LH4-B800E
5 - 9
5. Troubleshooting guide
Cause
Check
Solution
page
Rotary hook
Needle height when
rotary hook point
aligned with needle
center
(Needle bar height and
needle bar rise)
Refer to "5-1. Needle thread breakage"
Thread chips on rotary
hook edge
Remove thread chips
Especially, check it in case needle
thread is man-made fiber filament
yarn
-
Machine
stopping
position
Upper shaft pulley
stopping position
Adjust the needle up
sensor position.
Refer to instruction manual
Bobbin
thread
Lower thread retaining
amount
Refer to "5-3. Uneven seams 1)......Beginning of sewing (2) Lower
thread lifted up"
Lower thread snapping
Reduce the lower
thread retaining speed
(presser foot rise
speed).
Change using the memory switch.
-
(Instruction)
Lower thread snapping
Lower thread retainer,
lower thread clamp and
lower thread presser
plate finish
Finish so that lower thread does not
snap.
-
Lower thread clamp
timing
Refer to "5-3. Uneven seams 1)......Beginning of sewing (2) Lower
thread lifted up"
Sewing start
speed
Slow speed
Reduce the slow start
speed.
-
(Instruction)
Slow start stitches
Reduce the number of
slow start stitches.
-
(Instruction)
Bar tack
thread
tension
Bar tack thread tension
is too strong.
Adjust so that whip
stitches are formed at
the sewing start.
-
(Instruction)
Upper thread
breakage
Upper thread breaks.
Refer to "5-1. Needle thread breakage"
Содержание LH4-B800E
Страница 55: ...LH4 B800E 2 30 2 DISASSEMBLY ...
Страница 87: ...LH4 B800E 3 32 3 ASSEMBLY ...