Troubleshooting - Bernina 780 User Manual

Troubleshooting

In most cases you will be able to identify and remedy faults by checking the following.
Check if:
⦁ the upper and lower threads are threaded correctly
⦁ the needle is inserted correctly
⦁
the needle size is correct - check the needle/thread table page 15
⦁
the needle tip and shaft are undamaged
⦁
the sewing computer is clean - brush out any thread lint
⦁
the hook race is clean
⦁
any threads are trapped between the tension discs or under the bobbin case spring
Fault Cause
Uneven stitch
̶ upper thread too tight/too slack
formation
̶ needle blunt or bent
̶ poor quality needle
̶ poor quality thread
̶ needle/thread combination is incorrect
̶ incorrectly threaded
Skipped stitches ̶ incorrect needle system
̶ needle bent or blunt
̶ poor quality needle
̶ needle inserted incorrectly
̶ incorrect needle point
Faulty stitching ̶ remnants of thread between the
tension discs
̶ incorrectly threaded
̶ remnants of thread under the bobbin
case spring
Thread is caught
̶ upper thread breaks
in the area of the
take-up lever
1
Upper thread ̶ incorrect needle/thread combination
breaks ̶ upper thread tension too tight
̶ incorrectly threaded
̶ poor-quality or old thread
̶ stitch plate or hook tip damaged
Lower thread
̶ lower thread tension too tight
breaks
̶ stitch hole in the stitch plate has been
damaged
̶ needle blunt or bent
Repair
⦁
reduce/increase upper thread tension
⦁
use new BERNINA quality needle
⦁ use new BERNINA quality needle
⦁ use quality thread (Isacord, Mettler, Gütermann etc.)
⦁ match the needle to the thread size
⦁ check upper and lower thread
⦁ use needle system 130/705H
⦁ use new BERNINA quality needle
⦁ use new BERNINA quality needle
⦁ insert needle as far up as it will go
⦁ match the needle point to the texture of the material
⦁
fold a piece of thin material and slide the folded edge (not the
raw edges) between the thread tension discs, moving the
material back and forth to clean the right and left side of the
thread tension
⦁
check upper and lower thread
⦁
carefully remove any thread remnants from under the spring
If the upper thread breaks and the thread is trapped in the area
of the take-up lever, proceed as follows:
⦁ power switch to «0»
⦁ remove the screw 1 on the headframe with the angular Torx
wrench
⦁ pull the headframe at the bottom slighty forward, flip it
upwards a bit and remove it
⦁ remove thread remnants
⦁ attach headframe and retighten screw
⦁ match the needle to the thread size
⦁ reduce the upper thread tension
⦁ check upper threading
⦁
use quality thread (Isacord, Mettler, Gütermann etc.)
⦁
take the sewing computer to the nearest authorized
BERNINA dealer
⦁
increase the upper thread tension
⦁
take the sewing computer to the nearest authorized
BERNINA dealer
⦁
use a new needle
033804.52.04_2013-09_Manual_B780_EN
Troubleshooting
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