Bernette Chicago 7 Instruction Manual page 126

Trouble Shooting
Problem Cause
The upper thread tension is too tight.
•
The upper thread is not threaded cor-
•
rectly.
The needle is too heavy for the fabric
•
being sewn.
The stitch length is too long for the
•
fabric.
The presser foot pressure is not cor-
•
rectly adjusted.
The correct presser foot is not used.
•
The upper thread tension is too tight.
•
Thread is caught in the hook.
•
• The feed dog is packed with lint.
Lint has collected on the hook or nee-
•
dle bar.
The needle is damaged.
•
• Slight humming sound coming from
internal motor.
• Thread is caught in the hook.
The feed dog is packed with lint.
•
Poor quality thread.
•
The bobbin case is threaded incor-
•
rectly.
Fabric has been pulled.
•
124
Correction
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502020.83.11_2013_06_bernette chicago 7_EN
Loosen the thread tension.
Rethread the machine.
Choose a needle to suit the thread
and fabric.
Adust the stitch length.
Adjust the presser foot pressure.
Select the correct foot.
Loosen the thread tension.
Remove the upper thread and the
bobbin case, turn the handwheel
backwards and forwards by hand
and remove the thread remnants.
Clean the hook and feed dog as
described.
Replace the needle.
Remove the upper thread and the
bobbin case, turn the handwheel
backwards and forwards by hand
and remove the thread remnants.
Select a better quality thread.
Remove the bobbin case, thread and
reinsert correctly.
Do not pull the fabric while sewing, let
it be fed by the machine.
Reference
16
12
19/20
30
17
127-132
16
120/121
120/121
15
120/121
19/20
11