Brother KE-430HX Service Manual page 183

Cause
Hook Needle bar height and
needle bar lift amount
Gap between needle and
the tip of the shuttle hook
Hook lubrication
Thread twisted around hook
Flaw on the tip of the shuttle
hook and shuttle hook edge
Lower thread Lower thread tension
Bobbin case Damage outside of bobbin
case and bent bobbin holder
spring, etc.
Heat (of needle or Install needle cooler
thread)
Air amount for needle cooling
Air direction for needle
cooling
Check
Adjust the needle bar height.
Adjust the needle and hook timing.
Adjust the gap between the needle and the tip of the
shuttle hook to 0.01 - 0.08 mm. (Adjust to as large as
possible without causing skipped stitches to occur.)
* Move the needle bar back and forth with your finger,
and check that the tip of the shuttle hook does not
strike the needle.
・ Too small quantity of lubrication oil will cause thread
breakage. Adjust the quantity of lubrication oil.
Remove any twisted thread from the inner and shuttle
hook.
Polish with buff or replace the part.
* Use the KE-430H/BE-438H bobbin case.
Adjust the lower thread tension appropriately.
Buff it to correct the damage, or replace the part.
* Use the KE-430H/BE-438H bobbin case.
When using synthetic thread, use the needle cooler
(silicone oil).
Remove any dust and thread scraps inside the air
cylinder cover.
Adjust the height or lateral position of the air nozzle for
needle cooling to point to the needle.
KE-430HX/KE-430HS, BE-438HX/BE-438HS
Remedy
More oil
Less oil
13. TROUBLESHOOTING
Page
135*
136*
137*
4076B
*
*
132,
Instruction
manual
*
Instruction
manual
Instruction
manual *
145*
172