Brother PR-620 Operation Manual page 222

Symptom
The thread tension does not
correspond to the amount that
the thread tension knob was
tightened.
There are loops in
the upper thread.
The thread quality is poor.
Lint may be wound in the hook.
The upper thread is not threaded
correctly.
The machine is
noisy.
The hook is damaged.
Not enough oil was applied.
The needle is not at the correct
position.
Recommended needles are not
The needle
used on this machine.
threader cannot
be used.
The needle is not installed
correctly.
The hook on the automatic
needle-threading mechanism is
bent.
The upper thread is not threaded
correctly.
The thread
The bobbin thread is not
tension is
correctly threaded.
incorrect.
The lower thread tension is
incorrect.
The upper thread If a short length of thread
comes out of the remains after the thread is
needle when trimmed, the needle may
embroidering become unthreaded when
begins. embroidering begins again.
The upper thread There is no more thread in the
does not reach the bobbin, the thread does not feed
bobbin thread from the bobbin, or the thread
when that is fed from the bobbin is too
embroidering short.
begins.
Probable Cause Remedy
If the thread tension cannot be
adjusted, thread wax and dust
may have collected in the upper
or middle thread guide plates,
causing the thread tension guide
plates to rise. Clean the thread
tension guide plates.
Try sewing with different thread.
If the problem no longer occurs
after the thread is changed, the
thread quality is the problem.
Replace the thread with one of
good quality.
Clean the hook.
Check the thread path, and then
thread the upper thread again.
Replace the hook.
Consult your nearest authorized
dealer.
Oil recommended parts.
Touch the key to move the
desired needle bar to be
threaded into embroidering
position.
Replace and use recommended
needle.
Correctly install the needle.
Consult your nearest authorized
dealer.
Check the thread path, and then
thread the upper thread again.
Correctly thread the bobbin
thread.
Adjust the tension of the bobbin
thread.
Set the remaining length of
thread to "LONG TAIL" on the
second page of the settings
screen.
Correctly thread the lower
thread.
Reference Page
p.193
p.35
p.196
p.40
p.15, 63
p.15, 63
p.15, 63
p.35
p.19
p.85
p.150
p.19
Troubleshooting 205
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