Troubleshooting - Bernina 350PE User Manual

Troubleshooting

In most cases you will be able to identify and remedy faults by checking the following.
Check whether:
the upper and lower threads are threaded correctly
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the needle is inserted correctly with the flat side to the back
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the needle size is correct - check the needle/thread table page 22
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the needle tip and shaft are undamaged
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the sewing computer is clean - brush out any thread lint
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the hook race is clean
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any threads are trapped between the tension discs or under the bobbin case spring
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Cause
Fault
Uneven stitch Upper thread too tight/too slack
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formation Needle blunt or bent, poor-quality needle
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Needle inserted incorrectly
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Poor-quality thread
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Needle/thread combination is incorrect
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Incorrectly threaded
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Skipped stitches Incorrect needle system
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Needle blunt or bent, poor-quality needle
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Needle inserted incorrectly
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Incorrect needle point
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Upper thread breaks Upper thread tension too tight
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Incorrectly threaded
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Poor-quality or old thread
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Stitch plate or hook tip damaged
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Lower thread breaks Lower thread tension too tight
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Stitch hole in the stitch plate has been
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damaged
Needle blunt or bent
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Needle breaks Needle not correctly inserted
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Fabric was pulled
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Fabric was pushed when thick material
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used
Poor-quality thread, unevenly wound or
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knotted
Thread is caught in Upper thread breaks
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the area of the
take-up lever
Faulty stitching Remnants of thread between the tension
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discs
Incorrect threading
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Remnants of thread under the bobbin case
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spring
Sewing computer Sewing computer fails to run or runs slowly
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Repair
Reduce/increase upper thread tension
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Use new, high-quality needle (BERNINA)
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The flat side of the shank must be to the back
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Use quality threads (Isacord, Mettler, Gütermann)
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Match the needle to the thread size
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Check upper thread threading path/lower thread threading path
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Use needle system 130/705 H
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Use new, good quality needles
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Insert needle as far up as it will go
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Match the needle type to the fabric
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Reduce upper thread tension
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Check upper thread threading path
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Use high-quality thread
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Have sewing computer checked by a specialized dealer
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Reduce lower thread tension
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Have sewing computer checked by a specialized dealer
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Use new needle
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Tighten the needle clamp screw
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Do not pull the fabric during sewing
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Use the correct presser foot for thick material (e.g. Jeans foot no. 8,
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use height compensating tool when sewing over a thick seam
Use high-quality thread
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If the lower thread breaks and the thread is trapped in the area of the
take-up lever, proceed as follows:
power switch to «0» (off)
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remove the screw on the headframe with the angular Torx button
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turn headframe cover slightly to the left, then slide it upwards
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remove remnants of thread
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attach headframe and retighten screw
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Fold a piece of thin fabric and slide the folded edge (not the raw
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edges) between the thread tension discs, moving the fabric back and
forth to clean the right and left side of the thread tension
Check upper and lower thread
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Carefully remove any thread remnants from under the spring
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Plug not properly inserted
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Power switch to «0» (off)
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Sewing computer has been standing in a cold room
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033301.70.04_1007_B330_B350_B380_EN
Troubleshooting
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