Brother S-710A Service Manual page 146

22. TROUBLESHOOTING
Problem
13. Movable knife does
not operate.
14. Broken needle
0469M
15. The stitch lengths in the
normal feed direction
and reverse feed
direction are not equal.
16. An impact noise is
heard from the quick
reverse solenoid.
17. Oil gauge is not visible
in oil sight glass.
Oil gauge
0979M
139
• Is the resistance between terminals 3 - 4 of the sewing machine
connector normal?
Measure the resistance between terminals 3 - 4 of the sewing machine
connector with an ohmmeter. If the measured value is not normal,
replace the thread trimmer solenoid.
• Is the sewing machine connector
disconnected from the control
circuit board? Or, is the thread
trimmer solenoid
disconnected from the sewing
machine connector?
If the sewing machine connector
is connected correctly, there may
be a problem with the control
circuit board. Contact the place
of purchase.
• 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 bent, is the needle tip broken, or is the needle hole
blocked?
Replace the needle.
• Is the needle and rotary hook timing incorrect?
Adjust the height of the needle bar.
Adjust the clearance between the needle and the rotary hook.
• Is the needle timing advanced too far with respect to the feed dog?
Retard the needle timing.
Caution
• 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 through steps be taken to account
for such needles to comply with product liability regulations.
• Is the eccentric pin adjusted properly?
Adjust the eccentric pin.
• Is the quick reverse solenoid clearance correct?
Adjust the position of the solenoid lever.
• Is the oil tank empty?
Fill the oil tank with oil.
• Is the rotary hook lubrication adjusting screw too loose?
Check the rotary hook lubrication amount, and adjust the rotary hook
lubrication adjusting screw.
• Is the oil gauge damaged?
Replace the oil gauge.
Possible cause
cord
SL-710A
Page
104
0987M
58
-
Instruction manual
-
67
68
67
69
52
59
73
42