Brother International LK3-B431 MKII Instruction Manual - Page 70

16. TROUBLESHOOTING Problem Cause Check Remedy Page Upper thread breaks. Upper thread tension is too strong. Upper thread tension Adjust the upper -'thread tension. 26 Needle is installed incorrectly. Needle direction Install the needle so that the groove is 23 facing forward. Thread is too the needle. thick for -Thread and needle Thread take-up Thread take-up spring tension and - spring tension and height are incorrect. height Damaged or burred rotary hook, needle hole plate or needle. Damage or burring Use the correct thread for the needle. 23 Adjust the tension and height of the 27 z thread take-up spring. File smooth or replace the afffected part. Thread melting (synthetic thread) Thread edge Use a thread cooling device (optional). 65 Lower thread breaks. Skipped stitches occur. Lower thread tension is too strong. Corners of needle hole plate or bobbin care are damaged. Clearance between needle and rotary hook ti • is too • reat. Incorrect needle and rotary hook timing. Driver is contacting needle more than is necessa . Needle is bent. Needle is installed incorrectly. Lower thread tension Adjust the lower thread tension. 26 Damage File smooth or - replace the affected part. Needle clearance Needle bar lift amount Clearance between driver and needle Bent needle Needle direction Adjust the needle clearance. 33 Adjust the needle bar lift amount. 32 Adjust the driver needle guard. 33 Replace the needle. Install the needle so that the groove is 23 facin• forward. Needle breaks. Needle is touching the rotary hook. ---I Needle clearance Needle bar lift amount. Needle is bent. Bent needle Needle is too thin. Needle and thread Adjust the needle clearance. 33 Adjust the needle bar lift amount. 32 Replace the needle. Use the correct needle for the material. .7z LK3-8430E-, 8431E-, 8432E-, 8433E- Mark II