Brother KE-430B Service Manual page 142

6. TROUBLESHOOTING
Problem
Upper thread is not
trimmed.
Thread jamming.
Poor seam finish on
reverse side of
material.
Incorrect thread
tightness.
Machine does not
operate when power
is turned on and foot
switch is depressed.
Inner clamping device
does not operate.
(434, 435, 436)
135
Cause
Movable knife is blunt.
Fixed knife is blunt.
Movable knife does not pick up the
thread.
The movable knife does not pick up
the thread because of skipped
stitches at the sewing end.
Movable knife position is incorrect.
Sub-tension is too weak.
Thread take-up spring tension and
height are incorrect.
Incorrect needle and rotary hook
timing.
Shuttle race thread guide is not
separating the threads. (except
KE-484C)
Shuttle race thread
se parating the threads insufficiently.
(except KE-484C)
Upper thread is not properly tight.
Uneven needle thread.
Needle thread is too long.
Needle is striking the button (438)
Upper thread tension is too weak.
Lower thread tension is too weak.
Thread take-up spring tension and
height are incorrect.
Head position switch does not work.
Work clamp pressure is too strong.
KE-430B, 430C series
Replace the movable knife.
Sharpen or replace the fixed knife.
Adjust the position of the shuttle
race thread guide. (except KE-484C)
Adjust the needle bar lift amount.
Refer to "Skipped stitches occur".
Adjust the position of the movable
knife.
Turn the sub-tension nut to adjust
the tension.
Adjust the tension and height of the
thread take-up spring.
Adjust the needle bar lift amount.
Adjust the position of the shuttle
race thread guide.
guide is
Adjust the position of the shuttle
race thread guide.
Adjust the upper thread tension.
Adjust the sub-tension.
Adjust the thread take-up lever
stroke.
Refer to "6. CHECKING THE SEWING
PATTERN" in the Instruction Manual.
Adjust the upper thread tension.
Adjust the lower thread tension.
Adjust the tension and height of the
thread take-up spring.
Check if the head position switch
cord is disconnected.
Adjust the position of the switching
plate.
Replace the head position switch if
it is broken.
Adjust the work clamp pressure so
that the inner clamping device
operates.
Remedy Ref.
P.118
-
P.120
P.118
-
P.120
P.102
P.100
P.134
P.116
P.117
Instruction
manual
P.5
P.100
P.102
P.102
P.5
Instruction
manual
P.114
P.115
Instruction
manual
P.5
P.5
P.5
Instruction
manual
P.130
P.132