Brother International EF4-B561 Service Manual - Page 34

Note on Items 1 and 2: Broadcloth tends to pucker so that the thread tension must be decreased as much as possible. Use a single type presser foot for efficient feeding. Note on Item 3: If wooly nylon thread is used for double chain stitches, it can resist stretching up to 130 to 150%. Jersey tends to deviate much so decrease the presser pressure (to 2 to 3kg) and use a double type presser foot. Remarks: If a single type presser foot is used except when sewing thin materials, initial stitches may skip, the thread may break, and chaining-off thread break may occur. Note on Item 5: Denim also tends to deviate much so that the presser pressure must be decreased to 2 to 3kg (by about 12 to 15 screw threads). Use gauge parts for denim specification. 8. TROUBLE SHOOTING ❑1 THREAD BREAKAGE (Overlock Stitch Needle) CHECK POINT 1 Wrong threading. - 2 Excessive pressure of tension disc. 3 Poor thread quality. - 4 Needle groove or needle eye poorly finished 5 Wrong position of looper thread take-up. - 6 Needle thread passage has flaws. - 7 Needle plate has flaws. ADJUSTMENT Refer to "Threading diagram." Adjust to proper pressure. Use thread of good quality. Change needle for a good one. Adjust to proper position. Change thread guide for a new one. Change it for a new one or smooth surface with oil stone or buff. Flaws PAGE 28 24 8 Under looper has flaws. 9 Wrong timing of needle and looper. Change it for new one or smooth surface 18 with oil stone or buff. T ------ Blunt Flaws Adjust to proper timing, needle clearance 19 and position of needle guard. - 32 -