Brother PC-420 Operation Manual page 145

Symptom
The upper thread was not threaded
correctly, or the bobbin is incor-
rectly installed.
The spool is incorrectly installed.
The combination of fabric, thread
The fabric is
and needle is not correct.
wrinkled.
The needle is bent or blunt.
If thin fabrics are being sewn, the
stitch is too coarse.
The thread tension is incorrect.
The upper thread was not threaded
correctly.
The combination of fabric, thread
and needle is not correct.
Stitches are
skipped.
The needle is bent or blunt.
The needle is incorrectly installed.
Dust has accumulated under the
needle plate or in the shuttle.
Dust has accumulated in the feed
dogs or in the shuttle.
The upper thread was not threaded
correctly.
A high-pitched
noise is made
The shuttle is scratched, or has a
while sewing.
burr on it.
A bobbin designed specifically for
this machine is not used.
The needle
The needle was not raised.
threader cannot
be used.
The needle is incorrectly installed.
The presser foot that is used is not
appropriate for the type of stitch that
you wish to sew.
The stitch is not
The thread tension is incorrect.
sewn correctly.
The thread is tangled, for example,
in the shuttle.
Probable Cause Remedy
Correctly thread the upper thread
and correctly install the bobbin
thread.
Correctly install the spool.
Select a thread and needle that are
appropriate for the type of fabric
being sewn.
Replace the needle.
Shorten the stitch length or sew with
stabilizer material under the fabric.
Adjust the tension of the upper
thread.
Correct the upper threading.
Select a thread and needle that are
appropriate for the type of fabric
being sewn.
Replace the needle.
Correctly install the needle.
Remove the needle plate cover and
clean the shuttle.
Clean the shuttle.
Correct the upper threading.
Replace the shuttle.
Contact your retailer or the nearest
authorized service center.
Incorrect bobbins will not work prop-
erly. Only use a bobbin designed spe-
cifically for this machine.
Press the needle position button to
raise the needle.
Correctly install the needle.
Attach the presser foot that is appro-
priate for the type of stitch that you
wish to sew.
Adjust the tension of the upper
thread.
Remove the tangle thread. If the
thread is tangled in the shuttle, clean
the shuttle.
Reference
page 22, 24
page 24
page 33
page 34
page 56
page 54
page 24
page 33
page 34
page 35
page 135
page 135
page 24
–
page 18
page 27
page 35
page 128
page 54
page 135
Troubleshooting 139