Brother BAS-311F-L - Manual (Page 76)

14. TROUBLESHOOTING
BAS-311F-0, 311F-L, 326F-0
69
Problem Cause Check Remedy Page
Thread is too thick for
the needle.
Thread and needle
Upper thread breaks.
Thread take-up spring
tension and height are
incorrect.
Thread take-up spring
tension and height
Damaged or burred
rotary hook, needle hole
plate or needle.
Damage or burring
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.
25
21
Upper thread tension is
too strong.
Upper thread tension
Adjust the upper thread
tension.
25
Needle is installed
incorrectly.
Needle direction
Install the needle so that the
groove is facing forward.
21
Thread melting
(synthetic thread)
Thread edge
Use a thread cooling
device.
21
Thread path is incorrect. Thread
Pass the thread correctly
along the thread path.
22
Lower thread tension is
too strong.
Lower thread tension
Corners of needle hole
plate or bobbin case
are damaged.
Damage
Adjust the lower thread
tension.
File smooth or replace
the affected part.
25
Incorrect needle and
rotary hook timing.
Needle bar lift amount
Skipped stitches occur.
Driver is contacting needle
more than is necessary. Clearance between
driver and needle
Needle is bent. Bent needle
Adjust the needle bar lift
amount.
Adjust the driver needle
guard.
Replace the needle.
43
42
Clearance between needle
and rotary hook tip is too
great.
Needle clearance
Adjust the needle clearance.
the affected part.
43
Needle is installed
incorrectly.
Needle direction
Install the needle so that the
groove is facing forward.
21
Needle bar lift amount
Needle breaks. Needle is bent. Bent needle
Needle moves about. Needle and thread
Adjust the needle bar lift
amount.
Replace the needle.
Select the correct needle for
the sewing conditions.
Reduce the sewing speed
21
42
Needle clearance
Adjust the needle clearance.
the groove is facing forward.
43
Needle is too thin. Needle and thread
Use the correct needle
for the material.
Needle is touching the
rotary hook.
Lower thread breaks.