Brother International DB2-B791 Service Manual - Page 50

TROUBLESHOOTING GUIDE 1. Machine head Problem Cause Improper needle installation Bent needle. Blunt needle tip, jammed eye. Check Needle facing, height Needle Solution Reinstall needle. Page z Replace needle. Needle breakage Improper timing feed --I Needle bar rise Improper needle to rotary hook timing Needle bar height HNeedle to rotary hook gap Thread wiper too high Thread position wiper Adjust feed timing. 32 Adjust needle to 31 rotary hook timing. Adjust needle to 31 rotary hook timing. Adjust needle to 31 rotary hook timing. Adjust thread wiper. 45 Thread breakage Improper threading threading Rethread. Bent needle. Blunt needle tip, jammed eye. Improper needle installation Excessive needle thread tension Excessive bobbin thread tension Loose needle thread Insufficient rotary hook lubrication Needle Needle facing, height Needle tension thread Bobbin thread tension Thread take-up spring operation Oil supply Replace needle. Reinstall needle. Adjust needle 5 thread tension. Adjust bobbin 5 thread tension. Adjust thread takeup spring. 5 Adjust oil supply. - 53 -