Brother BL6200 User manual

4. 1998.
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•This service manual is complied for repairing service of DOMESTIC SEWING MACHINE.
BL6200, 6700
PS1000, 1250, 1800, 1950, 2000, 2100
STAR 10, 15, 20, 20E, 30E, 40E
MYSTAR 15
•Use this manual with Parts Catalogue for fault findings when you make a repair.
•This machine is manufactured based on up-to-date product specifications at the time of this issue, but
there may be changes of specifications for improvements.
Contact manufacturer or local sales company for such changes.
Brother industries, Ltd.
Nagoya, Japan
CONTENTS
I. PRINCIPAL MECHANISMS......................................................................... 1
II. TROUBLES AND CHECK POINTS ............................................................. 11
III.HOW TO ADJUST THE ELEMENTS........................................................... 21
IV.HOW TO CHANGE THE PARTS................................................................. 58
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1. Always use rubber gloves when handling a printed circuit board, and do not touch the metal portion of the
printed circuit board with bare hands.
2. Keep the human body earthed to avoid generating static electricity.
3. Pack a printed circuit board with aluminum foil and avoid impact with it while storing or transporting.
4. Do not touch or damage the metal portion of a printed circuit board with a screwdriver or anyother tool
during repairing.

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I.
1. MECHANICAL CHART(B338, B346, B347, B348) .............................. 2
1. MECHANICAL CHART (B341, B349, B351, B352) .............................. 3
2. POWER TRANSMISSION CHART ...................................................... 4
3. DISPLAY SYSTEM BY MICRO-COMPUTER ...................................... 8
3. DISPLAY SYSTEM BY MICRO-COMPUTER ...................................... 9
4. MAIN MOTOR CONTROLLED BY MICRO-COMPUTER .................... 10

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1. MECHANICAL CHART (B338⋅B346 ⋅B347 ⋅B348)
* This part is not installed on the B346 since it is a 4-step BH model.

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1. MECHANICAL CHART (B341 ⋅B349 ⋅B351 ⋅B352)
* These parts are not installed on the B341, B351 and B352 since they are LCD models.

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2. POWER TRANSMISSION CHART
(A) Generating mechanism of needle bar, thread take-up lever and zigzag movements
(B338 ⋅B346 ⋅B347 ⋅B348)
Thread take-up
lever Eccentric counter weight Upper shaft Pulley
Needle bar
crank rod
Needle bar
clamp
Needle bar Needle bar
supporter
Needle Selecting cam
Pattern cam
Worm gear
Z finger
Zigzag connecting
rod assembly

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(A) Generating mechanism of needle bar, thread take-up lever and zigzag movements
(B341 ⋅B349 ⋅B351 ⋅B352)
Thread take-
up lever Eccentric counter weight Worm gear Pulley
Needle bar
crank rod
Needle ba
r
clamp
Needle bar Needle bar
supporter
Needle
Pattern cam
Zigzag connecting
rod assembly Z finger Selecting cam
Upper shaft

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(B) Mechanism of feed dog and oscillating hook movement
* These parts are not installed on the B338, B346, B347 and B348.
Lower shaft
gear
Outer
rotary hook
assembly
Feed dog
Feed bar
Vertical feed
cam
Drop lever
Horizontal
feed plate
* Rotary shatter
Feed pattern
cam
Feed finger
Feed regulator
Horizontal
feed shaft
Horizontal feed cam
Forked
connecting rod
Horizontal
feed arm
Lower shaft
Timing belt
Timing pulley D
Worm gear Pulley
Motor belt
Motor

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(C) Automatic 1-step BH mechanism (B338 ⋅B341 ⋅B347 ⋅B348 ⋅B349 ⋅B351 ⋅B352)
BH change
shaft BH change arm BH stopper BH cam BHF finger assembly
BH Iever
BH foot
Feed control
cam (BH) BHF finger assembly
2-(A)
2-(B)

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3. DISPLAY SYSTEM BY MICRO-COMPUTER (B341 ⋅B351)
An 8 bit micro-computer in models installed with an LCD (liquid crystal display) regulates the LCD controller
driver which controls the information shown on the display.
<1 LINE DISPLAY SYSTEM BLOCK CHART>
Power supply
circuit and
motor control
circuit
LCD panel
LCD controller
driver
(SED1278)
8-bit MCU
(M38004M8)
Contrast
volume
Message key
Pattern
sensor BH Iever SW Bobbin winder SW
Motor control
P.C. board
LCD unit