Brother International LK3-B431 MKII Instruction Manual - Page 71

Problem Cause Check 16. TROUBLESHOOTING Remedy Page Upper thread is not trimmed. Thread jamming. Poor seam finish on reverse side of material. Fixed knife is blunt. Fixed knife blade Movable knife does not pick up the thread. I- Shuttle race thread guide position Needle bar lift amount The movable knife does not pick up the thread because of skipped stitches at the sewing end. Skipped stitches at sewing end Movable knife position is incorrect. Movable knife position Sub-tension is too weak. Sub-tension Sharpen or replace the fixed knife. ■ Adjust the position of the shuttle race 33 thread guide. Adjust the needle bar lift amount. 32 Refer to "Skipped stitches occur". Adjust the position of the movable knife. 34 Turn the sub-tension nut to adjust the 26 tension. Thread take-up spring tension and hei • ht are incorrect. Incorrect needle and rotary hook timing. Shuttle race thread guide is not separating the threads. Thread take-up spring tension and hei• ht Needle bar lift amount Shuttle race thread guide position Adjust the tension and height of the 27 thread take-up spring. Adjust the needle bar lift amount. 32 Adjust the position of the shuttle race 33 thread guide. Shuttle race thread guide is not separating the threads. Shuttle race thread guide position Adjust the position of the shuttle race 33 thread guide. Upper thread is not properly tight. Upper thread tension. Adjust the upper thread tension. 26 Uneven upper thread length. Upper thread length Adjust the subtension. 26 Upper thread is too long. Thread take-up lever stroke Adjust the thread take-up lever stroke. 34 Incorrect thread tightness. Upper thread tension is too weak. Lower thread tension is too weak. Thread take-up spring tension and hei•ht are incorrect. Upper thread tension Lower thread tension Thread take-up spring tension and hei•ht Adjust the upper thread tension. 26 Adjust the lower thread tension. 26 Adjust the tension and height of the 27 thread take-up spring. LK3-B430E-, 8431E-, B432E-, B433E- Mark tl 64