Jack JK-T781e Machines

Cause: The tension of the tension controller No.2 is too tight
Solution: Decrease the tension of the tension controller No.2

Cause: The tension or the stroke of the take-up spring is too great
Solution: Decrease the tension or the stroke of the take-up spring

Cause: Blade point of sewing hook has burr or scratches
Solution: Buff the blade point of the sewing hook or replace the sewing hook.

Cause: Poor timing of the sewing hook
Solution: Readjust the hook's timing by the timing gauge

Cause: The thread path has scratches
Solution: Buff the thread path by cloth files, etc.,

Cause: The needle is too thin
Solution: Replace by a thick needle