Brother International HE-800B Instruction Manual - English - Page 90

11. TROUBLESHOOTING 11-4. Uneven seams (2) ...... Lower thread is lifted up at the sewing start The end of the lower thread protrudes above the seam at the sewing start Items with a "*" in the "Page" column should only be handled by a qualified technician. Cause Check Remedy Lower thread retainer Lower thread retaining Adjust the lower thread retaining amount. amount Page * 4003Q Lower thread clamp Lower thread clamp Adjust so that the lower thread clamp plate opens opening timing when the feed mechanism moves 6 - 7 mm. 70* Lower thread clamping ・If the lower thread clamp and lower thread presser force are bent, replace them. ・Check that the screws are tightened. Screw * Lower thread clamp 3999Q 11-5. Uneven seams (3) ......Seam lifts up at the sewing start Seam lifts up and does not tighten at the sewing start Items with a "*" in the "Page" column should only be handled by a qualified technician. Cause Check Remedy Upper thread trimmer Upper thread trimmer Adjust the timing so that the upper thread trimmer gradual opening timing gradually start opening when the feed mechanism moves about 1.5 - 2.5 mm. Upper thread trimmer Apply grease to the inclined face of the opening cam. operation Upper thread feeding Thread take-up amount Loosen the screw to decrease thread take-up amount so that upper thread does not pull out of trimmer assembly at the sewing start. Page 69* 69* Screw Decrease Increase * 4000Q 81 HE-800B