Brother International BM-917B Instruction Manual - English - Page 34

14. TROUBLESHOOTING Problem 13. Thread winds onto looper in machine stop position. Possible cause • Is the auxiliary tension too weak? Adjust the auxiliary tension. • Set the needle drop position to the outside of the button thread hole. 2070M 14. Thread remains on material top at first stitch. • Is the thread being used too thick? Use a finer thread. • Reduce the number of stitches. • Is the auxiliary tension too weak? 2071M Adjust the auxiliary tension. • Is the thread take-up amount for the rotor too large? Reduce the scale setting for the rotor. • Is the seam uneven (is the material not being fed) at the start of sewing? Increase the presser arm pressure. 2072M Normal number of stitches 15. Button pops out of the button clamp at the sewing start. 16. Broken needles • Does the button size match the button clamp? Use a button clamp that matches the button size. • 10-20 mm buttons: Standard button clamp • 10-30 mm buttons: Optional button clamp • Do the needle drop positions match the button thread holes? Adjust the vertical feed lever and the transverse feed plate to match the distance between the button thread holes. • Are the positions of the feed plate and button clamp correct? Adjust the installation positions of the feed plate and button clamp assembly. • Does the button size match the button clamp? Use a button clamp that matches the button size. • 10-20 mm buttons: Standard button clamp • 10-30 mm buttons: Optional button clamp • Is the size of the feed plate hole too small for the needle drop position? Use a feed plate with a larger hole. 0469M 17. Incorrect thread trimming Caution • It is extremely dangerous to leave any pieces of broken needle sticking in the material. If the needle breaks, search for all pieces until the whole of the needle is found again. • Furthermore, we recommend that through steps be taken to account for such needles to comply with product liability regulations. • Is the fixed knife or movable knife blunt? Replace the fixed knife or the movable knife. • Is the position of the fixed knife or movable knife correct? Adjust the positions of the fixed knife and movable knife. Page ・ 16 11 ・ ・ ・ － 13 ・ 16 ・ 16 ・・ 16 ・ － ・ ・ 11 ・ 24 ・ － － ・ － ・ 22 2073M BM-917B, 917C 28