Brother LK3-B448E - Manual (Page 76)

69
18. Troubleshooting
LK3-B448E MARK II /BA-16
Check Remedy Problem Cause Page
Corners of needle hole
plate or bobbin case
are damaged.
Damage
Lower thread tension
Lower thread tension
is too strong.
File smooth or replace
the affected part.
Adjust the lower thread
tension.
Lower thread breaks.
28
Needle is installed
incorrectly.
Needle direction
Upper thread tension
Upper thread tension
is too strong.
27
Install the needle so
that the groove is facing
forward.
Adjust the upper thread
tension.
Upper thread breaks.
27
Thread takeup spring
tension and height are
incorrect.
Thread takeup spring
tension and height
Thread and needle
Thread is too thick for
the needle.
29
Adjust the tension and
height of the thread
takeup spring.
Use the correct thread
for the needle.
27
Damage or burring
Damaged or burred
rotary hook, needle
hole plate or needle
File smooth or replace
the affected part.
Needle down setting
Needle clearance
Needle bar lift amount.
Bent needle
Needle is touching the
rotary hook.
Needle is striking the
button.
Needle is bent.
Wayward stitches
Adjust so that the
needle drops down into
the hole of the button.
Adjust the needle bar
lift amount.
Adjust the needle
clearance.
Replace the needle.
40,46
Needle breaks.
Needle and thread
Needle and feed
timing
Needle is too thin.
Use the correct needle
for the material.
Adjust the needle
down detection
position.
42
41
52
Incorrect needle and
rotary hook timing
Needle bar lift amount
Needle clearance
Clearance between
needle and rotary hook
tip is too great.
41
Adjust the needle bar lift
amount.
Adjust the needle
clearance.
Skipped stitches occur.
42
Needle is bent. Bent needle
Clearance between
driver and needle
Driver is contacting
needle more than is
necessary.
Replace the needle.
Adjust the driver needle
guard.
42
Needle direction
Needle is installed
incorrectly.
Install the needle so
that the groove is facing
forward.
27