Brother KE-430B Service Manual page 141

Problem
Upper thread breaks.
Lower thread breaks.
Skipped stitches
occur.
Needle breaks.
Button breaks. (438)
Cause
Upper thread tension is too strong.
Needle is installed incorrectly.
Thread is too thick for the needle.
Thread take-up spring tension and
height are incorrect.
Damaged or burred rotary hook,
needle hole plate or needle.
Thread melting (synthetic thread)
Lower thread tension is too strong.
Corners of needle hole plate or
bobbin case are damaged.
Clearance between needle and
rotary hook tip is too great.
Incorrect needle and rotary hook
timing.
Driver is contacting needle more
than is necessary. (except KE-484C)
Needle is bent.
Needle is installed incorrectly.
Needle thread is too short.
Needle is touching the rotary hook.
Needle is bent.
Needle is too thin.
Needle is striking the button (438)
Needle is striking the button
KE-430B, 430C series
6. TROUBLESHOOTING
Remedy
Adjust the upper thread tension.
Install the needle correctly.
Use the correct thread for the
needle.
Adjust the tension and height of the
thread take-up spring.
File smooth or replace the affected
part.
Use a thread cooling
(optional)
Adjust the lower thread tension.
File smooth or replace the affected
part.
Adjust the needle clearance.
Adjust the needle bar lift amount.
Adjust the driver needle guard.
Replace the needle.
Install the needle correctly.
Adjust the thread take-up lever
stroke.
Adjust the needle clearance.
Adjust the needle bar lift amount.
Replace the needle.
Use the correct needle for the
material.
Refer to "6. CHECKING THE
SEWING PATTERN"
Instruction Manual.
Refer to "6. CHECKING THE
SEWING PATTERN"
Instruction Manual.
Ref.
P.5
Instruction
manual
P.5
P.5
device
P.136
P.5
P.101
P.100
P.101
Instruction
manual
P.114
P.115
P.101
P.100
P.5
Instruction
in the
manual
Instruction
in the
manual
134