Brother NV-10A Service Manual page 192

Repair Manual
Problem Primary factors and causes
11 Threading not Thread pushed out at the hook
possible. end.
• Vertical slippage in needle
Hook extends right of the needle
hole
• Wide gab between right side
• Needle curvature
• Needle slant (hole slant with
• Threader hook assy.
• Vertical slippage in needle
Does not go into needle hole
because of hook tip curvature.
When the threader Threader shaft tangling
lever returns, it
stops part way
Bad thread guide shape
through.
Needle thread shaft and top gap
too small
Needle thread Bad needle stop position
lever operation
• NP sensor damage
catches part way
through.
• Grease or dirt adhering to
• Rotation shutter damage
• Bad needle thread block
12 Either upper thread Upper thread tension is high/low
tension or lower (check the screw lock on the
thread tension tension disk tension adjustment
screw).
Lower thread tension is too
strong / weak
(Check inner rotary hook screw
lock)
Upper thread or lower thread
unsuitable
6 - 6
thread block
of needle and hook guide
slanted attachment of
needle block)
slippage
thread block
NP sensor
rotational position
Repair method
Adjust needle thread block
(4-14)
Replace hook assy.
(2-39) (3-49)
Replace needle
Replace needle bar
(2-38) (3-50)
Replace hook assy.
(2-39) (3-49)
Adjust needle thread block
(4-14)
Replace hook assy.
(2-39) (3-49)
Replace needle bar supporter
assy. (2-39) (3-49)
Replace hook assy.
(2-39) (3-49)
Replace needle bar supporter
assy. (2-39) (3-49)
Replace main PCB assy.
(2-16) (3-26)
Remove grease and dirt
Replace upper shaft assy.
(2-30) (3-9)
Adjust needle thread block
(4-14)
Upper thread tension with
Schappe Spun Sewing Thread
#60 is 0.41 - 0.46 N (42 - 47 g)
(4-7)
Lower thread tension with
Schappe Spun Sewing Thread
#60 is 0.1 – 0.12 N (10 – 12 g)
(4-16)
Replace upper thread or lower
thread
Items for Inspection method
Inspection and standards
Threading Confirm that when
function threading is carried out
with Schappe Spun
Sewing Thread #60 /
#11 needle and
Schappe Spun Sewing
Thread #30 / #16
needle, that the
threading lever moves
smoothly and that
threading through the
needle hole is possible.
Upper thread Check that the thread
tension tension is good during
actual sewing.
Lower thread
tension