Brother International LK3-B434E MKII Instruction Manual - English - Page 73

17. TROUBLESHOOTING Problem Cause Check 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. The movable knife does not pick up the thread because of skipped stitches at the sewing end. Movable knife position is incorrect. Shuttle race thread guide position Needle bar lift amount Skipped stitches at sewing end Movable knife position Sub-tension is too weak. Sub-tension Sharpen or replace the fixed knife. Adjust the position of the shuttle race 36 thread guide. Adjust the needle bar lift amount. 35 Refer to "Skipped stitches occur". Adjust the position of the movable knife. 37 Turn the sub-tension nut to adjust the 29 tension. Thread take-up spring tension and height are incorrect. Incorrect needle and rotary hook timing. Shuttle race thread guide is not separating the threads. Thread take-up spring tension and height Needle bar lift amount Shuttle race thread guide position Adjust the tension and height of the 30 thread take-up spring. Adjust the needle bar lift amount. 35 Adjust the position of the shuttle race 36 thread guide. Shuttle race thread guide is not separating the threads. Upper thread is not properly tight. Shuttle race thread guide position Upper thread tension Adjust the position of the shuttle race 36 thread guide. Adjust the upper thread tension. 29 Uneven upper thread length. Upper thread length Adjust the subtension. 29 Upper thread is too long. Thread take-up lever stroke Adjust the thread take-up lever stroke. 37 Incorrect thread tightness. Upper thread tension is too weak. Upper thread tension Adjust the upper thread tension. 29 Lower thread tension is too weak. Thread take-up spring tension and height are incorrect. Lower thread tension Thread take-up spring tension and height Adjust the lower thread tension. 29 Adjust the tension and height of the 30 thread take-up spring. Inner clamping device does not operate. Work clamp pressure is too strong. Work clamp pressure Adjust the work clamp pressure so that the inner 46 clamping device operates. 67 LK3-B434E Mark II