Brother HE-800B Instruction Manual page 88

11. TROUBLESHOOTING
Cause
Work clamp
Rotary hook
Thread tension
Needle bar play
Lower thread clamp
Needle plate
Joint sewing
79
Check
Work clamp pressure
Relation between work
clamp assembly and
sewing length
Blunt rotary hook tip
Needle bar height and
needle bar lift amount
(The gauge is an option
part.)
Gap between the needle
and the tip of the rotary
hook
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.
Remedy
Increase work clamp pressure.
* The standard height of the adjustment screw is
approximately 30 mm, so tighten it further than this.
・Replace work clamp assembly that fits for sewing
length.
・When using knits or woven materials, replace the
parts with the -3 specification parts:
Length feed plate (for specification -3), work clamp
assembly (for knits),
specification -3)
Polish with buff or replace the part.
1. Adjust the needle bar height to "1" on the gauge.
2. Adjust the needle and rotary hook timing to "2" on
the gauge.
Adjust the gap between the needle and the rotary hook
tip to 0.01 - 0.08 mm. (Adjust to as large as possible
without causing skipped stitches to occur.)
* Move the needle bar to the left and right with your
finger, and check that the tip of the rotary hook does
not strike the needle.
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.)
HE-800B
needle plate 1.2 (for
Cam
Roller
3998Q
Screw
3999Q
Page
66
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64*
65*
66*
26, 27
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68*
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