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21.
NEEDLE THREADER
(CHECKING THE HOOK POSITION IN VERTICAL DIRECTION)
Case A (Hook point is too high)
Adjust needle threader position setter slightly down
and check that the clearance between the top of hook
and top of needle eye is 0 mm.
Case B (Hook point is too low)
Adjust needle threader position setter slightly up and
check the clearance between the top of hook and top
of needle eye is 0 mm.
Check that the needle threader position setter a and
the needle bar crank rod assembly b is parallel.
In case part a and part b are not parallel or the hook
does not work, readjust needle threader by loosening
the screw.
If a and b are not parallel, the needle threader will
not be held by the needle threader position setter
(refer to Fig. 1), the hook will not enter the eyelet of the
needle (hook will not move) and the needle will not be
threaded when the needle threader lever is lowered. In
this case, loosen the screw securing the needle
threader position setter and turn the needle threader
position setter slightly to the left to make it parallel.
In addition, if the needle threader position setter is
turned too far so that it is still not parallel to left, it may
hit other parts, causing damage (refer to Fig. 2). If a
part is damaged, it must be replaced. If no part is
damaged, loosen the screw securing the needle
threader position setter and turn the needle threader
position setter slightly to the right to make it parallel.
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...