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5.
NEEDLE BAR HEIGHT
STANDARD
When the machine is in test mode and pattern is selected, and the balance wheel is turned so that the needle
meets the rotary hook point, the clearance between the upper end of the needle eye and the bottom of the rotary
hook point should be 1.0 to 1.4 mm.
ADJUSTMENT
1.
Put the machine in test mode and select pattern .
2.
Turn the balance wheel so that the needle meets the rotary hook point.
3.
Loosen the screw of the needle bar crank rod assembly.
4.
Move the needle bar vertically to adjust the clearance to between 1.0-1.4 mm.
5.
Tighten the screw of the needle bar crank rod assembly.
NOTE: The needle clamp should be parallel to the side of the needle plate. (Refer to (E)) If the needle clamp is not
parallel when you adjust the needle bar height, it may result in sewing troubles.
Adjustment Points
1.
If the needle bar height is too low or too high, skipped stitches, split thread or cut thread may occur. Refer to
the illustration below.
2.
While adjusting the needle bar height, check the needle threader. (Refer to NEEDLE THREADER 21 and 22
on pages 37 and 38.)
Summary of Contents for BL7800
Page 1: ...4 2001...
Page 4: ...2 1 MECHANICAL CHART...
Page 9: ...7 1 DISASSEMBLING AND REASSEMBLING THE OUTER PARTS AND MAIN PARTS 8 2 LEAD WIRE ARRANGEMENT 19...
Page 15: ...13...
Page 17: ...15...
Page 19: ...17...
Page 21: ...19 2 LEAD WIRE ARRANGEMENT...
Page 43: ...41 Main PC board...
Page 44: ...42 Power supply unit Power 120 Power 230...
Page 45: ...43 Operation board Other PC boards...
Page 46: ...BL7800 T1010141...