Uneven Seams; At The Sewing Start - Brother HE-800A Instruction Manual

Cause
Thread tension
Needle bar plate
Lower thread clamp
Needle plate
Joint sewing
１６-３. Uneven seams (1) ...... At the sewing start
Cause
Upper thread
scissors
Upper thread feeding
Check
Zigzag thread upper
thread tension
Vertical and longitudinal
needle bar play
Lower thread retainer
cam
Thread scraps and dust
blocking area around
lower thread clamp and
lower thread presser
Lower thread clamping
force
Relation between material
and needle plate
Angle of work clamp
means that material is not
being clamped.
Check
Installation height
Upper thread scissors
opening timing
Upper thread scissors
operation
Thread take-up amount
Remedy
Adjust the upper thread tension appropriately.
Reduce the needle bar play, or replace the parts.
Lower thread retainer cam should be sitting firmly on
lower thread clamp plate roller.
Clean around the lower thread presser.
If the lower thread clamp and lower thread presser
are bent, replace them.
Check that the screws are tightened.
Lower thread
clamp
When using knit material, replace with the –3
needle plate.
Replace with a needle plate with a smaller needle
hole.
Replace with short work clamp that matches the
sewing length.
Use the accessory auxiliary sheet.
Process the work clamp assembly to match the
joint section. (Attach or remove rubber.)
Remedy
Adjust the upper thread scissors installation height.
Adjust to an appropriate opening timing.
Apply grease to the inclined face of the opening
cam.
Loosen the screw to decrease thread take-up
amount so that upper thread does not pull out of
scissors assembly at the sewing start.
Increase
Decrease
HE-800A
16. TROUBLESHOOTING
Cam
Roller
3998Q
Screw
3999Q
Screw
4000Q
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