Troubleshooting; Machine Head - Brother DH4-B981 Instruction Manual

11. TROUBLESHOOTING

11. TROUBLESHOOTING
If there is a problem with operation, first check that the threads are correctly threaded and that the needle is correctly
installed.

MACHINE HEAD

Problem
Thread breaks.
Skipped stitches occur.
Needle breaks.
72
Cause
Thread tension control nut pressure
is too strong.
Thread is of poor quality.
Thread is too thick for the needle.
Needle groove or needle hole are
not smooth.
Needle and looper adjustment is
incorrect.
Needle, looper, throat plate or
thread path is damaged.
Thread tension control nut pressure
is too strong or too weak.
Needle point is broken or bent.
Needle and looper adjustment is
incorrect, or clearance is incorrect.
N e e d l e a n d n e e d l e g u a r d
adjustment is incorrect.
Looper tip is blunt.
Needle is bent.
Needle and looper adjustment is
incorrect.
N e e d l e a n d n e e d l e g u a r d
adjustment is incorrect.
DH4-B981
Remedy
Adjust to an appropriate pressure.
Use a better-quality thread.
Use a differently-sized needle.
Replace with a new needle.
Adjust the needle bar height or the
looper and spreader height.
Repair the damage with an oilstone
or buffer, or replace the damaged part.
Adjust to an appropriate pressure.
Replace with a new needle.
Adjust correctly.
Adjust correctly while referring to
"9-6 Adjusting the needle guard."
Repair with an oilstone or replace
the looper with a new one.
Replace with a new needle.
Adjust the needle bar height or the
looper and spreader height.
Adjust correctly while referring to
"9-6. Adjusting the needle guard."
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