Brother International PR-620 Users Manual - English - Page 219

APPENDIX Symptom Probable Cause Sliding surface on hook is not smooth. There are burns on it. 1 Remedy Reference Page Consult your nearest authorized dealer. The upper thread breaks. 1 Hook race area The thread is loose in the hook area. The play between the hook and the race is too much. The hook does not rotate smoothly. The space between the hook stopper and the hook cannot be adjusted. The upper thread is not threaded correctly. Remove the loose thread. If the thread is tangled in the hook, clean the hook. Consult your nearest authorized dealer. Remove lint, and clean and apply oil. Consult your nearest authorized dealer. Pull the upper thread by hand from below the presser foot, and check that the thread moves smoothly. If the thread does not move smoothly, it is not correctly threaded. Un-thread the machine and re-thread the machine. Make sure the thread is correctly positioned in the needle bar thread guide. p.193 p.193, 196 p.35-38 Upper thread is not positioned in upper or middle thread guide. There are knots or tangles in the thread. The upper thread tension is too high. The lower thread tension is incorrect. The thread does not roll out of the bobbin case smoothly. The bobbin case is damaged. The bobbin thread is not wound correctly. A bobbin designed specifically for this machine is not used. Make sure thread passes completely under upper and middle thread guide. Remove any knots or tangles. Decrease the upper thread tension. Adjust the lower thread tension. Replace the bobbin case with a new one. Check that the bobbin is wound so that it about 80% full and that the thread is evenly wound. If the bobbin is not correctly wound, replace the bobbin with one that is correctly wound or rewind the bobbin. Use the correct bobbin. p.36-37 p.86 p.85 p.15 p.15 p.15 202