S-7780A
7. TROUBLESHOOTING
68
Problem
Possible cause
Page
15 Incorrect thread trimming
(Upper and lower threads
are both not being
trimmed)
・
Is the fixed knife or movable knife damaged or worn?
Replace the fixed knife or the movable knife.
・
Is there not enough of a meshing amount between the upper knife
and the lower knife?
Adjust the tip of the upper knife to the lower knife index position
so that the knives mesh.
59*
16 Broken
needle
・
Is the material being pushed or pulled with excessive force during
sewing?
・
Is the needle properly installed?
If it is incorrect, install the needle correctly.
・
Is the needle tip bent? Is the needle tip broken, or is the needle hole
blocked?
Replace the needle.
・
Is the needle and rotary hook timing correct?
Adjust the height of the needle bar.
Adjust the clearance between the needle and the tip of the
rotary hook.
・
Is the needle and feed mechanism timing correct?
Adjust to the standard timing.
・
Try pressing the special locus key and selecting No. 2 or No. 3.
・
It is extremely dangerous to leave any pieces of broken
needle sticking in the material. If the needle breaks, search
for all pieces until the whole of the needle is found again.
・
Furthermore, we recommend that thorough steps be taken
to account for such needles to comply with product liability
regulations.
55*
*
56*
22
17 Material does not cut
properly.
・
Is there no clearance between the upper knife and the needle plate,
or is the upper knife positioned too high?
Adjust the position of the upper knife.
・
Is the cutting blade of the upper knife worn?
Replace the upper knife.
62*
63*
18 Machine does not operate
when power is turned on
and treadle is pressed.
・
Is the power supply connector
disconnected from the control
box?
Insert the connectors
securely.
7
・
9
・
10
19 Machine does not operate
at high speed.
・
Is the sewing speed setting or backtack stitch speed setting too
slow?
Set a higher sewing speed.
17
・
18
20 Machine stops during
sewing.
・
Is the power supply voltage too low?
Check the power supply voltage.
(If the power cord is too long or too many appliances are being
run from a single outlet, this may cause voltage drops which will
in turn cause the reset function to activate and stop the
machine, even if the power supply itself is normal.)
*
NOTE
0469M
1452D