Solenoid
(2) Procedures
I)
At high speed
As per Fig.
cam and holder is stationed.
1,
there are composed of thread
0.
Holder
G.
Holder plate
fj.
2·1,
fj,
Knife
0.
e.
Stopper C),
stopper presses down
Lower
Fig.
1
1~1-
-
3-
Fig.
2·1
II)
At
thread trimming signal comes from synchronizer
With your heel, when you presses down the
treadle pedal, synchronizer will order to get
thread trimming signal, solenoid is going to pull
its plunger and stopper, then cam jumps up with
the aid of the spring action. (Fig.
III)
Holder's rotation
When the cam jumps up, its pin
the same circumference with the projected portion
(li),
of clutch
clutch.
At
that
stopper is positioned
it contacts with the face of holder. (Fig.
thus holder rotates together with
time, solenoid is already disengaged and
at
its original position and
2-2)
0 is located in
2-3)
I>"<:
I><
I_.
I.
Solenoid
I:>< I ..
OFF
Fig.
2-2
N) Just before ending thread trimming
As holder is rotating to the position of afore-
),
mentioned position ( I
cam, thus cam is pressed down. (Fig.
stopper
is
climbing up to
2-4)
Solenoid
c><L
r><J"'
OFF
0
Cam begins to press down
Fig.
2-3
Fig. 2-4
-4-
V)
At
ending thread trimming
Cam gradually pressed down is
circumference of clutch, then holder stops.
At
that
time, the inertia of holder is absorbed
by stopper. (Fig.
2-5)
out
of the
Solenoid
OFF
(3)
How
to
be trimmed upper and
As per the afore-mentioned procedures, upper and
lower threads
I )
The
At this time. needle comes up
its lowest position, but the signal for thread
timming is given
(Fig.
are
trimmed as follows:
hook point gets upper thread
at
its lowest position.
3-1)
lower
2.2
mm from
threads
1><1
..
1><:1"'
Fig.
2-5
II) Knife moves
Signal for thread trimming is given and by
the action of clutch, knife moves with
hook's rotation. (Fig.
3-2)
rotary
- 5 -
III)
Knife catches upper thread and lower thread
finger gets lower thread
The
point of kinfe comes into upper and lower
threads which is separated by the
and the tringle-shaped loop which is formed by
needle hole of the needle plate, thus the upper
and lower thread is separated. (Fig.
At this time, the thread take-up lever is positioned
at
a bit higher point from its lowest position,
(upper shaft angle; appr.
3-4
and
3-5,
the threads are separated.
In case of sooner or
separation of upper and lower threads, then it
causes error of thread trimming.
330·) and
later
timing, it affects on
rotary
3-3)
as
hook
per Figs.
..
")
Fig.
Fig.
3-4
3-5
-
6-
N) Upper and lower threads are trimmed
As per the above procedure, the upper and
lower threads which are caught by knife
holder are timmed by the sharp edge of knife
gradually expanded by their own shape.
At
this time, the position of thread take-up
lever is up highest. Due to the shape of the
knife, not so as to be pulled the upper thread
with excessive tension, the tension releaser
functioned to release the upper thread without
any resistance.
The
threads which were caught by knife and
holder are very much affected on the length
of threads out of needle eye and bobbin case,
and finally on the formation of the first stitch
at
the beginning of the next stitch. (Fig.
(4) Tension releaser
In case that the signal for thread trimming is
given, the tension release solenoid
pulled tension release lever
release bar
connecting
discs
(t.
In
case that the signal for needle
8 with the intermediate action of
bar
0 and plate 8 and opened tension
0 is functioned,
f),
pushed tension
up
position
given the tension release solenoid is off, thus
are
tension discs
closed. (Fig.
4)
3-6)
is
is
Fig.
3-6
(5) Thread wiper
In case that the signal for needle
given, with the interval of
wiper solenoid
0 is
10-lOOms, the thread
on,
thus thread wiper 0 is
up
position is
functioned with the intermediate action of lever
0 and grooved link
O·
In case that the thread wiper solenoid is off,
thread wiper returns to its original position with
the aid of spring. (Fig.
5)
I>;=~=='
~--......._
Fig.
Fig.
4
5
-
7-
(6) Quickback mechanism
When the backtack button is pushed, reverse sole-
noid
0 (Type
operates to lower reverse handle 8 via lever
and connecting link C).
as
ward
pushed.
When the backtack button is released, a reset
spring moves it back to its original position so
that
the machine sews forward again. (Fig.
long
400)
or reverse cylinder (Type
The
machine sews back-
as
the backtack button is kept
500)
f)
6)
.
---------------
Fcg.
6
(7) Automatic presser lifter (Type
When the power is switched
inside presser lifter cylinder
the piston, which drives knee lifter
f)
operating link
presser foot. (Fig.
When the treadle top plate is slightly stepped on,
the air pressure inside presser I ifter cylinden
decreases to lower the presser foot.
to push up push rod 8 and the
7)
500)
on,
the
air
0 increases to move
8 via piston
pressure
0
Fcg.
7
-
8-
--........
5.
Construction
chart
of
Brother
N. P.
Motor
0 Synchronizer
f)
Needle up position
8 Needle
0 Thread trimming
0
0 Main
Slow
down
speed
motor
position
motor
-9-
f)
Clutch lever
0 Brake
0 Clutch
tii)
Switch
CD
Treadle pedal
for
thread trimming
Fig. 8
6.
Electric
circuits
0
=±
-
-
-100,
-200,
,\,C
ll.C
• 12\"
-400
12\' 0 •
Type
8
ll.C
12\'.
-l
0
24\'
AC
27V
SV
~--
____
12\'
I
j
11.1"
-
10-
Fig.
9
I
-500
Type
I
-
11
-
~
~-
D.C
0.
Electric source SW
f).
Pilot lamp
@).
Transformer
8.
P.
C.
B.
for
e.
9P plug
0.
Wiper
coil
8.
Tension releaser coil
0.
Trimmer
C).
Main
tli).
Mark
G).
Fuse
(8. 7P plug
tl). Slow speed
coil
motor
tl. 3P plug
Cl.
Wiper
SW
(D. Logic circuit
$.
Brake coil
C]!).
Clutch coil
electric source
motor
fl). 4P plug
•·
6P plug
fD.
Needle
up
t».
Needle
down
fj.
Trimming
fJ.
Safety
SW
fl). 3P plug
fi.
Micro SW
tj.
Micro SW for trimming
fi.
Control box
@).
Stands
.:I!).
Transformer
i).
P.C.B.
e.
6P plug
1).
Back SW
@).
Back coil
6).
2P plug
~.
Foot pedal
for
for
bushings
for
electric source
SW
high speed
for
control box
(1
) Switching
In case that you may switch
on
on,
whatever position of synchronizer may
be,
the brake is functioned
not to move the sewing machine. This is so-called safety guard.
In case you will find that the needle is not positioned to be
treadle pedal
(2)
Pressing
By
pressing the treadle pedal lightly, micro-switch
at
215
By
pressing the treadle pedal further, the clutch contacts high speed motor, then, the sewing machine
r.p.m., by the slow speed motor.
pedal
on
on
its
rear
front end
end, thus needle comes
up
and stops.
is
engaged, then the sewing machine runs slowly
up
the kighest, you may press the
runs fast.
(3) Needle
In case
the sewing machine runs slowly by the slow speed motor and stops
(4)
Thred trimming, thread wiping and needle up position
After the needle down position, in case you may press the
down
that
you may put
position
the
treadle pedal to be a neutral position, the micro-switch is disengaged,
at
needle down position.
rear
end of the treadle pedal, the sewing
machine runs slowly by the slow speed motor, thread trimming and tension releasing mechanisms are
functioned, then the sewing machine stops
take
note
that
In this case, please
you may fail to trim the threads if you press the treadle pedal so
quickly. Also, when the sewing machine stops
rear
the
end of the treadle pedal, the sewing machine does not run nor thread trimming • may be
at
the needle up position, and thread wiper is functioned.
at
the needle up position, even though you may press
functioned.
(5) Thread trimming, non-thread wiping and needle
In case
that
you would like to do the sewing jobs without thread wiping, switch off the thread wiper
up
position
switch on the control box.
-
12-
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